Perovskite solar cells.
Of all the threads I've seen on this forum, this one seems most naturally to involve the climate. I've mentioned a concern involving wind power myself. I'd like to mention something that came to my attention years ago. A dot that people can check for themselves.
During WWII a group of planes was forced to land on the ice cap. The planes were abandoned. Forty years later it was decided to dig one out, which was successful. It was necessary to dig through 200 feet of ice. That's 5 feet of ice build up per year. The bottom line for me is: "If you think the Greenland ice cap is melting, prove it." Using satellites it should be easy to monitor the altitude of every square foot of the ice cap to some reference point on the Earth.
Daniel_G - Of course your analysis is correct and as Alan Smith has come down on us (quite rightly so) we won't dare mentioning GW again!
Green hydrogen could be a vital tool to limit greenhouse gas emissions from hard-to-decarbonize sectors like steelmaking, shipping and chemicals manufacturing.
But trying to use it as a substitute for natural gas to heat buildings, or even to fuel power plants, could be a pipe dream that wastes precious time and money that would be better directed to more realistic and cost-effective options to reduce carbon.
Green hydrogen is a poor use of expensive electricity. It means taking a high grade energy carrier (electricity) which has close to 100% work potential and then using costly capital equipment and losing one half to one third of the initial energy to convert it into a low grade chemical fuel, which is difficult to store and has 50% work potential at best. The only way it makes sense is if we need hydrogen as a chemical input (I.e ore reduction, cracking reactions or ammonia production), have no cheaper source of hydrogen and we can essentially use hydrogen as quickly as it is being produced, without the problem of storage.
The most sensible first application for green hydrogen would be production of ammonia for ammonium nitrate fertiliser production. The hydrogen doesn't need long-term storage or shipping long distances to serve this need, it can be used at its source and mostly as it is produced. Short term storage could be achieved using gasometer type tanks, at pressure only slightly above atmospheric. This largely avoids leakage issues.
It will be tough for green hydrogen to compete with natural gas as a hydrogen feedstock on a cost basis where natural gas is available. In the US, the spot price for NG has averaged $5 per 1000 cu feet for the past 20 years. That works out at $0.005/MJ, or $0.018/kWh. Now consider that the cost of the green hydrogen will be the cost of electricity (including inefficiencies) and the marginal capital cost of the electrolysis stack and storage solution. Operating and maintenance costs add even more. The marginal capital costs will increase as capacity factor declines. The idea of using hydrogen production to absorb intermittent electricity is a bad one. It results in poor utilisation of an expensive asset and more expensive hydrogen.
Taking all these things together, green hydrogen will cost multiple times what natural gas derived hydrogen will cost where it is available. But if natural gas is not available, then using green hydrogen to make ammonium nitrate beats going hungry. All of these things are going to add to the cost of food. And for people already living on low incomes, the only way they can deal with this cost is by eating less. That is a solution that can only be taken so far before life itself is in jeopardy. For electrolysis derived hydrogen to be as cheap as possible, we need to run it at high capacity factor, very close to its point of generation and exploit high scale economies. In the future, we will need to build GW scale electrolysis plants close to nuclear power plants that can generate electricity cheaply and 24/7. Those electrolysis units will supply neighbouring steel, concrete and ammonia plants. There will be as little storage as possible.
Even exploiting all of these advantages, I cannot see synthetic hydrogen being economically competitive so long as natural gas and coal can be produced for the cost of digging them out of the ground. I think it more probable that electricity from nuclear reactors, wind farms and solar panels, will displace coal and NG as electricity fuels. These fuels can then be deployed where we need industrial high heat and chemical reagents.
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Russia’s invasion of Ukraine exposed just how susceptible energy markets are to disruption from global conflict. But unlike in past wars, clean energy technologies can now offer protection from volatility in oil and gas supplies.
Wind and solar power backed by battery storage can displace electricity produced with coal, gas and oil. Electric vehicle adoption reduces gasoline consumption. Electric heat pumps could replace gas-burning furnaces. None of that is new information, but clean electrification takes on heightened urgency as fossil fuel sales continue to fund the Russian war effort and Europe scrambles for alternatives.
The link below provides a brief description of the Waldpolenz solar park. It is a fairly typical utility scale PV project in Germany.
It's capacity is 52MWe and it produces some 52GWh(e) each year, on average. That is a capacity factor of 11.4%. It covers an area of 220Ha, which is 2,200,000m2. That makes its average area power density 6.84W/m2. Of course, sometimes it will produce more than that. In the winter, a lot less and at night, none at all. But let's work with the average.
