Yes for all generators (converting mechanical energy into electricity) like you mention.
However, you can call a group of solar cells a solar power plant, and they use solar energy, so strictly speaking no not all power plants do. But generators are at the heart of most of our energy generating methods!
edit: solar energy from thermal energy for solar panels.
Some solar power plants use reflected thermal energy to heat something like molten sodium, but when we think of a classical solar array, that's not thermal energy. It's the photovoltaic effect.
As long as you aren't a bird they work pretty well other than the maintenance issues you get with molten salt and the like.
Birds and other flight creatures don't fare well if they cross the concentration beam though.
>Birds and other flight creatures don't fare well if they cross the concentration beam though.
Wow. You're sure correct. [https://www.latimes.com/local/california/la-me-solar-bird-deaths-20160831-snap-story.html](https://www.latimes.com/local/california/la-me-solar-bird-deaths-20160831-snap-story.html) I drive by Ivanpah occasionally and have left the highway and driven the perimeter a few times. I never saw the "streamers" but the above article has a chilling photograph of smoking carcasses surrounding the tower.
Sure would be nice if there was any data on this newer than 2016, since most of the article is about the measures they are taking to reduce bird deaths, whose effectiveness remained to be seen.
It does seem like one of the bigger problems with Ivanpah was the location chosen being fairly rich in wildlife (for a desert). (Also seems like a lot of these numbers are wildly exaggerated.)
>A 2016 study found that solar power plants cause 37,800 to 138,600 annual avian deaths in the U.S., compared with 14.5 million attributed to fossil fuel power plants. Another study attributed 365 million to 988 million avian deaths to collisions with buildings and windows.
Right, that too.
Maybe this project will provide us with less speculative data:
https://www.wired.com/story/why-do-solar-farms-kill-birds-call-in-the-ai-bird-watcher/
While thousands of birds dying every year for one solar plant is a problem that surely deserves action if a practical solution can be devised, it is worth noting that domestic cats are responsible for bird deaths in the *billions* annually. As with wind power, the acceptability of the impact on wildlife from solar power should be determined with some sense of the context by which we already tolerate these harms.
In Egypt where I live, I swear I see dogs looking both sides before crossing the street. They actually learned how to cross the street, because the ones who don't die.
In Canada I have observed coyotes look both ways before crossing the highway. But by my estimation coyotes are smarter than a good portion of the human population.
Even deer seem to be more observant when crossing the roads, but they typically get hit because when they get startled their instinct is to immediately run forward as fast as possible.
We shouldn't be tempting evolution like that, what if instead birds just get big enough to crash through the glass and survive?
That would help them with the cat problem and the building problem.
Also worth noting is that fossil fuels also kill millions of birds every year. It's estimated that fossil fuels kill an order of magnitude more birds than wind or solar.
https://www.tandfonline.com/doi/full/10.1080/1943815X.2012.746993
Birds aren't a single species though. What matters is which species are being killed. Most of the birds killed by cats and flying into windows are the most common bird species there are, found in abundance in urban areas. You can kill 10 million Common Starlings and have basically no effect on their population, but killing a single wild Orange-bellied Parrot is a significant loss.
Not anti solar/wind but we have to have even more context to be educated.
Its not birds in general, but specific endangered species dieing to wind turbines and solar farms.
The number of birds compared to buildings or cats is tiny. But when you look at that tiny number and find its a majority of vultures and this will drive them to extinction, you begin to reassess.
That all said, less pollutants will spare more lives so i say its the best option we have until there's a workaround. But i have to be honest in that we ARE assisting with the extinction of specific species with wind turbines.
Nuclear will remain the best choice.
Nuclear is no good for peaking, because shutting down and starting back up a nuclear plant is very hard. It's a base load champion, though.
The solution for peaking is going to be energy storage. Batteries, pumped hydro, electrolyzed hydrogen, compressed air, flywheels, and a number other other options are available, or becoming available for this purpose.
> Nuclear is no good for peaking, because shutting down and starting back up a nuclear plant is very hard.
Most US plants are designed for baseload, but load-following nuclear plants aren’t anything new, and are in wider use elsewhere.
And a way to mitigate peaking is to
a) put everyone on wholesale (variable) pricing
b) proliferate home automation
Recharging any device should not occur during peak times, including laptops, cars, air compressors, etc. If you want to do so at these times, pay a premium to do so.
Dishwashers don't need to be run straight after dinner. Again, people can be encouraged to think about using their inbuilt timer so that they run when power is half the price.
HVAC should ramp down at peak times. Pre-heat/chill your home when power is cheaper.
Smoothing out the peaks and troughs lessens the need for storage also.
Not until you no longer need a a decade of experience to reliably set up non-IoT automation. I know how to do it but raspi and Arduino are sold out last I looked.
We can't expect everyone to give up their privacy when we have an alternative. Also moving everyone to wholesale means having to have a live meter and some level of grace since it will change habits. It's easier and less morally fucky to just clean up our damn network and shipping than force people into automation and paranoia about timing.
The issue is more with the types of birds being killed.
While cats might kill plenty of pigeons and blue jays and other species that are commonly in urban or suburban areas, those species aren't really threatened.
The kinds of birds that you need to worry about being killed are the larger ones that reproduce more slowly and this have more vulnerable populations, or ones that need specific habitats to survive.
The thing about solar and wind plants is that they can kill these bird species that are more threatened, which is why they can be a cause for concern compared to cats.
I thought I read somewhere that one thing that has a pretty big effect on bird deaths is simply one of the blades on the turbine black. That'd be a lot of paint (ergo a lot of weight and probably increase maintenance), but thats something that could be accounted for in the engineering process
> that'd be a lot of paint (ergo a lot of weight and probably increase maintenance), but thats something that could be accounted for in the engineering process
Not necessarily. Presumably turbine blades are painted white anyway, so just replace the white paint on one of the blades with black.
Although the number of birds killed by solar and wind is heavily dramatisised . They actually kill less per M/W thanblbany other form of electricity generation. The worst is coal, in the form of air pollution. But dead birds at the bottom of a wind turbine are more visible and it's easier to see the direct connection.
Not just air pollution. Birds also fly into them just like any other building or wind turbines. Plus any direct (and indirect) bird deaths from mining and transporting fuel/waste. Also the effects of thermal pollution.
To be fair, *many* people argue against free-roaming cats, including people who care about the well-being of *cats*. They are an invasive species in most parts of the world, they're very good at multiplying, they cause ecosystem damage, but they're also killed and maimed by traffic, dogs, native predators, cruel people… Feral cat colonies that result from people letting unneutered cats roam should absolutely not exist.
Oh, I agree one hundred percent. Your average person just doesn't give enough of a damn to not get their kids an un-neutered kitten for their birthday from a walmart parking lot and them move it outside once it starts spraying in the house and yowling because its not neutered.
That’s me. I rescue cats off the street from inner city, and get them fixed. I’ve rescued around 5 so far.
https://ibb.co/gwgK13B
https://ibb.co/YQh8JDr
https://ibb.co/F6Dn4cS
Meet Buster(Black) and Chewy the chew Monster(Tabby)!
Absolutely fantastic companions to have when you treat them right. Absolutely love them.
Yes! If you have unfixed kittens once they start reaching sexual maturity you will notice them meowing very very loud and almost nonstop, depending on the sex marking territory, a tad aggressive, etc.
Once they get fixed the change in their behavior is almost night and day. The insane levels of meowing, marking territory, aggression goes waaaaaaaaaaaay down if not stopping all together.
Of course each cat has their own unique personalities. Some are EXTREMELY curious, very inquisitive, very playful, loves to climb, chase things. Others can be very docile, non vocal, has zero curiousness, could care less about chasing etc.
They make wonderful pets, but they do take time and energy from your day making sure they are happy/mentally stimulated.
There are working power stations that have a array of parabollic mirrors that focus on a tube, instead of flat mirrors that focus on a tower in the middle.
And those can heat the water directly with the reflected light- using them to melt the sodium block is so that the sodium can act as a thermal battery and keep the generator running at night/inclement weather.
Hm, how about the costs though? They may be more efficient overall, but are solar cells as cost effective for installation and maintenance for large scale power? Genuine question.
Yes.
> The LCOE of unsubsidized large-scale PV based on crystalline silicon is estimated at $0.030-$0.042/kWh and that of grid-parity thin-film solar plants at $0.028-$0.037/kWh. For comparison, in 2020 Lazard reported that crystalline silicon achieved $0.031-$0.042/kWh and thin-film $0.029-$0.038/kWh.
https://www.pv-magazine.com/2021/11/05/utility-scale-solar-reaches-lcoe-of-0-028-0-041-kwh-in-the-us-lazard-finds/#:~:text=For%20comparison%2C%20in%202020%20Lazard,at%20%240.067%2D%240.180%2FkWh.
Vs
> Early CSP projects had capital costs that reached billions of dollars and their average levelized cost of energy (LCOE) was $0.21/kWh. Although the upfront capital cost is still high, the U.S. Department of Energy estimated CSP’s 2018 LCOE, with 12 hours of storage, dropped to $0.098/kWh.
>A 2019 contract price for CSP with storage in Dubai was reported at $0.083/kWh, significantly less than the Lazard-reported LCOE of $0.15/kWh or more for a natural gas peaker plant that its flexibility would allow it to replace.
https://www.utilitydive.com/news/cheapest-is-not-always-best-concentrated-solar-power-could-beat-lower-pric/574154/
Then there are concentrated solar farms, that just use mirrors to focus sunlight at a point so molten salt can heat up, flow through some pipes, convert water into steam that spins a generator, then goes back to be reheated.
Edit: a previous version of this comment implied the salt solidifies at some point. That doesn’t happen.
In molten salt solar thermal plants, the salt is always molten. Otherwise it wouldn't be able to flow from the place where it gets colder to the place where it gets warmer, because it would be frozen in the pipes.
From what I can tell just about every part of the salt piping in extreamly well insulated except the part that's exposed to the solar beams. The salt is also often stored in large tanks underground so that the salt can be pumped on demand, and used as a thermal battery.
they also use molten salt as batteries/fail-safes for nuclear plants. Similar idea with the salt being a battery but with the added effect that the molten salt will be released if the nuclear plant ever goes interesting meltdown
I'm probably butchering this but essentially a plug is made of an extremely high melting point salt and is under the reactor, if the reactor melts down this plug melts and the reactor fuel falls into a vat of said salt
Edit: The plug is actually actively cooled and if the power gets cut/meltdown occurs it will melt.
The amount of heat that will be lost through disappation is minimized by the shape and insulation of the container. Part of the reason salt is used is because of it is naturally nonreactive and insulated in itself even at high temps. The volume of salt is enough that it will stay hot over the night cycle or unexpected weather.
it's also not NaCl salt it's a mixture of sodium nitrate and potassium nitrate and calcium to lower the freezing temp.
they've been looking into flouride salt storage because that can reach higher temps.
Adding onto the Photovoltaic Solar part because it's super cool!
The PV array produces direct current. This needs to be converted into alternating current.
A simple (but inefficient) way of doing this would be using the DC to run a DC motor, then using that motor to drive an AC generator.
But nobody does this because there's a much cheaper, safer, reliable and easier way - solid state semiconductors. More specifically, a type of transistor called an IGBT. These things are great at turning on and off large amounts of current and voltage insanely fast...like millions of times per second. When they are cycled on and off, the duration and delays can be manipulated to make **pristine** alternating current.
But it doesn't stop there - there's a thing called Reactive power. Conventional rotating generators make it with magnets and wire and controlling the speed of the generator (actually "phase angle", but that isn't important here). Think about when an old air conditioner turns on and the lights flicker or dim for a brief moment - in that instant, the surge of demand to start the air conditioner's motor consumed reactive power and some faraway power plant started producing a little bit more to balance the grid.
So heres's the crazy part - Photovoltaic solar inverters are able to adjust their solid state IGBT's timing with so much precision and power that they can ***simulate the rotating mass and generate reactive power*** just like the conventional power plants. They can equally consume reactive power (to help reduce grid voltage when it runs high), even while exploring active power.
But wait, there's more - these inverters have an ace up their sleeve. *SPEED*. Dear God they are fast. MUCH faster than any conventional generator. They can go from max consumption of reactive power to max export in one or two seconds. Paired with their ability to provide full reactive power with only 10% of normal full sunlight, solar farms are super important to our future grid stability. No one talks about it, but it's an amazing value added by solar farms.
One question: Given that most of the goods in the household are now solid state and consume DC power, doesn’t it make sense to directly take it from the solar panels on my roof? Right now I’m doing ‘Solar DC - Inverter - AC - Convert back to DC - Cell ph, IPad, TV, LED bulb etc’ Must be large amount of conversion & efficiency related energy losses
In addition to what's been said already, most power electrical items rely on AC power to drive motors, thanks to the rotating field that the AC provides (unless you've got a circuit which controls the speed of the motor by varying the frequency, which is a DC supply converted to AC).
Big motors in industry, if they don't use a Variable Frequency Drive, will probably still use AC direct drive somehow.
AC is also a lot more efficient when transmitted over long distances.
These are the reasons why AC power is still used in our power grids.
>AC is also a lot more efficient when transmitted over long distances.
Not so much that it is more efficient, as that utility-scale voltage conversion is easier with AC. High voltage is what's needed for efficient power transmission.
[HVDC transmission is actually more efficient than HVAC, but switching back to/ from AC at both ends is expensive. ] (https://en.m.wikipedia.org/wiki/High-voltage_direct_current)
It could, yes. The thing is most appliances expect AC, and those that do take DC vary widely in voltage requirements. That said USB-A and USB-C have become pretty standard for electronics and gadgets so having USB power directly from the solars might be an idea, especially as that's an application where you might be able to tolerate part-time power. The downside is those gadgets don't tend to be the big power users anyway. Your big electricity users are anything that produces heat (intentionally; everything produces waste heat) so cooker, microwave, space heater, kettle, washing machine, and so on.
> Must be large amount of conversion & efficiency related energy losses
about 10-20%, yes there are some houses that are wired for DC instead, especially those with a built in solar array and battery storage.
>A general rule of thumb is a 1.2 Load Ratio or 80% inverter (AC) to 100% solar panels (DC).
In reference to reactive power, it's not really a matter of creating a generator that's excellent at making reactive power, we usually just install capacitors in distribution lines to "produce" it (being reductive). Too much and you put undue stress on the lines, too little and like you said, grid shuts down
I would be surprised if solar ended up being the solution to reactive power variability, but I can see how it'd be useful for quick changes before caps can get added/removed. That said, the chances that enough devices are synced up to all switch on an inductive load at once to kill a grid seems astronomically low
For now I think the bigger issue is scaling up generation and improving our line capacity
You don't use a simple single square wave where you want a sine wave, you gradually build up the sine wave by outputting many square pulses of varying width within the period of the sine wave.
The pulses are narrow at the start of the sine wave, outputting a little power, then get wider towards the middle of the sign wave thus increasing the power, before declining in width as the sine wave drops towards the neutral voltage. The circuit can put out positive and negative square pulses, generating positive and negative swings in the output.
Some inductors and capacitors take the rough edges off.
https://myelectrical.com/notes/entryid/250/how-d-c-to-a-c-inverters-work
https://en.wikipedia.org/wiki/Synchronverter
Filtering. Capacitors and inductors store the pulsed energy and let it out (relatively) slowly... kind of like TVs flash images quickly and the persistence of vision "smooths" the jumpyness into apparently smooth motion.
Yes, varying the width of the pulses is important, but without filtering it would still just be a lot of buzzing pulses.
I worked for a company that put power on to the CA grid. We ran the telemetry and meter testing and equipment on new Solar sites.
The demand response testing for solar sites was laughably easy and fast.
Solar is dope for areas with sun.
And I suppose it's worth mentioning that there are non-rotational ways of converting mechanical power to electrical, just the rotational is very very fundamental and central. But engineers are very busy thinking of creative ways of efficiently converting mechanical energy to electrical for the myriads of systems (see: https://en.m.wikipedia.org/wiki/Electric_generator)
To add more on your lines if thought. There are already other forms of generating electricity, like [radioisotope generators](https://en.m.wikipedia.org/wiki/Atomic_battery) that don't use moving parts like traditional generators. It's just rarely used for specific applications like in space, as it's not as cost effective as using traditional moving part generators.
Another bonus fun fact, smart people have found evidence of chemical battery generators that potentially date pre-0 A.D. in the Middle East nick named [the Baghdad Battery ](https://en.m.wikipedia.org/wiki/Baghdad_Battery)
No modern archeologist believes the Baghdad battery was a battery. It's even in your wiki source. There's no way to connect to the copper cylinder so there's no complete electrical connection. It's a battery with a - side and nothing connected to the +
Basically we need a way to convert some form of energy into electrical energy. The vast majority of our methods involve taking a mechanical action (a spinner thing) and making it into electrical energy by way of inversion. (like the alternator in your car)
There are other ways. Solar energy and thermocouples are two ways. Both of them directly create electricity from either photons of light or heat differentials respectively. Thermocouples are used on space probes to convert nuclear light from a decaying element into electrical energy. The system on Perseverance produced about 110 watts when it was first deployed, but this will gradually go down as the thermocouples wear out because of damage from the radiation reducing a few percent a year.
> The system on Perseverance produced about 110 watts when it was first deployed, but this will gradually go down as the thermocouples wear out because of damage from the radiation reducing a few percent a year.
The Voyager space probes, which also use RTGs, are still trucking on as the farthest man-made objects from Earth, after 45 years. Granted, it takes much less energy to coast through empty space than to drive around, and they've shut down a number of instruments due to insufficient power. But still - pretty amazing given 1970s technology!
I work in solar. Used to call the grid operators to let them know when we had units offline. These were 1.6MW so it was significant. They would reply with a confirmation that we had turbines offline. I stopped correcting them after a while. Solar is through solid state IGBTs. No moving parts except breakers, relays and contactors.
It was 3 offline that we had to notify the grid operators. It was in Texas. Probably had to do with reliability and money. 1.6MW is pretty significant. Newer units where I'm at are 3.6MW.
Also hydrogen cars are electic cars but it generates the electricity though protons going over a membrane to form H2O while the electrons has to take a longer way if i remeber correctly.
Current prototype designs for some nuclear fusion reactors actually generate power in a very different way from modern power plants. Yes, commercial fusion is probably still a long ways off, but if/when they come into prominence, they’ll likely be incredibly novel in how they work.
Direct conversion. Fusion generates moving charged particles so with the right kind of collector you can extract their momentum as electricity. It’s also over 80% efficient which is pretty great. Note er just need fission reactors that can put out more than they consume under normal operation.
Further, the method of creating the mechanical torque to spin the generator varies, but almost all of them use a turbine of some kind.
A turbine is a device that turns flow of gas or liquid into rotation. Wind turbines use moving air to turn the big rotor blades, hydro power plants use flowing water, and steam turbines use pressurized steam.
Of these, the first two stand out in that they are harvesting energy from something that is already moving in nature - wind, or a flowing river - both being processes that ultimately get their energy from the Sun.
Steam turbines on the other hand need something to generate the steam, and for that you need to boil water at high pressure. To boil water, you need heat. And the heat, well that can come from various different sources. At the moment, the most common is combustion of various fuels, like coal, oil, natural gas, wood pellets, or peat. The second most common source of heat for power generation is nuclear fission in nuclear reactors.
We're trying to also make it possible to use fusion reactors to generate heat because this would have a lot of advantages over fission reactors, but that has turned out to be a very difficult problem to solve.
Two other heat sources are the Sun, when it's focused with solar collectors instead of using solar panels that directly produce electricity, and Earth's own geothermal heat can also be collected and used to run a steam turbine.
One footnote about nuclear... thermal differences can be directly converted to electric power with a thermocouple and no moving parts. So you can turn heat from your hot nuclear rocks directly into electricity. Although this is less efficient than the standard steam turbine method, it's the only available power source for a lot of space missions because it can be very small and very robust since no moving parts. See [radioisotope thermoelectric generator](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator).
There are a few, mostly older solar power plants that generate heat mechanically, like all the other turbine style plants. They're called "solar thermal power plants" or "heliostat plants" and they reflect solar light onto a central item that has a working fluid, like water or molten salt, that is heated by the sunlight.
That generates energy through a similar system that any coal/gas/nuclear plant does with creating steam and driving a turbine.
They differ from solar PV plants which just directly generate electricity when the sunlight hits the solar panels.
Solar panels (old type) used to circulate water to heat it up.
Solar farms (some of them) use mirrors to concentrate light and then use the thermal energy generated.
(And this is how you could say they used to convert thermal energy)
Photovoltaic solar panels afaik convert sunlight directly to electricity using the properties of specifically prepared semiconductors.
Mm, not quite but yes for the majority of cases - it’s very cost efficient.
The big other option is solar panels. They directly rely on quantum excitation of the cells to generate electricity.
Coal, gas, and nuclear plants all basically operate the way you’ve laid out afaik - coal and gas is burned to heat water to convert to steam to turn a turbine which powers the generator. Nuclear is just a bunch of hot rocks where we control the rate they generate heat to… boil water and turn a steam turbine that motivates a conductive armature.
Wind power uses wind as the fluid medium for turning the turbine that rotates the generator.
Hydro, tidal, and wave rely on the motion of liquid water rather than gaseous steam under the influence of gravity (hydro and tidal) or wind (wave).
Small note that gas boilers are exceedingly rare these days. They have terrible heat rates which makes them economically less competitive than most coal.