To produce an average of 1000MWe of power, about the same as one Westinghouse AP-1000 reactor and about enough for a city of 1 million people, a scaled up solar farm with the same specifications as Waldpolenz, would need to cover 146km2 of land. That's as big as some major cities in Europe. Copenhagen for example has an urban area of 180km2 and is home to some 800,000 people! This tells us that a solar farm big enough to power a city, needs to be about the same size as the whole city.
Previously I referenced the volume of a VVER-1000 nuclear steam supply system. It would comfortably fit into a single 3 storey building. The containment dome, steam turbines, cooling towers, etc, are a lot larger. But still, we are looking at a shopping centre sized power plant, not a city sized power plant. The enormous size of solar power plants is why they take so much energy and materials to build. This is a direct consequence of low power density. For a wind farm, the material volumes are less dramatic, though still an order of magnitude greater than a light water reactor of equivalent annual electricity production. Still, the maximum power density of wind farms in Northern Europe is about 2-3W/m2, depending upon local capacity factor. To power entire countries, RE systems need to be country sized. And they need country sized quantities of concrete and refined metals and all of the fossil fuel powered mining and ore reduction and manufacturing and transport needed to make them and transport them to where they need to be. This is the inescapable drawback of low power density. It is why calling these things 'Green' is really a bad joke.
The worst of it is that these country sized pieces of infrastructure will not even replace FF power stations. These stations still need to be built, maintained and manned and run. And they have to sit there doing nothing, waiting for mother nature to switch off the sun or wind. The most the RE plant can do is reduce the fuel bill in these fossil power plants. And the materials cost associated with that limited achievement is vast. It is why there are serious concerns that PV may not break even in energy payback terms in Northern European countries.
Nevada has a bit more sun than Coventry.
It's been three years to meet the promise of Musk's Green Gigafactory in Nevada. I wonder how and how far along they are.
Roger Andrews explains the situation and what it would take in his article.
"Powering the Tesla Gigafactory" December 12, 2018 by Roger Andrews
Quote
NOTE
MUSK TWEET
August 25, 2018: Tesla’s Gigafactory will be 100% renewable powered (by Tesla Solar) by end of next year
Reference
"Powering the Tesla Gigafactory"
@Dr. Richard
The planes as I recall had to land because of weather. Nothing mysterious. Only one was removed. Probably in a museum.🤠
It's capacity is 52MWe and it produces some 52GWh(e) each year, on average. That is a capacity factor of 11.4%. It covers an area of 220Ha, which is 2,200,000m2. That makes its average area power density 6.84W/m2.
I think it is a bit closer to 10 W/m2. The average solar park produces 351 MWh per year per acre (8760 hours, 4047 m^2). (https://diysolarshack.com/how-…solar-panels-make-income/) That works out to be around 10 W/m^2, year round. Output during the day is 66 kW acre according to one source, which is 16 W/m^2. The actual panel produces 150 to 200 W per square meter at peak sunlight, but apparently much of the solar park is not covered with a panel.
In the U.S. south, the power is generated during peak demand hours, when it sells at the highest price.
To produce an average of 1000MWe of power, about the same as one Westinghouse AP-1000 reactor and about enough for a city of 1 million people, a scaled up solar farm with the same specifications as Waldpolenz, would need to cover 146km2 of land. That's as big as some major cities in Europe.
However, the average solar panel installed in the U.S. lately takes up zero hectares. It is mounted on the roof of a house or building. There is enough roof space to generate a large fraction of the total energy needed. I don't know about Europe, but major cities in the U.S., such as Atlanta, could generate most the electricity they consume right there, with no space taken up and a small distribution network. The same is true of Hiroshima and other southern Japanese cities and towns. In Hawaii, solar panels on houses are putting the power companies out of business.
You might think that 10 W/m^2 is not enough to power a house, but it is close because houses don't take much electricity at night. Of course you need a battery if you only have solar power, but no one is suggesting we should only have solar power. That would be uneconomical. Although it would be nowhere near as uneconomical as having only nuclear power!
Previously I referenced the volume of a VVER-1000 nuclear steam supply system. It would comfortably fit into a single 3 storey building. The containment dome, steam turbines, cooling towers, etc, are a lot larger. But still, we are looking at a shopping centre sized power plant, not a city sized power plant.