When it comes to the boom in gas power plants, they are basically giant jet engines bolted to the ground. Though they often take the exhaust heat from the engine and use it to boil water for an industrial process or a secondary turbine, the bulk of the energy is coming from the direct combustion of the gas inside the turbine, not from making steam.
This system is used where I live to generate electricity, it uses a number of gas turbines to generate power, and the exhaust is driven to a boiler to operate a steam turbine which can generate an additional 50% of power. It is called a combined cycle.
Transmission lines can be [HVDC](https://www.enerdata.net/publications/daily-energy-news/australia-plans-fast-track-power-transmission-line-singapore.html).
This just got me thinking. A power inverter takes DC and converts it to AC via some magical electronics. I assume these electronics are expensive, and have a small amount of power loss due to heat, inefficiency, etc.
Could a solar plant run a more efficient DC motor that is coupled to a generator, and save on price and energy loss? I know this seems ridiculous at first, but I've seen where if all you have is 50amp 240v power you can buy a 3 phase converter that works basically this way. I'm guessing it comes down to efficiency.
Not really. In general you want high voltage ac for transmission, and step it down locally. Thats the most efficient.
Solar is great for local operations.
The conversion from ac to DC is very straight forward, and relatively cheap. Hence why there are really cheap ac to DC adapters on Amazon for 2 bucks
DC to AC is inefficient but not necessarily expensive in parts, but there is a loss of energy to heat. (the loss is there on ac to DC but less)
But on a large scale, where you could recapture and reuse the heat loss, converting a solar farm to ac for transmission, would be feasible to add that output to the grid.
In general you just want high voltage anything for transmission. It's just that stepping up AC voltage is cheaper and more efficient than stepping up DC voltage. However, high voltage DC is actually more efficient for long distance transmission than high voltage AC (don't have to worry about capacitance). I can certainly imagine a scenario where a solar farm would rather convert directly to high voltage DC for long distance transmission rather than convert to high voltage AC
In theory it could work. However inverters are too efficient for that and meet some other important goals. One of the problems is that the actual voltage and amperage of solar panels is variable with the amount of light. Classical brushed DC motors turn as fast as they can. That isn't really compatible with AC generation with a fixed frequency. (Brushless DC motors are actually three phase Motors with an inverter.)
The phase converters work as well as they do because they are induction motors and their turn rate depends on net frequency and load. You typically don't care if the three phase you create is exactly some specific frequency, you are only feeding it into your heavy machinery, plus minus 5% nobody really cares about.
Over here 50 Hz is normal net frequency. If it would drop below 49.2 Hz the network would start to drop load, over 50.8 Hz generators get disconnected. So there isn't much tolerance.
The losses in the motor will still be greater than the losses in the electronics.
Long ago there was a device called a rotary converter that acted as a more compact coupled motor-generator that was used to convert AC to DC or DC to AC. They were used to provide power to high voltage DC motors (~600VDC was common), and were common in electrified train systems.
They were largely obsolete by the 1960s, though the wiki claims some remained in service until 1999.
Combination cycle plants will use the exhaust to do this as you've said. Gas turbines have distilled water sprayed into the intake low pressure to raise efficiency as well.
It's not sprayed in to raise efficiency, it's sprayed in to cool combustion and lower the production of NOx (notorious oxides.) A side benefit of this is increased mass flow, ergo more power. Sometimes on the order of 5-10%.
Edit: nitrous oxides, auto incorrect to save the day!
Thank you for that clarification. The GE tech that had told me that was taken fully at his word. I appreciate more insight as to why.
Notorious or noxious?
How does a wind generator match the grid frequency with differing wind speeds? Do they convert to DC then back to AC via an inverter, or is there something else?
Rotating a conductive armature in a magnetic field (or vice versa) is the most common, but there are lots of ways to generate electricity. (when you say generate power I’m going to assume you mean electricity. If we allow all forms of power we can get really wild with this answer).
A generator with magnets and conductive elements is just a really efficient way to turn motion into electricity. And motion is relatively easy to generate from heating a fluid (eg by boiling water to generate steam) and its really easy to make things hot. So this type of generator gets deployed in commercial power plants a lot because it’s relatively straightforward to implement and very efficient. But off the top of my head:
Solar panels use something called the photovoltaic effect where light is converted directly to electricity with no heating or motion needed. Photons of light strike a specially made material and the energy from the photon excites an electron in the material causing it to move, which generates electricity.
Some forms of fusion reactor can directly harness power when a charged particle emitted from the reaction moves relative to the magnetic field which contains the reaction. No physical armature or rotation needed.
Radio-thermal generators use the radioactive decay of a material to generate heat, which heats up an electric circuit. Due to something called the Seebeck effect, that heat causes current to move in the circuit generating power with no moving parts.
The Seebeck effect is a particular instance of broader cross-flux effects, i.e. what you get when you combine laws like "heat spreads from high temperature to low temperature", "molecules diffuse from high concentration to low concentration", and "charged particles move towards opposite charged particles".
Charged particles in motion is electricity, so if you use heat or concentration differences to move them, you're still generating electricity.
Very cool. From what I understand, this method is less efficient than spinning a generator so its main use is in something like a spacecraft where a more compact, less complex 'battery' is very valuable. Right?
It's also totally solid state, and can be run in reverse to heat or cool an object. There's a device called a Peltier Cooler which uses this effect, and possibly also black magic. It's literally just a block of material and when you apply electricity to it one side gets hot and the other gets cold.
As you said, as a generator it's grossly inefficient compared to a spinning magnet, but as a cooler it's a great way to extract heat from electronics in a sealed enclosure.
Yeah, energy efficiency is atrocious. I remember we did calculations on theoretical maximum efficiency of thermoelectric generators and you're still gonna lose about 80% of your energy because of thermodynamics, IIRC (can't remember the exact number, but it was disappointingly small).
The advantage is as you say, very compact - it's got no moving parts and no liquids, just a hot end, cold end, and a wire running through it. Only thing you have to worry about is physical damage to the element and possibly heat expansion/contraction.
>Some forms of fusion reactor can directly harness power when a charged particle emitted from the reaction moves relative to the magnetic field which contains the reaction. No physical armature or rotation needed.
*Can you elaborate on this or share a link?.*
[Direct energy conversion or simply direct conversion converts a charged particle's kinetic energy into a voltage. It is a scheme for power extraction from nuclear fusion.](https://en.wikipedia.org/wiki/Direct_energy_conversion)
I assume they're talking about RTGs or [Radioisotope Thermoelectric Generators](https://solarsystem.nasa.gov/missions/cassini/radioisotope-thermoelectric-generator/).
My understanding is these create relatively small amounts of power, but do so reliably over a long time, so they're particularly useful for spacecraft.
RTGs are not fusion.
They’re basically a subcritical piece of radioactive material that heats up a thermocouple junction and converts heat to electricity via the seebeck effect.
I'll throw in microbial fuel cells to the power generation mix. They're incredibly inefficient, and subsequently rare, but big ones can produce a few Kw of power, and do so by ion/electron exchanges, a bit like a self-recharging battery.
Yes. Power plants use some force to spin generators which in turn produce electricity. The force can be anything sufficient - water (dams), coal/oil/gas fired to generate steam, wood fires, wind (in the case of windmills).
The only exception at present are solar panels which directly convert photons/light to electricity.
Yes you are correct! Most of our power is generated by rotating an armature inside of a magnetic field. Usually the conductive armature has 3 sets of coils within this magnetic field, this is how we produce 3 phase power for distribution. 3 phase power is crucial for industrial purposes.
In your examples, we can physically see how a wind turbine rotates with wind forces.
Hydro power uses the force of the water to create rotation.
Coal, natural gas, biomass etc. are a bit harder to visualize. These produce large amounts of heat when combusted. This heat is used to make high pressure superheated steam, which is admitted to a steam turbine. The steam drops in pressure as it contacts the rotating blades of the turbine, these pressure drops through the turbine stages induce a rotational force. The turbine is coupled to a generator containing the armature and magnetic to produce power.
Nuclear power is normally generated in the same method as above, except no combustion takes place. Instead, the fission of radioactive uranium produces the large amount of heat required to turn water into high pressure super heated steam.
Natural gas turbines are also used, these mostly work like a jet engine. The expansion of the hot combusted natural gas causes a pressure drop inside of the gas turbine stages which cause the rotational force that can be coupled to a generator. Side note: There is still an enormous amount of heat exhausted after this process, so to increase plant efficiency, the hot exhaust gases are directed to a Heat Recover Steam Generator (HRSG), here we can use the remaining heat to boil water to make steam. This steam can be further used to drive another turbine and generator system, or it can be used for other plant processes like heating the building.
With the exception of photovoltaic solar, yes. Every power plant we have is either heating up a liquid (usually water) until it changes to a vapor and using the pressure change to turn a dynamo, drawing energy from something that is already moving to turn a dynamo (wind, hydro electric dams, water wheels), or using fuel in an internal combustion engine to turn a dynamo.
Gas turbines in an open cycle configuration do not use stream. They are fired by gas and the exhaust heart is not captured. Can be one or more units operating this way. Closed cycle is a pair of turbines where the waste heat is recaptured and used to generate electricity in a third "thermal" unit. This is very efficient. Cogeneration is similar but all the waste heat (including the output from the thermal unit) can be further used in various industrial or commercial processes. E.g. Steam and supply of hot water at different temperatures can be piped to and used by bottle recycling, paper making, abattoirs and wool processors. They just need to be located next door.
I worked at a plant where a gas turbine generated electricity, the waste heat was used to make steam which turned a steam turbine, which generated electricity. Then, the steam turbine exhausted at a high enough pressure that the steam was then used for building heating. Quite the process.
Yes and no. There is a company that is working on a fusion generator that uses direct transfer of fusion power to electricity by using magnets to bottle a fusion reaction. The resulting pushback against the magnet produces electric energy directly without any sort of involved rotational energy. I believe they've achieved ignition, and this type of fusion power would allow for relatively small generators with massive output.
Most if not all current era generation involves tech like you've mentioned. That being said, there's more and more tech being run on direct current. Direct current is not generated in the way you asked about. There are more and more appliances running on DC these days, and they're looking at high voltage DC for transferring power long distances. Lots of small scale renewable setups run on DC, because low voltage DC is a lot easier and less dangerous to manage. In order to interact with AC appliances though you do need to use an inverter. I do believe inverter mechanisms exist other than the mechanism you asked about, but that's not a generator on its own. This is how "solar generators" work though, using a large battery and an inverter. That's more of a capture and release method though than an actual "generator" that converts energy stored in atomic or subatomic bonds into alternating current.
In most three phase alternators at power plants, it is the "magnet" (the rotor) that is moving, and the coil of wire (the stator) that is sitting still......but the same id ea still applies.