A noted by the American Nuclear Society, a nuclear plant takes up around 50 acres plus 1 square mile of buffer space. (https://www.ans.org/news/artic…wind-nuclear-infographic/) That's 640 acres. A solar park of that size generates 224,640 MWh/year or 25.6 MW average. Much less than a nuclear plant! But, as I said, most solar installations take up no space. Power company ones in the Southwest are located in arid places or deserts where there is nothing.
As noted, wind power takes up far less space than nuclear or solar power. However, solar is cheaper than wind in the U.S. because we have lots of space, which is either cheap or it costs nothing (on roofs, parking lots and so on). In agriculture, in some U.S. locations, putting solar panels over a field can enhance the value of the field. Some expensive crops grow better in shade, increasing yield and reducing water consumption. (https://www.wired.com/story/gr…now-theres-a-bright-idea/) In a hot climate such as Atlanta or the southwest, putting solar panels in parking lot solar canopies improves the parking lot. People are more likely to want to park there. Plus, it generates a revenue stream.
A nuclear, coal or natural gas plant never improves the value of agricultural land or a parking lot. You can never put one on a roof.
When calculating the land taken up by coal or natural gas, you have to include space taken by railroad tracks and pipelines.
The actual panel produces 150 to 200 W per square meter at peak sunlight, but apparently much of the solar park is not covered with a panel.
Yup. See:
Quote:
For instance, a 5 MW (megawatt, where 1 MW = 1,000 kW) solar farm would require a minimum of 100 x 5,000 = 500,000 sq. ft.
Given the equivalence of 1 acre = 43, 560 sq. ft., that works out to be about 11 ½ acres needed for a 5 MW solar park.
Note that’s just for the panels. Figure in an additional 8-10 acres more to house other solar system hardware plus the space needed between rows to avoid shading (and consequent power loss) as well as space for periodic array maintenance.
| Technology | Average direct land use (acres/MWac) | Average total land use (acres/MWac) |
|---|---|---|
| Small PV (>1MW, <20MW) | 5.9 | 8.3 |
| Fixed | 5.5 | 7.6 |
| Single-Axis | 6.3 | 8.7 |
| Dual-axis, flat panel | 9.4 | 13 |
| Dual-axis, CPV | 6.9 | 9.1 |
| Large PV (>20MW) | 7.2 | 7.9 |
| Fixed | 5.8 | 7.5 |
| Single-Axis | 9.0 | 8.3 |
| Dual-Axis CPV | 6.1 | 8.1 |
MWAC means megawatt alternating current. 13 acres average total land use is 52,609 m^2, which comes to 19 W/m^2. I assume that is peak power. 7.6 acres comes to 33 W/m^2.
But still, we are looking at a shopping centre sized power plant, not a city sized power plant.
No, we are looking at 64 shopping centers. In the U.S., anyway. The average shopping center in the U.S. takes up 10 acres according the the Chicago Association of Realters. A nuclear plant needs a 1 square mile buffer according to the American Nuclear Society. That's 640 acres.
As I said, the average new solar installation in the U.S. takes up zero acres, or many acres in the middle of nowhere in the southwest. Rooftop installations have recently outpaced solar farms. The situation may be different in Europe.
The enormous size of solar power plants is why they take so much energy and materials to build.
They take far less materials. You can put them on your roof. Putting the equivalent weight of 10 kW worth of nuclear plant on your roof would crush the house flat. Think of the containment structure and the cooling towers! The only power source that takes more material than a nuclear plant is a hydroelectric dam.
Hydroelectric dams last much longer than nuclear plants. At least 100 years. So, the mass of material per year may be lower. The turbines generators in the dam are replaced periodically, but they can be melted down and recycled. That is also true of wind turbine generators. Most of the material is in the tower, which should last 100 years, a lot longer than any nuclear plant. So material consumption measured per year, or per watt-hour of electricity over the life of the system is much lower than a nuke. A wind turbine generator can be completely recycled. The blades cannot be recycled at present, but that may change. I doubt that any part of a nuclear reactor is recycled. It is radioactive. Recycling solar cells is improving. In other words, over the long term (hundreds of years), with recycling, the total mass of materials needed to generate electricity with wind or solar is much lower than fission reactors.
The energy cost is about the same for all three. It is measured in energy payback time. That is, how long does it take for the nuke, wind turbine, or solar cell to produce as much energy as it took to manufacture it? It ranges from 3 to 6 months for all three. Some solar installations take a lot longer -- up to 2 years. I expect they are put in places where other power sources are not available, such as remote locations.
Solar, wind, or burning your furniture is 16 times cheaper than the nuclear plant being constructed in Georgia, but that is because of engineering mistakes and mistakes in construction, not because of the materials. The materials, and the complexity and danger of the equipment alone would make nukes about 10 times more expensive than wind or solar per watt of capacity, taking into account capacity factors (EIA). More than that over the life of the plant because uranium fuel costs money, and decommissioning costs tons of money, whereas solar does not require any fuel and it is cheap to decommission, and will eventually be cheap to recycle.
We should not lose sight of the fact that the metric which makes the biggest difference in power generation is not the space taken up, or the mass of material, or the energy payback time. It is money. M-o-n-e-y. Money is why 46% of U.S. new capacity this year will be solar, 17% wind, and nuclear will never be even 1% after the Georgia Plant Vogtle fiasco is finished. If it ever is. (https://www.eia.gov/todayinenergy/detail.php?id=50818)
Electric power executives understand the economics of power generation. They understand what it costs. Apart from the idiots running Georgia Power, none of them has tried to build a nuclear plant since 1996, and none will ever make that mistake again. It is economic insanity. Discussions about how much land it takes are irrelevant. Building a nuclear plant bankrupted Westinghouse, the last U.S./Japanese company in that business. They owe Georgia Power $3 billion. There is no one else capable of doing it, and no one would be that stupid.
The situation may be different in Europe, where there is less land and less wind and solar resources. The U.S. has enough wind and solar power to supply the entire world with energy, if we could send it. (Europe has about 4 times more electric power resources than it consumes, in North Sea wind.)
Jed Rothwell, you are trying to wordsmith your way around the laws of physics. All discussions with renewable energy enthusiasts seem to end this way. They always tie themselves in knots trying to argue the unarguable. This is why we are in the energy mess that we are in. People end up advocating courses of action based on ideology rather than arithmetic.
Rooftop solar is the most expensive commercially available electricity source. Yes, with a lot of human labour, you can do away with the steel support frame needed to hold it at a 30 degree angle against the weather. But you must also contend with the fact that the majority of roof tops are not going to be optimally orientated or at the optimum angle.
Display MoreThey take far less materials. You can put them on your roof. Putting the equivalent weight of 10 kW worth of nuclear plant on your roof would crush the house flat. Think of the containment structure and the cooling towers! The only power source that takes more material than a nuclear plant is a hydroelectric dam.
Hydroelectric dams last much longer than nuclear plants. At least 100 years. So, the mass of material per year may be lower. The turbines generators in the dam are replaced periodically, but they can be melted down and recycled. That is also true of wind turbine generators. Most of the material is in the tower, which should last 100 years, a lot longer than any nuclear plant. So material consumption measured per year, or per watt-hour of electricity over the life of the system is much lower than a nuke. A wind turbine generator can be completely recycled. The blades cannot be recycled at present, but that may change. I doubt that any part of a nuclear reactor is recycled. It is radioactive. Recycling solar cells is improving. In other words, over the long term (hundreds of years), with recycling, the total mass of materials needed to generate electricity with wind or solar is much lower than fission reactors.
The energy cost is about the same for all three. It is measured in energy payback time. That is, how long does it take for the nuke, wind turbine, or solar cell to produce as much energy as it took to manufacture it? It ranges from 3 to 6 months for all three. Some solar installations take a lot longer -- up to 2 years. I expect they are put in places where other power sources are not available, such as remote locations.
Solar, wind, or burning your furniture is 16 times cheaper than the nuclear plant being constructed in Georgia, but that is because of engineering mistakes and mistakes in construction, not because of the materials. The materials, and the complexity and danger of the equipment alone would make nukes about 10 times more expensive than wind or solar per watt of capacity, taking into account capacity factors (EIA). More than that over the life of the plant because uranium fuel costs money, and decommissioning costs tons of money, whereas solar does not require any fuel and it is cheap to decommission, and will eventually be cheap to recycle.
Hydroelectric dams are indeed long lived pieces of equipment. Compared to other renewable energy sources, they have much higher power density, especially the moving parts and are controllable. This is why they were the first large scale electricity generating plants to be built. Ideally, we would like to have more of them. But large rivers are a limited resource. I do not have any detailed figures on hydroelectric materials consumption per TWh.