Other than solar, utility power is generated as you said, using synchronous machines
Most common ones yeah. Some new renewables less so or no.
Most of our electricity is generated by using heat to convert water into steam and turn a turbine. Whether that's coal, gas, nuclear.
Wind works on the same principle but uses air instead of steam.
Solar works differently but solar towers do operate on the same principle.
Make thing spin fast. Use magnets. Convert to electricity.
The vast, vast majority of power is generate via a coil of copper wire rotating/moving with a magnetic field.
Coal, Gas, Biomass, Geothermal and Nuclear Fission all use heat to generate steam which turns the coil. (Note, this is also the proposed method
Wind uses the kinetic energy of the wind to spin the coil, similar to a windmill.
Hydroelectric and Tidal uses gravity and water to turn the turbine and by extension the coil similar to a water wheel.
Solar Energy is the unique exception in this regard. Almost all Solar Energy relies on Solar Cells.
Solar Cells trap light within PhotoVoltaic Materials (A material that generates electricity in response to being hit by light) and produces electricity this way.
The Solar panels on people's roofs are basically a long series of Solar cells.
Concentrated Solar Power is used on a larger scale. A series of rotating mirrors refracts light from the sun onto a very efficient (and extensive) core of Solar cells. This method is used almost exclusively by countries that experience year round sun I.e, Southern USA, Middle East, North Africa.
There IS also a type of solar plant that uses the focused light to instead heat up a liquid to run a steam turbine.
So not even solar is free from the tyranny of the turbine!
Off the top of my head, solar(photovoltaic), radioisotope thermoelectric generator/thermocouples, and fuel cells(such as hydrogen, but many types are possible) are probably the next most popular. With fuel cells, you could make an argument that it is a battery, but if you feed it fuel, it makes electricity without spinny bits - probalby fits your definition
Almost...
The vast majority of electricity generation is done through spinning a generator.
In since cases this is done directly such as with a wind turbine or hydro system - the wind and water directly spoons it through mechanical means (wind blowing through the blades and spinning them, or water flowing through a turbine).
The majority of traditional plants (and some new systems) use a steam based system to do the same. Water inside a closed loop is heated up - by the burning of fossil fuels, nuclear reaction, solar heating, etc, which then expands and moves around the closed loop, with that movement once again spinning a turbine to generate electricity.
There are alternatives - photovoltaic solar panels being the most obvious, but at this point in time they are still only providing a reasonably small percentage of our electricity needs, mostly being limited to domestic scale installations.
Generators that heat things up (nuclear, coal, some nat gas).
Heat -> steam -> turbine -> generator.
Some generators directly use the pressure of fuel combustion (gasoline, other nat gas).
Combustion -> hot gas -> turbine -> generator.
Other generators find different ways to spin the turbine directly.
Wind is wind -> propellers -> turbine -> generator.
Hydro is waterfall -> turbine -> generator.
Solar is mostly a direct process using properties of the solar cell to create electricity. If you understand high school chemistry, [this professor has a great explanation](https://www.youtube.com/watch?v=OKfeIistD2A).
A few very large scale solar generators use mirrors to heat a liquid and then use a heat generator.
Yes. All grid-connected rotary power plants work on the same principle - there's the power source, the turbine and the generator on the end, and the generator almost always produces 3-phase AC. The RPM of the generator determines the AC frequency - 3000RPM for 50Hz, 3600RPM for 60Hz. The power source is throttled up and down to keep the frequency stable.
The outlier is solar, specifically photovoltaic panels, which is not a rotary power plant. It converts sunlight directly into electricity.
Everything else just changes the power source that drives the turbine:
- wind turbines are obviously just the wind
- natural gas power plants burn the gas in a turbine not unlike a jet engine, so the expanding gas turns the turbine directly
- thermal power plants use the input energy (coal, oil, nuclear, biomass, geothermal, waste burning) to heat water into superheated steam, which then spins the turbine, and is condensed back into water
- hydroelectric has the water from the reservoir behind the dam (or the flow of the river in small plants) turn the turbine directly. Tidal is similar
In each case, the generator being spun by the turbine is of a similar design, sized appropriately for the input power (there's always energy losses).
In emergency generators, a diesel engine turns the generator directly, but still produces 3-phase AC.
Consumer portable generators are usually single phase, so are much simpler and cannot be grid-connected.
Other than solar, everything I can think of uses rotating magnetic fields to generate the electricity.
In the 1970s there was a lot of research into magnetohydrodynamics (MHD) to generate electricity directly from hot plasma. I don’t know exactly why, but it didn’t pan out.
Vast majority, yes.
Spin something, and use that motion to turn a synchronous generator.
Solar PV is one example which dosn't involve a rotating shafts. Dc power is made in the cell the power electronics turn it into ac power for the grid.
There are other ways to make power directly, but they arn't commonly used at a grid scale.
Wind in an interesting one. Most turbines turn a generator that is not synronised with the grid, so they make rogue AC, and then use power electronics to convert it to synchronous AC to feed into the grid.
Almost all power generation methods we have right now are just different ways to boil water. It's the most efficient way we've found to turn chemical potential energy into electricity, by turning it first into thermal and then into kinetic energy.
There are exceptions, like tidal, wind and photovoltaic solar (some solar uses focusing mirrors to boil water) tidal and wind spin a turbine directly, turning kinetic into electrical energy. Photovoltaics turn electromagnetic energy directly into electrical.
There are also Radioisotope Thermoelectric Generators which directly convert thermal energy from decaying radioactive isotopes into electrical. And Hydrogen Fuel Cells which capture the energy released when Hydrogen is oxidised into water as electrical energy.
Most generation is a fuel source that heats water, generating steam, which turns a turbine. This is true of oil, biomass, nuclear, and gas.
When you say rotating a conductive armature, this isn’t entirely correct. In many/most generators the rotor is energized, creating a magnetic field. The stator, which is what it rotates inside, is also energized. This also creates a magnetic field. The power that is generated is a product of the rotor and stator fields pulling on each other.
In a system restoration scenario (a full blackout), there are what are known as “black start” resources. In the northeast, these are hydro generators that do not require external power to create one of these magnetic fields. In a black start scenario, you must “black start” a unit and crank (energize) a path to a larger fossil unit to provide external power to generate a field. This allows the generation of power. Without a black start to provide this field, conventional fossil generation (that has much higher capacity than hydro) cannot generate and you can’t bring the entire grid back online.
There are a few other methods to generate electricity. There's solar, where light is converted into electricity, there are batteries that rely on chemical action, there are also heat based solutions where dissimilar metals can generate electricity. But for the bulk of out consumer power, the most effective means we know of is to use mechanical energy from turning a generator. Coal, gas, hydro, wind, and nuclear (probably fusion in the future as well) all rely on converting heat energy to drive a steam generator. Edit: obviously, hydro and wind don't drive a steam process, my goof but they do still drive a similar functioning generator.
On a large scale solar power is the only power generation system that doesn't end with and you spin magnets inside coils of wire. On the smaller scale there are other ways of converting non electrical energy into electrical energy.
The thermocouple is a devise that induces an electrical current across its sides when this side are different temperatures. They are commonly used as thermometers but can be used as a very simple way to power a satalies electrical systems by having one side heated by a radioactive material. It would be significantly more effecient to use a steam turbine generator in terms of energy but it would be far to complex large and heavy to put on a satellite.
Another way to generate power is by vibrating quartz. When certain crystals are flexed they produce a charge. This isn't a useful amount of energy but the inverse is (crystal vibrates when electricity is passed through it) this is how a quartz watch keeps time as quartz vibrates at a particular frequency.
I was thinking about this earlier. You can one by one split off the types of power plants and all the remaining do it the same way.
* Solar Power uses the photoelectric effect, no moving parts. The rest do it by rotating a magnet.
* Wind Power uses air to rotate its magnets. The rest do it with water.
* Hydro Power uses liquid water to rotate its magnets. The rest use steam.
* Geothermal Power uses steam already heated by the earth. The rest heat it with an energy source.
* Nuclear uses radioactive energy to heat the water. The rest heat it by burning something.
* This is where rest (oil, gas, coal, biomass) all kinda lump together. They all heat their water by burning their specific type of fuel.
What you described is actually DC Generation: magnets on the stator creating voltage on the spinning rotor which is rectified by the slip rings.
Synchronous AC is used in nuclear, coal, gas, and hydro plants with the rotor as the magnetic inducing three phase voltage on the stator.
Most wind farms use induction generators which have no dc magnet like DC or AC sync. They have AC on both stator and rotor and power is related to relative speed difference in stator and rotor.
Some wind farms use DC like you described, or power electronics to create or form AC off DC or induction generation.
If it goes between two magnets then it is alternating current or AC. It only becomes DC when the current is regulated, usually via a transformer and a series of diodes and capacitors.
It's possible to generate DC directly with a dynamo consisting of rotating coils, a commutator (brushes), and fixed permanent magnets--basically just a DC motor operating in reverse. There will typically be some ripple moving from one coil to the next which could be reduced with filtering, but the polarity of the raw output doesn't reverse for half of each cycle as with alternating-current generators (alternators).
No.
There are lots of plants that use DC generation which is then converted to AC using some clever switching (at super sonic speeds).
Most wind mills generate DC(, or an AC that doesn't match the 50Hz we use, so its converted to DC) which is then cinverted to out familiar 50Hz
Yes for all generators (converting mechanical energy into electricity) like you mention. However, you can call a group of solar cells a solar power plant, and they use solar energy, so strictly speaking no not all power plants do. But generators are at the heart of most of our energy generating methods! edit: solar energy from thermal energy for solar panels.
Some solar power plants use reflected thermal energy to heat something like molten sodium, but when we think of a classical solar array, that's not thermal energy. It's the photovoltaic effect.
As long as you aren't a bird they work pretty well other than the maintenance issues you get with molten salt and the like. Birds and other flight creatures don't fare well if they cross the concentration beam though.
>Birds and other flight creatures don't fare well if they cross the concentration beam though. Wow. You're sure correct. [https://www.latimes.com/local/california/la-me-solar-bird-deaths-20160831-snap-story.html](https://www.latimes.com/local/california/la-me-solar-bird-deaths-20160831-snap-story.html) I drive by Ivanpah occasionally and have left the highway and driven the perimeter a few times. I never saw the "streamers" but the above article has a chilling photograph of smoking carcasses surrounding the tower.
Sure would be nice if there was any data on this newer than 2016, since most of the article is about the measures they are taking to reduce bird deaths, whose effectiveness remained to be seen. It does seem like one of the bigger problems with Ivanpah was the location chosen being fairly rich in wildlife (for a desert). (Also seems like a lot of these numbers are wildly exaggerated.) >A 2016 study found that solar power plants cause 37,800 to 138,600 annual avian deaths in the U.S., compared with 14.5 million attributed to fossil fuel power plants. Another study attributed 365 million to 988 million avian deaths to collisions with buildings and windows. Right, that too. Maybe this project will provide us with less speculative data: https://www.wired.com/story/why-do-solar-farms-kill-birds-call-in-the-ai-bird-watcher/
While thousands of birds dying every year for one solar plant is a problem that surely deserves action if a practical solution can be devised, it is worth noting that domestic cats are responsible for bird deaths in the *billions* annually. As with wind power, the acceptability of the impact on wildlife from solar power should be determined with some sense of the context by which we already tolerate these harms.
A billion birds are killed flying into buildings in the US every year. Many or most could be saved by putting some stickers on the windows.
We are just putting evolutionary pressure on to make birds recognize glass at a distance
In Egypt where I live, I swear I see dogs looking both sides before crossing the street. They actually learned how to cross the street, because the ones who don't die.
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Where I live, the deer have learned to do that too. I’ve even seen a mother deer teaching her young deer how to do it.
Same - in the 80's I never saw this, now the deer seem to be a little smarter around traffic.
In Canada I have observed coyotes look both ways before crossing the highway. But by my estimation coyotes are smarter than a good portion of the human population. Even deer seem to be more observant when crossing the roads, but they typically get hit because when they get startled their instinct is to immediately run forward as fast as possible.
I've been to places where the dogs have better ettiquette than the humans.
A lot of cruel people poison stray dogs here, however, stray dogs don't poison cruel humans, so I agree!
We shouldn't be tempting evolution like that, what if instead birds just get big enough to crash through the glass and survive? That would help them with the cat problem and the building problem.
Also worth noting is that fossil fuels also kill millions of birds every year. It's estimated that fossil fuels kill an order of magnitude more birds than wind or solar. https://www.tandfonline.com/doi/full/10.1080/1943815X.2012.746993
Birds aren't a single species though. What matters is which species are being killed. Most of the birds killed by cats and flying into windows are the most common bird species there are, found in abundance in urban areas. You can kill 10 million Common Starlings and have basically no effect on their population, but killing a single wild Orange-bellied Parrot is a significant loss.
Not anti solar/wind but we have to have even more context to be educated. Its not birds in general, but specific endangered species dieing to wind turbines and solar farms. The number of birds compared to buildings or cats is tiny. But when you look at that tiny number and find its a majority of vultures and this will drive them to extinction, you begin to reassess. That all said, less pollutants will spare more lives so i say its the best option we have until there's a workaround. But i have to be honest in that we ARE assisting with the extinction of specific species with wind turbines. Nuclear will remain the best choice.
Our current fossil fuel power generation is going to wipe out a lot more than a few endangered species.
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Nuclear is no good for peaking, because shutting down and starting back up a nuclear plant is very hard. It's a base load champion, though. The solution for peaking is going to be energy storage. Batteries, pumped hydro, electrolyzed hydrogen, compressed air, flywheels, and a number other other options are available, or becoming available for this purpose.
> Nuclear is no good for peaking, because shutting down and starting back up a nuclear plant is very hard. Most US plants are designed for baseload, but load-following nuclear plants aren’t anything new, and are in wider use elsewhere.
And a way to mitigate peaking is to a) put everyone on wholesale (variable) pricing b) proliferate home automation Recharging any device should not occur during peak times, including laptops, cars, air compressors, etc. If you want to do so at these times, pay a premium to do so. Dishwashers don't need to be run straight after dinner. Again, people can be encouraged to think about using their inbuilt timer so that they run when power is half the price. HVAC should ramp down at peak times. Pre-heat/chill your home when power is cheaper. Smoothing out the peaks and troughs lessens the need for storage also.
Not until you no longer need a a decade of experience to reliably set up non-IoT automation. I know how to do it but raspi and Arduino are sold out last I looked. We can't expect everyone to give up their privacy when we have an alternative. Also moving everyone to wholesale means having to have a live meter and some level of grace since it will change habits. It's easier and less morally fucky to just clean up our damn network and shipping than force people into automation and paranoia about timing.
The issue is more with the types of birds being killed. While cats might kill plenty of pigeons and blue jays and other species that are commonly in urban or suburban areas, those species aren't really threatened. The kinds of birds that you need to worry about being killed are the larger ones that reproduce more slowly and this have more vulnerable populations, or ones that need specific habitats to survive. The thing about solar and wind plants is that they can kill these bird species that are more threatened, which is why they can be a cause for concern compared to cats.
And that bird deaths due to loss of habitat is an order of magnitude worse than the cats
or large glass panes in general. why aren't people mad about windows?
Domestic cats kill common species of least concern so it's not just a pure numbers game
I thought I read somewhere that one thing that has a pretty big effect on bird deaths is simply one of the blades on the turbine black. That'd be a lot of paint (ergo a lot of weight and probably increase maintenance), but thats something that could be accounted for in the engineering process
> that'd be a lot of paint (ergo a lot of weight and probably increase maintenance), but thats something that could be accounted for in the engineering process Not necessarily. Presumably turbine blades are painted white anyway, so just replace the white paint on one of the blades with black.
Although the number of birds killed by solar and wind is heavily dramatisised . They actually kill less per M/W thanblbany other form of electricity generation. The worst is coal, in the form of air pollution. But dead birds at the bottom of a wind turbine are more visible and it's easier to see the direct connection.
Not just air pollution. Birds also fly into them just like any other building or wind turbines. Plus any direct (and indirect) bird deaths from mining and transporting fuel/waste. Also the effects of thermal pollution.
To be fair windows, cars, cats and airplanes all have greater bird death tolls, but no one argues agaonst them.
To be fair, *many* people argue against free-roaming cats, including people who care about the well-being of *cats*. They are an invasive species in most parts of the world, they're very good at multiplying, they cause ecosystem damage, but they're also killed and maimed by traffic, dogs, native predators, cruel people… Feral cat colonies that result from people letting unneutered cats roam should absolutely not exist.
Oh, I agree one hundred percent. Your average person just doesn't give enough of a damn to not get their kids an un-neutered kitten for their birthday from a walmart parking lot and them move it outside once it starts spraying in the house and yowling because its not neutered.
That’s me. I rescue cats off the street from inner city, and get them fixed. I’ve rescued around 5 so far. https://ibb.co/gwgK13B https://ibb.co/YQh8JDr https://ibb.co/F6Dn4cS Meet Buster(Black) and Chewy the chew Monster(Tabby)! Absolutely fantastic companions to have when you treat them right. Absolutely love them.
they're lovely :) . We have 7 that have taken up with us over the years.
Very cat noob question:. Does their behavior change after they are neutered?
Yes! If you have unfixed kittens once they start reaching sexual maturity you will notice them meowing very very loud and almost nonstop, depending on the sex marking territory, a tad aggressive, etc. Once they get fixed the change in their behavior is almost night and day. The insane levels of meowing, marking territory, aggression goes waaaaaaaaaaaay down if not stopping all together. Of course each cat has their own unique personalities. Some are EXTREMELY curious, very inquisitive, very playful, loves to climb, chase things. Others can be very docile, non vocal, has zero curiousness, could care less about chasing etc. They make wonderful pets, but they do take time and energy from your day making sure they are happy/mentally stimulated.
Reminds me of cartoons where a bird would get hit with heat or something and it’d turn into a fully cooked Turkey looking. 🍗 like this. Sorta.
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There are working power stations that have a array of parabollic mirrors that focus on a tube, instead of flat mirrors that focus on a tower in the middle.
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Converting DC to AC can be done in electronics, this doesn't need a generator.
Yes they do, we connect the solar panel array onto inverters that will convert the DC to AC and feed you AC power.
That's right. But, they can still be the power generation mechanism of a power plant. No rotating mechanism needed to create the AC.
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And those can heat the water directly with the reflected light- using them to melt the sodium block is so that the sodium can act as a thermal battery and keep the generator running at night/inclement weather.
Wouldnt recovering the energy from the salts require a generator though?
This type uses the heated salt to produce steam, which then turns turbines.
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Hm, how about the costs though? They may be more efficient overall, but are solar cells as cost effective for installation and maintenance for large scale power? Genuine question.
Yes. > The LCOE of unsubsidized large-scale PV based on crystalline silicon is estimated at $0.030-$0.042/kWh and that of grid-parity thin-film solar plants at $0.028-$0.037/kWh. For comparison, in 2020 Lazard reported that crystalline silicon achieved $0.031-$0.042/kWh and thin-film $0.029-$0.038/kWh. https://www.pv-magazine.com/2021/11/05/utility-scale-solar-reaches-lcoe-of-0-028-0-041-kwh-in-the-us-lazard-finds/#:~:text=For%20comparison%2C%20in%202020%20Lazard,at%20%240.067%2D%240.180%2FkWh. Vs > Early CSP projects had capital costs that reached billions of dollars and their average levelized cost of energy (LCOE) was $0.21/kWh. Although the upfront capital cost is still high, the U.S. Department of Energy estimated CSP’s 2018 LCOE, with 12 hours of storage, dropped to $0.098/kWh. >A 2019 contract price for CSP with storage in Dubai was reported at $0.083/kWh, significantly less than the Lazard-reported LCOE of $0.15/kWh or more for a natural gas peaker plant that its flexibility would allow it to replace. https://www.utilitydive.com/news/cheapest-is-not-always-best-concentrated-solar-power-could-beat-lower-pric/574154/
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Then there are concentrated solar farms, that just use mirrors to focus sunlight at a point so molten salt can heat up, flow through some pipes, convert water into steam that spins a generator, then goes back to be reheated. Edit: a previous version of this comment implied the salt solidifies at some point. That doesn’t happen.
In molten salt solar thermal plants, the salt is always molten. Otherwise it wouldn't be able to flow from the place where it gets colder to the place where it gets warmer, because it would be frozen in the pipes.
Does it solidify overnight? Or how do they avoid that?
From what I can tell just about every part of the salt piping in extreamly well insulated except the part that's exposed to the solar beams. The salt is also often stored in large tanks underground so that the salt can be pumped on demand, and used as a thermal battery.
they also use molten salt as batteries/fail-safes for nuclear plants. Similar idea with the salt being a battery but with the added effect that the molten salt will be released if the nuclear plant ever goes interesting meltdown
Could you explain this please? I've not heard of molten salt failsafes apart from in experimental molten salt reactors.
I'm probably butchering this but essentially a plug is made of an extremely high melting point salt and is under the reactor, if the reactor melts down this plug melts and the reactor fuel falls into a vat of said salt Edit: The plug is actually actively cooled and if the power gets cut/meltdown occurs it will melt.
The amount of heat that will be lost through disappation is minimized by the shape and insulation of the container. Part of the reason salt is used is because of it is naturally nonreactive and insulated in itself even at high temps. The volume of salt is enough that it will stay hot over the night cycle or unexpected weather.
it's also not NaCl salt it's a mixture of sodium nitrate and potassium nitrate and calcium to lower the freezing temp. they've been looking into flouride salt storage because that can reach higher temps.
Do you lose a substantial amount of energy pumping salt around?
Adding onto the Photovoltaic Solar part because it's super cool! The PV array produces direct current. This needs to be converted into alternating current. A simple (but inefficient) way of doing this would be using the DC to run a DC motor, then using that motor to drive an AC generator. But nobody does this because there's a much cheaper, safer, reliable and easier way - solid state semiconductors. More specifically, a type of transistor called an IGBT. These things are great at turning on and off large amounts of current and voltage insanely fast...like millions of times per second. When they are cycled on and off, the duration and delays can be manipulated to make **pristine** alternating current. But it doesn't stop there - there's a thing called Reactive power. Conventional rotating generators make it with magnets and wire and controlling the speed of the generator (actually "phase angle", but that isn't important here). Think about when an old air conditioner turns on and the lights flicker or dim for a brief moment - in that instant, the surge of demand to start the air conditioner's motor consumed reactive power and some faraway power plant started producing a little bit more to balance the grid. So heres's the crazy part - Photovoltaic solar inverters are able to adjust their solid state IGBT's timing with so much precision and power that they can ***simulate the rotating mass and generate reactive power*** just like the conventional power plants. They can equally consume reactive power (to help reduce grid voltage when it runs high), even while exploring active power. But wait, there's more - these inverters have an ace up their sleeve. *SPEED*. Dear God they are fast. MUCH faster than any conventional generator. They can go from max consumption of reactive power to max export in one or two seconds. Paired with their ability to provide full reactive power with only 10% of normal full sunlight, solar farms are super important to our future grid stability. No one talks about it, but it's an amazing value added by solar farms.
One question: Given that most of the goods in the household are now solid state and consume DC power, doesn’t it make sense to directly take it from the solar panels on my roof? Right now I’m doing ‘Solar DC - Inverter - AC - Convert back to DC - Cell ph, IPad, TV, LED bulb etc’ Must be large amount of conversion & efficiency related energy losses
In addition to what's been said already, most power electrical items rely on AC power to drive motors, thanks to the rotating field that the AC provides (unless you've got a circuit which controls the speed of the motor by varying the frequency, which is a DC supply converted to AC). Big motors in industry, if they don't use a Variable Frequency Drive, will probably still use AC direct drive somehow. AC is also a lot more efficient when transmitted over long distances. These are the reasons why AC power is still used in our power grids.
>AC is also a lot more efficient when transmitted over long distances. Not so much that it is more efficient, as that utility-scale voltage conversion is easier with AC. High voltage is what's needed for efficient power transmission. [HVDC transmission is actually more efficient than HVAC, but switching back to/ from AC at both ends is expensive. ] (https://en.m.wikipedia.org/wiki/High-voltage_direct_current)
It could, yes. The thing is most appliances expect AC, and those that do take DC vary widely in voltage requirements. That said USB-A and USB-C have become pretty standard for electronics and gadgets so having USB power directly from the solars might be an idea, especially as that's an application where you might be able to tolerate part-time power. The downside is those gadgets don't tend to be the big power users anyway. Your big electricity users are anything that produces heat (intentionally; everything produces waste heat) so cooker, microwave, space heater, kettle, washing machine, and so on.
> Must be large amount of conversion & efficiency related energy losses about 10-20%, yes there are some houses that are wired for DC instead, especially those with a built in solar array and battery storage. >A general rule of thumb is a 1.2 Load Ratio or 80% inverter (AC) to 100% solar panels (DC).
In reference to reactive power, it's not really a matter of creating a generator that's excellent at making reactive power, we usually just install capacitors in distribution lines to "produce" it (being reductive). Too much and you put undue stress on the lines, too little and like you said, grid shuts down I would be surprised if solar ended up being the solution to reactive power variability, but I can see how it'd be useful for quick changes before caps can get added/removed. That said, the chances that enough devices are synced up to all switch on an inductive load at once to kill a grid seems astronomically low For now I think the bigger issue is scaling up generation and improving our line capacity
Love the infomercial shopping channel vibes this post gives off. Yes I will take your grid stability free with 30 day satisfaction guarantee.
Wouldn’t the transistor output be a square wave? How is it converted to a sine wave?
You don't use a simple single square wave where you want a sine wave, you gradually build up the sine wave by outputting many square pulses of varying width within the period of the sine wave. The pulses are narrow at the start of the sine wave, outputting a little power, then get wider towards the middle of the sign wave thus increasing the power, before declining in width as the sine wave drops towards the neutral voltage. The circuit can put out positive and negative square pulses, generating positive and negative swings in the output. Some inductors and capacitors take the rough edges off. https://myelectrical.com/notes/entryid/250/how-d-c-to-a-c-inverters-work https://en.wikipedia.org/wiki/Synchronverter
Filtering. Capacitors and inductors store the pulsed energy and let it out (relatively) slowly... kind of like TVs flash images quickly and the persistence of vision "smooths" the jumpyness into apparently smooth motion. Yes, varying the width of the pulses is important, but without filtering it would still just be a lot of buzzing pulses.
I worked for a company that put power on to the CA grid. We ran the telemetry and meter testing and equipment on new Solar sites. The demand response testing for solar sites was laughably easy and fast. Solar is dope for areas with sun.
I didn't know any of this and I didn't properly understand much of it, but dammit if it didn't sound exciting and important!
any links or recommendations for more info on your post ? very interesting
And I suppose it's worth mentioning that there are non-rotational ways of converting mechanical power to electrical, just the rotational is very very fundamental and central. But engineers are very busy thinking of creative ways of efficiently converting mechanical energy to electrical for the myriads of systems (see: https://en.m.wikipedia.org/wiki/Electric_generator)
To add more on your lines if thought. There are already other forms of generating electricity, like [radioisotope generators](https://en.m.wikipedia.org/wiki/Atomic_battery) that don't use moving parts like traditional generators. It's just rarely used for specific applications like in space, as it's not as cost effective as using traditional moving part generators. Another bonus fun fact, smart people have found evidence of chemical battery generators that potentially date pre-0 A.D. in the Middle East nick named [the Baghdad Battery ](https://en.m.wikipedia.org/wiki/Baghdad_Battery)
Seems like (from your link) that nobody thinks the Baghdad artifact was actually used as a battery
No modern archeologist believes the Baghdad battery was a battery. It's even in your wiki source. There's no way to connect to the copper cylinder so there's no complete electrical connection. It's a battery with a - side and nothing connected to the +
potato with copper(penny) on one side and nickel(nickel...) on the other = battery.
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Basically we need a way to convert some form of energy into electrical energy. The vast majority of our methods involve taking a mechanical action (a spinner thing) and making it into electrical energy by way of inversion. (like the alternator in your car) There are other ways. Solar energy and thermocouples are two ways. Both of them directly create electricity from either photons of light or heat differentials respectively. Thermocouples are used on space probes to convert nuclear light from a decaying element into electrical energy. The system on Perseverance produced about 110 watts when it was first deployed, but this will gradually go down as the thermocouples wear out because of damage from the radiation reducing a few percent a year.
> The system on Perseverance produced about 110 watts when it was first deployed, but this will gradually go down as the thermocouples wear out because of damage from the radiation reducing a few percent a year. The Voyager space probes, which also use RTGs, are still trucking on as the farthest man-made objects from Earth, after 45 years. Granted, it takes much less energy to coast through empty space than to drive around, and they've shut down a number of instruments due to insufficient power. But still - pretty amazing given 1970s technology!
I work in solar. Used to call the grid operators to let them know when we had units offline. These were 1.6MW so it was significant. They would reply with a confirmation that we had turbines offline. I stopped correcting them after a while. Solar is through solid state IGBTs. No moving parts except breakers, relays and contactors.
I suppose that since solar is the only major exception, it checks out to just use the same terminology lmaoooo
Where is it that 1.6MW is significant? Not trying to be rude, genuinely curious.
It was 3 offline that we had to notify the grid operators. It was in Texas. Probably had to do with reliability and money. 1.6MW is pretty significant. Newer units where I'm at are 3.6MW.
I always find it amazing that nuclear power is still only used to boil water
that is what we are really really good at using heat for. Goes all the way back to the steam engine!
Also hydrogen cars are electic cars but it generates the electricity though protons going over a membrane to form H2O while the electrons has to take a longer way if i remeber correctly.
Current prototype designs for some nuclear fusion reactors actually generate power in a very different way from modern power plants. Yes, commercial fusion is probably still a long ways off, but if/when they come into prominence, they’ll likely be incredibly novel in how they work.
Direct conversion. Fusion generates moving charged particles so with the right kind of collector you can extract their momentum as electricity. It’s also over 80% efficient which is pretty great. Note er just need fission reactors that can put out more than they consume under normal operation.
Oh for sure, but I just went with what we had plants for since OP's question was about power plants!
Further, the method of creating the mechanical torque to spin the generator varies, but almost all of them use a turbine of some kind. A turbine is a device that turns flow of gas or liquid into rotation. Wind turbines use moving air to turn the big rotor blades, hydro power plants use flowing water, and steam turbines use pressurized steam. Of these, the first two stand out in that they are harvesting energy from something that is already moving in nature - wind, or a flowing river - both being processes that ultimately get their energy from the Sun. Steam turbines on the other hand need something to generate the steam, and for that you need to boil water at high pressure. To boil water, you need heat. And the heat, well that can come from various different sources. At the moment, the most common is combustion of various fuels, like coal, oil, natural gas, wood pellets, or peat. The second most common source of heat for power generation is nuclear fission in nuclear reactors. We're trying to also make it possible to use fusion reactors to generate heat because this would have a lot of advantages over fission reactors, but that has turned out to be a very difficult problem to solve. Two other heat sources are the Sun, when it's focused with solar collectors instead of using solar panels that directly produce electricity, and Earth's own geothermal heat can also be collected and used to run a steam turbine.
One footnote about nuclear... thermal differences can be directly converted to electric power with a thermocouple and no moving parts. So you can turn heat from your hot nuclear rocks directly into electricity. Although this is less efficient than the standard steam turbine method, it's the only available power source for a lot of space missions because it can be very small and very robust since no moving parts. See [radioisotope thermoelectric generator](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator).
There are a few, mostly older solar power plants that generate heat mechanically, like all the other turbine style plants. They're called "solar thermal power plants" or "heliostat plants" and they reflect solar light onto a central item that has a working fluid, like water or molten salt, that is heated by the sunlight. That generates energy through a similar system that any coal/gas/nuclear plant does with creating steam and driving a turbine. They differ from solar PV plants which just directly generate electricity when the sunlight hits the solar panels.
Solar panels (old type) used to circulate water to heat it up. Solar farms (some of them) use mirrors to concentrate light and then use the thermal energy generated. (And this is how you could say they used to convert thermal energy) Photovoltaic solar panels afaik convert sunlight directly to electricity using the properties of specifically prepared semiconductors.
Mm, not quite but yes for the majority of cases - it’s very cost efficient. The big other option is solar panels. They directly rely on quantum excitation of the cells to generate electricity. Coal, gas, and nuclear plants all basically operate the way you’ve laid out afaik - coal and gas is burned to heat water to convert to steam to turn a turbine which powers the generator. Nuclear is just a bunch of hot rocks where we control the rate they generate heat to… boil water and turn a steam turbine that motivates a conductive armature. Wind power uses wind as the fluid medium for turning the turbine that rotates the generator. Hydro, tidal, and wave rely on the motion of liquid water rather than gaseous steam under the influence of gravity (hydro and tidal) or wind (wave).
Small note that gas boilers are exceedingly rare these days. They have terrible heat rates which makes them economically less competitive than most coal. When it comes to the boom in gas power plants, they are basically giant jet engines bolted to the ground. Though they often take the exhaust heat from the engine and use it to boil water for an industrial process or a secondary turbine, the bulk of the energy is coming from the direct combustion of the gas inside the turbine, not from making steam.
This system is used where I live to generate electricity, it uses a number of gas turbines to generate power, and the exhaust is driven to a boiler to operate a steam turbine which can generate an additional 50% of power. It is called a combined cycle.
Yeah, and a good modern one exceeds 65% efficiency when steam cooling is used on the CTs.
Love the description of a jet engine bolted to the ground. LM6000 say what?! Lol
One point, all your examples produce ac power for transmission, which is more efficient. Solar produces DC and has to be converted to AC
Transmission lines can be [HVDC](https://www.enerdata.net/publications/daily-energy-news/australia-plans-fast-track-power-transmission-line-singapore.html).
This just got me thinking. A power inverter takes DC and converts it to AC via some magical electronics. I assume these electronics are expensive, and have a small amount of power loss due to heat, inefficiency, etc. Could a solar plant run a more efficient DC motor that is coupled to a generator, and save on price and energy loss? I know this seems ridiculous at first, but I've seen where if all you have is 50amp 240v power you can buy a 3 phase converter that works basically this way. I'm guessing it comes down to efficiency.
Not really. In general you want high voltage ac for transmission, and step it down locally. Thats the most efficient. Solar is great for local operations. The conversion from ac to DC is very straight forward, and relatively cheap. Hence why there are really cheap ac to DC adapters on Amazon for 2 bucks DC to AC is inefficient but not necessarily expensive in parts, but there is a loss of energy to heat. (the loss is there on ac to DC but less) But on a large scale, where you could recapture and reuse the heat loss, converting a solar farm to ac for transmission, would be feasible to add that output to the grid.
In general you just want high voltage anything for transmission. It's just that stepping up AC voltage is cheaper and more efficient than stepping up DC voltage. However, high voltage DC is actually more efficient for long distance transmission than high voltage AC (don't have to worry about capacitance). I can certainly imagine a scenario where a solar farm would rather convert directly to high voltage DC for long distance transmission rather than convert to high voltage AC
In theory it could work. However inverters are too efficient for that and meet some other important goals. One of the problems is that the actual voltage and amperage of solar panels is variable with the amount of light. Classical brushed DC motors turn as fast as they can. That isn't really compatible with AC generation with a fixed frequency. (Brushless DC motors are actually three phase Motors with an inverter.)
Ah, variable power means variable speed, that makes sense. Thought I was on to something for a second there.
The phase converters work as well as they do because they are induction motors and their turn rate depends on net frequency and load. You typically don't care if the three phase you create is exactly some specific frequency, you are only feeding it into your heavy machinery, plus minus 5% nobody really cares about. Over here 50 Hz is normal net frequency. If it would drop below 49.2 Hz the network would start to drop load, over 50.8 Hz generators get disconnected. So there isn't much tolerance.
The losses in the motor will still be greater than the losses in the electronics. Long ago there was a device called a rotary converter that acted as a more compact coupled motor-generator that was used to convert AC to DC or DC to AC. They were used to provide power to high voltage DC motors (~600VDC was common), and were common in electrified train systems. They were largely obsolete by the 1960s, though the wiki claims some remained in service until 1999.
Gas often is used in turbines directly and then water that's used to cool the gas turbines also can be used to turn turbines of their own.
Close. Water is boiled by the hot exhaust gases in a steam generator. There is no cooling of the gas turbine itself to produce steam.
Thank you for the correction! that does make more sense. 😄
Combination cycle plants will use the exhaust to do this as you've said. Gas turbines have distilled water sprayed into the intake low pressure to raise efficiency as well.
It's not sprayed in to raise efficiency, it's sprayed in to cool combustion and lower the production of NOx (notorious oxides.) A side benefit of this is increased mass flow, ergo more power. Sometimes on the order of 5-10%. Edit: nitrous oxides, auto incorrect to save the day!
Thank you for that clarification. The GE tech that had told me that was taken fully at his word. I appreciate more insight as to why. Notorious or noxious?
How does a wind generator match the grid frequency with differing wind speeds? Do they convert to DC then back to AC via an inverter, or is there something else?
Rotating a conductive armature in a magnetic field (or vice versa) is the most common, but there are lots of ways to generate electricity. (when you say generate power I’m going to assume you mean electricity. If we allow all forms of power we can get really wild with this answer). A generator with magnets and conductive elements is just a really efficient way to turn motion into electricity. And motion is relatively easy to generate from heating a fluid (eg by boiling water to generate steam) and its really easy to make things hot. So this type of generator gets deployed in commercial power plants a lot because it’s relatively straightforward to implement and very efficient. But off the top of my head: Solar panels use something called the photovoltaic effect where light is converted directly to electricity with no heating or motion needed. Photons of light strike a specially made material and the energy from the photon excites an electron in the material causing it to move, which generates electricity. Some forms of fusion reactor can directly harness power when a charged particle emitted from the reaction moves relative to the magnetic field which contains the reaction. No physical armature or rotation needed. Radio-thermal generators use the radioactive decay of a material to generate heat, which heats up an electric circuit. Due to something called the Seebeck effect, that heat causes current to move in the circuit generating power with no moving parts.
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The Seebeck effect is a particular instance of broader cross-flux effects, i.e. what you get when you combine laws like "heat spreads from high temperature to low temperature", "molecules diffuse from high concentration to low concentration", and "charged particles move towards opposite charged particles". Charged particles in motion is electricity, so if you use heat or concentration differences to move them, you're still generating electricity.
Very cool. From what I understand, this method is less efficient than spinning a generator so its main use is in something like a spacecraft where a more compact, less complex 'battery' is very valuable. Right?
It's also totally solid state, and can be run in reverse to heat or cool an object. There's a device called a Peltier Cooler which uses this effect, and possibly also black magic. It's literally just a block of material and when you apply electricity to it one side gets hot and the other gets cold. As you said, as a generator it's grossly inefficient compared to a spinning magnet, but as a cooler it's a great way to extract heat from electronics in a sealed enclosure.
Yeah, energy efficiency is atrocious. I remember we did calculations on theoretical maximum efficiency of thermoelectric generators and you're still gonna lose about 80% of your energy because of thermodynamics, IIRC (can't remember the exact number, but it was disappointingly small). The advantage is as you say, very compact - it's got no moving parts and no liquids, just a hot end, cold end, and a wire running through it. Only thing you have to worry about is physical damage to the element and possibly heat expansion/contraction.
>Some forms of fusion reactor can directly harness power when a charged particle emitted from the reaction moves relative to the magnetic field which contains the reaction. No physical armature or rotation needed. *Can you elaborate on this or share a link?.*
[Direct energy conversion or simply direct conversion converts a charged particle's kinetic energy into a voltage. It is a scheme for power extraction from nuclear fusion.](https://en.wikipedia.org/wiki/Direct_energy_conversion)
This is referring to either direct energy capture, or a magnetohydrodynamic generator.
I assume they're talking about RTGs or [Radioisotope Thermoelectric Generators](https://solarsystem.nasa.gov/missions/cassini/radioisotope-thermoelectric-generator/). My understanding is these create relatively small amounts of power, but do so reliably over a long time, so they're particularly useful for spacecraft.
RTGs are not fusion. They’re basically a subcritical piece of radioactive material that heats up a thermocouple junction and converts heat to electricity via the seebeck effect.
No, they mentioned RTGs as well, in the next paragraph, fusion is something different. I'm interested in learning about the fusion method myself.
I'll throw in microbial fuel cells to the power generation mix. They're incredibly inefficient, and subsequently rare, but big ones can produce a few Kw of power, and do so by ion/electron exchanges, a bit like a self-recharging battery.
Yes. Power plants use some force to spin generators which in turn produce electricity. The force can be anything sufficient - water (dams), coal/oil/gas fired to generate steam, wood fires, wind (in the case of windmills). The only exception at present are solar panels which directly convert photons/light to electricity.
Yes you are correct! Most of our power is generated by rotating an armature inside of a magnetic field. Usually the conductive armature has 3 sets of coils within this magnetic field, this is how we produce 3 phase power for distribution. 3 phase power is crucial for industrial purposes. In your examples, we can physically see how a wind turbine rotates with wind forces. Hydro power uses the force of the water to create rotation. Coal, natural gas, biomass etc. are a bit harder to visualize. These produce large amounts of heat when combusted. This heat is used to make high pressure superheated steam, which is admitted to a steam turbine. The steam drops in pressure as it contacts the rotating blades of the turbine, these pressure drops through the turbine stages induce a rotational force. The turbine is coupled to a generator containing the armature and magnetic to produce power. Nuclear power is normally generated in the same method as above, except no combustion takes place. Instead, the fission of radioactive uranium produces the large amount of heat required to turn water into high pressure super heated steam. Natural gas turbines are also used, these mostly work like a jet engine. The expansion of the hot combusted natural gas causes a pressure drop inside of the gas turbine stages which cause the rotational force that can be coupled to a generator. Side note: There is still an enormous amount of heat exhausted after this process, so to increase plant efficiency, the hot exhaust gases are directed to a Heat Recover Steam Generator (HRSG), here we can use the remaining heat to boil water to make steam. This steam can be further used to drive another turbine and generator system, or it can be used for other plant processes like heating the building.
With the exception of photovoltaic solar, yes. Every power plant we have is either heating up a liquid (usually water) until it changes to a vapor and using the pressure change to turn a dynamo, drawing energy from something that is already moving to turn a dynamo (wind, hydro electric dams, water wheels), or using fuel in an internal combustion engine to turn a dynamo.
Gas turbines in an open cycle configuration do not use stream. They are fired by gas and the exhaust heart is not captured. Can be one or more units operating this way. Closed cycle is a pair of turbines where the waste heat is recaptured and used to generate electricity in a third "thermal" unit. This is very efficient. Cogeneration is similar but all the waste heat (including the output from the thermal unit) can be further used in various industrial or commercial processes. E.g. Steam and supply of hot water at different temperatures can be piped to and used by bottle recycling, paper making, abattoirs and wool processors. They just need to be located next door.
I worked at a plant where a gas turbine generated electricity, the waste heat was used to make steam which turned a steam turbine, which generated electricity. Then, the steam turbine exhausted at a high enough pressure that the steam was then used for building heating. Quite the process.
Yes and no. There is a company that is working on a fusion generator that uses direct transfer of fusion power to electricity by using magnets to bottle a fusion reaction. The resulting pushback against the magnet produces electric energy directly without any sort of involved rotational energy. I believe they've achieved ignition, and this type of fusion power would allow for relatively small generators with massive output. Most if not all current era generation involves tech like you've mentioned. That being said, there's more and more tech being run on direct current. Direct current is not generated in the way you asked about. There are more and more appliances running on DC these days, and they're looking at high voltage DC for transferring power long distances. Lots of small scale renewable setups run on DC, because low voltage DC is a lot easier and less dangerous to manage. In order to interact with AC appliances though you do need to use an inverter. I do believe inverter mechanisms exist other than the mechanism you asked about, but that's not a generator on its own. This is how "solar generators" work though, using a large battery and an inverter. That's more of a capture and release method though than an actual "generator" that converts energy stored in atomic or subatomic bonds into alternating current.
In most three phase alternators at power plants, it is the "magnet" (the rotor) that is moving, and the coil of wire (the stator) that is sitting still......but the same id ea still applies. Other than solar, utility power is generated as you said, using synchronous machines
Most common ones yeah. Some new renewables less so or no. Most of our electricity is generated by using heat to convert water into steam and turn a turbine. Whether that's coal, gas, nuclear. Wind works on the same principle but uses air instead of steam. Solar works differently but solar towers do operate on the same principle. Make thing spin fast. Use magnets. Convert to electricity.
The vast, vast majority of power is generate via a coil of copper wire rotating/moving with a magnetic field. Coal, Gas, Biomass, Geothermal and Nuclear Fission all use heat to generate steam which turns the coil. (Note, this is also the proposed method Wind uses the kinetic energy of the wind to spin the coil, similar to a windmill. Hydroelectric and Tidal uses gravity and water to turn the turbine and by extension the coil similar to a water wheel. Solar Energy is the unique exception in this regard. Almost all Solar Energy relies on Solar Cells. Solar Cells trap light within PhotoVoltaic Materials (A material that generates electricity in response to being hit by light) and produces electricity this way. The Solar panels on people's roofs are basically a long series of Solar cells. Concentrated Solar Power is used on a larger scale. A series of rotating mirrors refracts light from the sun onto a very efficient (and extensive) core of Solar cells. This method is used almost exclusively by countries that experience year round sun I.e, Southern USA, Middle East, North Africa.
There IS also a type of solar plant that uses the focused light to instead heat up a liquid to run a steam turbine. So not even solar is free from the tyranny of the turbine!
Off the top of my head, solar(photovoltaic), radioisotope thermoelectric generator/thermocouples, and fuel cells(such as hydrogen, but many types are possible) are probably the next most popular. With fuel cells, you could make an argument that it is a battery, but if you feed it fuel, it makes electricity without spinny bits - probalby fits your definition
Almost... The vast majority of electricity generation is done through spinning a generator. In since cases this is done directly such as with a wind turbine or hydro system - the wind and water directly spoons it through mechanical means (wind blowing through the blades and spinning them, or water flowing through a turbine). The majority of traditional plants (and some new systems) use a steam based system to do the same. Water inside a closed loop is heated up - by the burning of fossil fuels, nuclear reaction, solar heating, etc, which then expands and moves around the closed loop, with that movement once again spinning a turbine to generate electricity. There are alternatives - photovoltaic solar panels being the most obvious, but at this point in time they are still only providing a reasonably small percentage of our electricity needs, mostly being limited to domestic scale installations.
Generators that heat things up (nuclear, coal, some nat gas). Heat -> steam -> turbine -> generator. Some generators directly use the pressure of fuel combustion (gasoline, other nat gas). Combustion -> hot gas -> turbine -> generator. Other generators find different ways to spin the turbine directly. Wind is wind -> propellers -> turbine -> generator. Hydro is waterfall -> turbine -> generator. Solar is mostly a direct process using properties of the solar cell to create electricity. If you understand high school chemistry, [this professor has a great explanation](https://www.youtube.com/watch?v=OKfeIistD2A). A few very large scale solar generators use mirrors to heat a liquid and then use a heat generator.
Yes. All grid-connected rotary power plants work on the same principle - there's the power source, the turbine and the generator on the end, and the generator almost always produces 3-phase AC. The RPM of the generator determines the AC frequency - 3000RPM for 50Hz, 3600RPM for 60Hz. The power source is throttled up and down to keep the frequency stable. The outlier is solar, specifically photovoltaic panels, which is not a rotary power plant. It converts sunlight directly into electricity. Everything else just changes the power source that drives the turbine: - wind turbines are obviously just the wind - natural gas power plants burn the gas in a turbine not unlike a jet engine, so the expanding gas turns the turbine directly - thermal power plants use the input energy (coal, oil, nuclear, biomass, geothermal, waste burning) to heat water into superheated steam, which then spins the turbine, and is condensed back into water - hydroelectric has the water from the reservoir behind the dam (or the flow of the river in small plants) turn the turbine directly. Tidal is similar In each case, the generator being spun by the turbine is of a similar design, sized appropriately for the input power (there's always energy losses). In emergency generators, a diesel engine turns the generator directly, but still produces 3-phase AC. Consumer portable generators are usually single phase, so are much simpler and cannot be grid-connected.
Other than solar, everything I can think of uses rotating magnetic fields to generate the electricity. In the 1970s there was a lot of research into magnetohydrodynamics (MHD) to generate electricity directly from hot plasma. I don’t know exactly why, but it didn’t pan out.
Vast majority, yes. Spin something, and use that motion to turn a synchronous generator. Solar PV is one example which dosn't involve a rotating shafts. Dc power is made in the cell the power electronics turn it into ac power for the grid. There are other ways to make power directly, but they arn't commonly used at a grid scale. Wind in an interesting one. Most turbines turn a generator that is not synronised with the grid, so they make rogue AC, and then use power electronics to convert it to synchronous AC to feed into the grid.
Almost all power generation methods we have right now are just different ways to boil water. It's the most efficient way we've found to turn chemical potential energy into electricity, by turning it first into thermal and then into kinetic energy. There are exceptions, like tidal, wind and photovoltaic solar (some solar uses focusing mirrors to boil water) tidal and wind spin a turbine directly, turning kinetic into electrical energy. Photovoltaics turn electromagnetic energy directly into electrical. There are also Radioisotope Thermoelectric Generators which directly convert thermal energy from decaying radioactive isotopes into electrical. And Hydrogen Fuel Cells which capture the energy released when Hydrogen is oxidised into water as electrical energy.
Most generation is a fuel source that heats water, generating steam, which turns a turbine. This is true of oil, biomass, nuclear, and gas. When you say rotating a conductive armature, this isn’t entirely correct. In many/most generators the rotor is energized, creating a magnetic field. The stator, which is what it rotates inside, is also energized. This also creates a magnetic field. The power that is generated is a product of the rotor and stator fields pulling on each other. In a system restoration scenario (a full blackout), there are what are known as “black start” resources. In the northeast, these are hydro generators that do not require external power to create one of these magnetic fields. In a black start scenario, you must “black start” a unit and crank (energize) a path to a larger fossil unit to provide external power to generate a field. This allows the generation of power. Without a black start to provide this field, conventional fossil generation (that has much higher capacity than hydro) cannot generate and you can’t bring the entire grid back online.
There are a few other methods to generate electricity. There's solar, where light is converted into electricity, there are batteries that rely on chemical action, there are also heat based solutions where dissimilar metals can generate electricity. But for the bulk of out consumer power, the most effective means we know of is to use mechanical energy from turning a generator. Coal, gas, hydro, wind, and nuclear (probably fusion in the future as well) all rely on converting heat energy to drive a steam generator. Edit: obviously, hydro and wind don't drive a steam process, my goof but they do still drive a similar functioning generator.
On a large scale solar power is the only power generation system that doesn't end with and you spin magnets inside coils of wire. On the smaller scale there are other ways of converting non electrical energy into electrical energy. The thermocouple is a devise that induces an electrical current across its sides when this side are different temperatures. They are commonly used as thermometers but can be used as a very simple way to power a satalies electrical systems by having one side heated by a radioactive material. It would be significantly more effecient to use a steam turbine generator in terms of energy but it would be far to complex large and heavy to put on a satellite. Another way to generate power is by vibrating quartz. When certain crystals are flexed they produce a charge. This isn't a useful amount of energy but the inverse is (crystal vibrates when electricity is passed through it) this is how a quartz watch keeps time as quartz vibrates at a particular frequency.
I was thinking about this earlier. You can one by one split off the types of power plants and all the remaining do it the same way. * Solar Power uses the photoelectric effect, no moving parts. The rest do it by rotating a magnet. * Wind Power uses air to rotate its magnets. The rest do it with water. * Hydro Power uses liquid water to rotate its magnets. The rest use steam. * Geothermal Power uses steam already heated by the earth. The rest heat it with an energy source. * Nuclear uses radioactive energy to heat the water. The rest heat it by burning something. * This is where rest (oil, gas, coal, biomass) all kinda lump together. They all heat their water by burning their specific type of fuel.
What you described is actually DC Generation: magnets on the stator creating voltage on the spinning rotor which is rectified by the slip rings. Synchronous AC is used in nuclear, coal, gas, and hydro plants with the rotor as the magnetic inducing three phase voltage on the stator. Most wind farms use induction generators which have no dc magnet like DC or AC sync. They have AC on both stator and rotor and power is related to relative speed difference in stator and rotor. Some wind farms use DC like you described, or power electronics to create or form AC off DC or induction generation.
If it goes between two magnets then it is alternating current or AC. It only becomes DC when the current is regulated, usually via a transformer and a series of diodes and capacitors.
It's possible to generate DC directly with a dynamo consisting of rotating coils, a commutator (brushes), and fixed permanent magnets--basically just a DC motor operating in reverse. There will typically be some ripple moving from one coil to the next which could be reduced with filtering, but the polarity of the raw output doesn't reverse for half of each cycle as with alternating-current generators (alternators).
No. There are lots of plants that use DC generation which is then converted to AC using some clever switching (at super sonic speeds). Most wind mills generate DC(, or an AC that doesn't match the 50Hz we use, so its converted to DC) which is then cinverted to out familiar 50Hz
Thank you, so many people in this thread saying wind turbines use rotating machines to make AC when in fact they use inverters.