The situation could hardly be more different for other more intermittent renewable. Wind power declined in Europe as soon as the steam engine became available. However, steam, coal and diesel power, are precisely what enabled large hydroelectric dams to be built. Power density is everything. It is why we are bothering to pursue LENR when there is already abundant sunlight available. The promise of nuclear power, with all it's power density, without hard radiation.
Solar cells are not at present recyclable. The steel, aluminium and glass may be. The copper and silver no doubt will be to a degree at least. Only a tiny fraction of a nuclear power plant steel and concrete is radioactive. The primary circuit, the shielding concrete around the core and some surface contamination in the fuel ponds. The remainder is recyclable.
Compared to other renewable energy sources, they have much higher power density, especially the moving parts and are controllable.
Not when you measure the ground area of a wind turbine tower. They range from 1 to 2 MW actual per 20 m^2. Much better than any nuke or hydroelectric dam. The area swept by the blades is gigantic, of course. The area taken up by the entire wind farm is gigantic, but it can be used for farmland.
The situation could hardly be more different for other more intermittent renewable.
It isn't really intermittent in places like Oklahoma, or offshore. It blows just about every day. Over a large area such as the 220,000 acre wind farm, it always blows somewhere. It can be predicted a week ahead of time. It is more predictable and reliable than a nuke, because it does not suddenly crash in a SCRAM event. (One turbine might go out, but you don't lose the whole wind farm suddenly.)
Solar cells are not at present recyclable.
But they soon will be.
Jed Rothwell, you are trying to wordsmith your way around the laws of physics. All discussions with renewable energy enthusiasts seem to end this way. They always tie themselves in knots trying to argue the unarguable.
Not me. You are saying that the people in charge of power companies tie themselves into knots. Nearly all new construction is now wind and solar. You are saying they are throwing away billions of dollars because they do not understand the laws of physics.
I expect they know more than you do.
Rooftop solar is the most expensive commercially available electricity source.
Not in the U.S. It is 6 cents per kilowatt hour, compared to the average of 13 cents. Electricity is far more expensive in some states, especially Hawaii, where it is 32 cents/kWh. The sun shines nearly every day there, so many people are installing solar, so the power companies are facing bankruptcy.
Not in the U.S. It is 6 cents per kilowatt hour, compared to the average of 13 cents.
It is roughly 8 cents per kilowatt hour in Georgia, compared to the average cost of 12 cents/kWh from the power company. Sources:
https://modernize.com/solar/panel-cost-calculator
Solar panel installation costs a national average of $18,500 for a 6kW solar panel system for a 1,500 square ft. home. The price per watt for solar panels can range from $2.50 to $3.50, and largely depends on the home’s geographical area. Residential solar panels are usually sized at 3kW to 8kW and can cost anywhere from $9,255 and $28,000 in total installation costs. See average solar panel system costs by size (before tax credits or discounts).
Another estimate:
https://www.consumeraffairs.com/solar-energy/how-much-do-solar-panels-cost.html
Georgia: 6-kW system, $15,840, before tax credits.
This table says that's $2.33/W including installation, but I get $2.64/W. The two estimates are from different sources:
$15,840 "Before tax credits, according to EnergySage and Solar Reviews"
$2.33 "According to Solar Reviews"
Various sites say that production from a solar panel over a year is ~15% of nameplate (peak rated) production. One site says a 370 W nameplate panel produces between 1400 Wh/day and 1900 Wh/day. That's 16% to 21% of nameplate. This is for the panel itself, not the whole installation, which may have surface area without panels. That's roughly equivalent to 5 hours per day peak production.
Anyway, for a 6-kW installation, that would be 7884 kWh/year, or 0.9 kW average for the entire year, day and night.
Most sites say that panels last 25 to 30 years. Over 25 years, total output from a 6-kW system is ~197,100 kWh.
$15,840 / 197,100 kWh = $0.08/kWh
You can see that if the cost drops to something like $1/W ($6,000 for a 6-kW system), the cost would be 3 cents/kWh. People everywhere will want rooftop installations if that happens.
In 2017, solar power cost the power companies 6 cents/kWh with utility scale installations. That includes the cost of construction, panels, and so on. That is according to the DoE. They are hoping the price falls to 3 cents by 2030. Source: https://www.energy.gov/eere/solar/sunshot-2030
One source says that utility scale solar electricity costs 2.4 cents/kWh wholesale, before T&D costs.
See:
