Solar Company Says Its Tech Can Power 90 Percent of Grid and Cars
Solar-power-plant company Ausra has released a paper claiming that solar-thermal electric technology can provide 90 percent of U.S. grid electricity, with enough left over to power a fleet of plug-in electric vehicles. The company estimates that such a changeover would eliminate 40 percent of the country's greenhouse gas emissions with a land footprint of 9,600 square miles, about the size of Vermont
My calculator indicates...an area of 9,531 square miles, which is equivalent to a square of just under 100 miles by 100 miles (which would be 10,000 square miles). That's a large area, to be sure. But the possibility is there. A lot of "land" is available right now of rooftops.
A couple of caveats. First, this calculation does not make a provision for a mass migration to electric transport. That would clearly require (a lot) more power.
However, note that my calculation - based on an actual solar thermal plant - did not include anything extra for electric transportation.
I believe I've seen stats comparing land usage of solar versus land usage for coal. Coal usage of course is not just the land where the plant is, but land where the coal is stored before transit, and the land that is mutilated upon mining as well. Large amounts of train cargo capacity is taken up by coal transports as well. Water usage from coal and nuclear is also an issue.
As the main article points out, there is a lot of available "land" in the form of rooftops and also parking lots. A parking lot with solar panels above vehicles would provide shading while charging cars or dumping power into the grid. A win-win by many measurements. In hot environments, having solar panels on the roof to allow air space between the panels and the roof allows the roof to be shaded, and less cooling requirements for the building.
Interesting comment about the reduced cooling requirements. In computing solar output, I guess solar companies should start talking about imputed output as well, from the cooling effect. On the other hand, what would the effect on heating be on sunny days in the winter.
This is worth considering, and has a number of useful combinations that can make Lemonade out of this in either seasonal extreme.
Here in a Colder climate (Coastal Maine), the shade on my roof ought to have barely a marginal effect on my 'Well-insulated' Attic, while the sun originally hitting that rooftop better NOT be considered some piece of my Passive Solar Heating Scheme, since surely some 95% or more of the heat of Sun hitting shingles is reflected or blown away, and never gets inside. In addition, the colder air keeps the PV functioning at a higher efficiency than a "hot" panel in warmer climes.
In Hot Climates, (perhaps all), it could be useful to Water Cool the panels, and let that be a preheating stage for your domestic Hot Water or Other Heating Needs. If PV gets to the point of being a Status symbol, I've even advocated putting 'Dummy' Panels up on one's Phoenix rooftops (my father-in-law, anyway), and get the benefit of the shade, plus the Cache'!
I'm eager to cover my rooftop with PV and Heating Panels of one sort or another, to keep these shingles young and fresh, and keep my attic from 'sweltering up' every summer. The Hot air panels that oftentimes have to get covered in the summertime, I have considered keeping active and ducting them to the Dryer, switching off the heater coils.. and to a Food Dehydration center in the basement. (I know, I know, clotheslines, yada, yada.. but we have very little, not too sunny- yard space, and the passage from Washer to yard is a challenge)
Antidoomer.. you got good discussion started today. Good work!
New solar-panel technology coming later this year will combine a solar PV panel with thin-plate back panel with fluid channels that absorbs most of the thermal energy of the PV cells (which isn't converted to electricity). With a single installation, there's kilowatts of electrical power to net-zero the electric bill, and all the hot water the family needs. This has the additional advantage of cooling the PV silicon so it's about 10% more efficient - that is, a typical Sharp, Sanyo, or Evergreen panel goes from 15% to about 16.5% efficient.
If you're interested in this, send me private email or look me up at the American Solar Energy conference & trade show in San Diego 5-8 May.
Dick Lawrence
ASPO-USA
dlawrence2 (at) gmail (dot) com
Solar power is all the rage2 in the energy markets because of the thin film revolution, which promises low-cost mass production of photovoltaic (PV) cells (Technology Review, July 27, 2007). Leading the way is First Solar, which uses cadmium-telluride thin-film PVs in its solar panels. Scientific American's solar "grand plan" cites cadmium telluride as the cheapest option today.
To provide electricity at six cents per kWh by 2020, cadmium telluride modules would have to convert electricity with 14 percent efficiency, and systems would have to be installed at $1.20 per watt of capacity. Current modules have 10 percent efficiency and an installed system cost of about $4 per watt. Progress is clearly needed, but the technology is advancing quickly; commercial efficiencies have risen from 9 to 10 percent in the past 12 months...
First Solar has its detractors, who "assert that the company could be hurt by limited supplies of raw materials in the future and increased competition." It turns out that tellurium is one of the nine rarest elements on Earth. Here's the smoking gun from altenergystocks.com—
In 2006, First Solar's 60 megawatts of production consumed 4% of the world's annual supply of [tellurium]. In 2008, analysts expect revenues of approximately 4x the 2006 number, meaning they will need approximately 16% of new annual Tellurium supplies.
60 megawatts is nothing, a drop in the bucket. So much for cadmium-telluride thin film. But what of the many other alternatives?
For four years now, purified silicon has been in short supply. See the Wall Street Journal's The Silicon Shake-Up (subscriber only, September 21, 2007). Polysilicon prices soared from $25/kilogram in 2004 to around $200/kilogram in 2006, and PV production growth has come to a virtual halt. Sharp, the largest solar cell manufacturer in the world, "produced panels that could generate 434 megawatts of electricity [in 2006], or the equivalent of a single gas-fired power plant, about the same amount it made in 2005." The shortage has spurred the thin film craze because investors are leery of the polysilicon supply & demand imbalance, even though thin film PVs are only 7-10% efficient in converting sunlight, as opposed to about 15% for commercial silicon PVs.
In the case of depletion, as with cadmium telluride, the optimist might also respond that there are other alternatives, such as the copper-indium-(gallium)-diselenide (CIS or CIGS) thin film technology being pursued by Siemens, Nanosolar or Global Solar Energy. The risk is that the current bullish commodities market may become a permanent feature of the economic landscape. Take the indium used in thin films. Resource Investor reports that—
The Earth is estimated to contain about 0.1 ppm [parts per million] of indium which means it is about as abundant as silver. However, bullish supply-demand fundamentals have propelled the price from US$70/kg in 2001 to over US$1,000/kg today.
Indium is produced mainly from residues generated during zinc ore processing but is also found in iron, lead, and copper ores. In recent years, supply has decreased after a number of Chinese mining concerns stopped extracting indium from their zinc tailings.
At present, about 75% of the indium in the world is used in the manufacture of Liquid Crystal Displays (LCD’s), in computer screens and the new generation of flat screen TVs. The LCD industry is expected to achieve growth rates exceeding 30% over the next three years.
Looks like the solar cell industry will not be efficient for the campaign to...........
Wow, Cherenkov, thanks for not providing something helpful on my question and posting a unrelated answer, thanks! Anywho, here's a article on how indium could be replace by carbon nanotubes.
Antidoomer;
To be fair, what Cherenkov just did, pulling a grand (in this case negative) conclusion from a single article, as if that said it all, is the same tactic that a number of your posts get so attacked for. I think there's an implication in them that says 'So there. Here's an alleged solution. What energy problem?' Even if that's not really your intention, it is the subtext that I sense from them again and again, and it doesn't usually offer much beyond a sort of Adamant Triumphalism, as opposed to simply hopefulness.
Anti: All this talk about the GIANT solar power industry. The solar power industry is a shrimp predicted to be a giant. This shrimp has been predicted to be a giant for quite a while now. Cherenkov was making a good point-a shrimp growing quickly does not a giant make.
Cherenkov is happy any time he can howl about Cars being evil.
I generally find Alan Drake's way of putting it much more convincing and productive, which is to say that Electric rail and Bikes make more sense than EVs. Adding a lot of exclamation marks and bold-type makes cherenkov's arguments weaker, not stronger. Misspent Energy, if you will.
First Solar has its detractors, who "assert that the company could be hurt by limited supplies of raw materials in the future and increased competition."
There may not be enough tellurium to cover all our rooftops with solar panels made from them but I'm sure there is enough for First Solar while we attempt it.
Sounds like a great idea, but likely isn't. Given that one needs 2 (that's two) layers of glass for minimal thermal insulation, the PV output will be reduced about 8% for each extra layer. Also, is the PV layer going to exhibit different spectral characteristics in the infrared (reflecting) vs. the visible (absorbing)? Otherwise, the infrared emissions will reduce the efficiency of the thermal collection side of the efficiency equation.
I saw a posting last week about a system using air cooling, without any insulating cover plates. That one looked like a complete waste of effort to me, since the thermal efficiency would go to zero when the ambient temperature was low. The result, no hot water in winter.
There was a very popular exposition of this idea in Scientific American a few months ago. My question is, supposing the political decision is made to switch over to solar panels, and the appropriate funds would be found in a combination of public (tax-supported according to those authors) and private investment -- and that is some politics! -- what would be the environmental cost of building all those solar panels? Is it really that simple?
No, of course it isn't really that simple. I only did the calculation out of curiousity. I wanted to know if it was remotely feasible. The answer I got was "Yes, it is technically feasible from a land usage POV." You get a much different answer if you try to calculate whether we can run our present transportation system on biofuels. The answer to that is "No."
Photosythesis is 4 to 5 percent efficient.
An ICE-auto is 15% efficient (maybe).
.045 * .15 = .00675
That's right. Less than 1/10 of one percent is translated from the sun to actual motive power. Now... why on earth would we consider depleting the soil and our aquifers, raising all food costs... for 1/10 of one percent?
Where are you kdolliso? There are limits to growth...
Its less than 1% efficient in converting sunlight into sugars, starches or cellulose.
0.007 * .15 = 0.00105 (~ 1/100)
Everyday the world consumes 400 years of stored global sunlight. To become sustainable, we need to reduce our total global consumption by about a factor of 1/150,000.
That's just about the same figure National Geographic used in Aught Five. Technology is more efficent now.
With solar now providing less than one percent of the world's energy, that would take "a massive (but not insurmountable) scale-up," NYU's Hoffert and his colleagues said in an article in Science. At present levels of efficiency, it would take about 10,000 square miles (30,000 square kilometers) of solar panels—an area bigger than Vermont—to satisfy all of the United States' electricity needs. But the land requirement sounds more daunting than it is: Open country wouldn't have to be covered. All those panels could fit on less than a quarter of the roof and pavement space in cities and suburbs.
Made from the Earth's most abundant substance -- sand -- polysilicon is tricky to manufacture. It requires huge amounts of energy, and even a small misstep in the production can introduce impurities and ruin an entire batch. The other main challenge is dealing with the waste. For each ton of polysilicon produced, the process generates at least four tons of silicon tetrachloride liquid waste.
I still wonder if mass production of silicon cells will have un-anticipated consequences. And solar-thermal will create some massive distortions in water supply. Not that it can't be done -- but there seem to be some major exclusions from the theoretical calculations.
They are already producing photovoltaic cells at about a tenth of the cost of traditional silicon photovoltaics, making the cost equivalent to the cost of coal produced electricity.
Nanosolar has been mentioned somewhat regularly here.
I think they are sitting in the 'Wait and See' box right now, to see if they can live up to their claims. Even if they are producing and delivering product now, my particular concern is that a much lighter, thinner, cheaper material might end up having a consequently abbreviated lifespan, thereby unhinging the presumed price or energy-input advantages.
As MFR energy becomes more dear, I hope to see a renewed emphasis on building products that will last, and get away from our Disposable/Replaceable Product model.
These 'Expensive' panels that we know can last decades might turn out to be worth the investment. I am glad that new developments are happening, just the same.
The most important tidbit of information in this story is,
...more than 20 Chinese companies are starting polysilicon manufacturing plants. The combined capacity of these new factories is estimated at 80,000 to 100,000 tons -- more than double the 40,000 tons produced in the entire world today.
The cost of modules should drop precipitously with this amount of poly hitting the market.
Lets be clear here. What is being talked about is solar thermal. In fact, for those wondering go look at that old popular science magazine. Solar thermal won't be on anyones roof or pavement space in urban areas. It is an array of mirrors that focuses the suns heat onto, usually some form of salt. The salt is super heated until it melts. The heat is transferred to make steam that drives turbines to make electricity.
This is not your mothers solar panel that turns the sun right into electricity on the surface of the panel. These are large scale set ups that would be constructed in desert areas, and maintained by governments or utilities. Their efficiency is amazing, and they can run 24/7 as the molten salt from the day time can continue to heat and drive steam turbines through the night.
The view of them is amazing. There is a sort of carona that forms at the top around the center. It looks like floating fire. Temperatures generated are amazingly hot, so do not try this at home.
Power towers are only one of a bunch of solar-thermal technologies that are in the marketplace. All of them have the advantage that they produce electricity more cheaply than photovoltaic panels and are easier to manufacture. Some of them, like Stirling Energy's tracking dishes are compatible with other uses. It will be interesting over the next few years to see which solar thermal approach proves to be the most common.
"—to satisfy all of the United States' electricity needs."
That phrase also has to be kept well-salted in these discussions, since these hypothetical numbers don't mean that the great majority of Solar Electricity Advocates are really proposing to satisfy ALL of our current current just with PV or CSP, and so that square milage is already a great deal smaller, as Solar shares the load with Hydro, CoGen, Wind, Tidal, some say Nuclear, whatever.
On top of that, or I should say 'Off the top of that' also comes all the countless reductions we can implement, whether it's efficiency, removing silly redundancies and luxuries, etc. How much can we cut out of this fatty energy demand of today? It's 25degrees out, but my fridge and a separate freezer are both still running, in a house that I PAY to heat around those chilled boxes. How many homes in the summer are being 'Heated' by that same fridge's compressor, as they spend money to cool that house? There's so much we can do that wouldn't even be a major change.. and then, there are the major changes..
It was in the upper 30s here last night and at least four or five people in my building were running their air conditioners. It got warm enough during the day that those people turned on the AC and it probably didn't occur to them at all that after the sun went down, they could have cracked a window.
These numbers are silly. Look at it this way: each household's electrical needs can be supplied by about 12 120W solar panels. The cost of that would be about $12-$25K, depending on whether substantial storage (batteries etc) would also be necessary. Compared to the cost of a house, that is not very much. There would be commercial needs too, but there is also lots of commercial roof space available. Add a bit of wind and existing nuclear/hydro capability, and you have a perfectly functional electrical system.
This idea that electricity needs to be some massive project hundreds of miles from people is based on expectations for existing coal-fired plants, where there are great economies of scale.
from Backwoodssolar.com:
#5 LARGE HOME / SMALL BUSINESS
$18,000 to $33,000
PRODUCES ABOUT 10 USABLE KILOWATT-HOURS ON A SUNNY DAY
When Backwoods was off-grid, we ran 4 computers 10 hours a day, 3 answering machines, fax, 3 wireless phones, office and stockroom lights, work bench and shop tools. We also had all the usual residential power described in example #4, including several solar electric design refrigerators. A true Sine Wave inverter runs washing machines and power tools. Stereos, ceiling fans and appliances don’t hum. Includes automatic generator start as batteries or loads require. Battery voltage of 24 volt or 48 volt is recommended. 24 volt battery bank requires 6-volt batteries set up in multiples of 4, while 48 volt requires multiples of 8. This is simplified by factory assembled equipment.
SOLAR 2080 WATTS: (sixteen KC130 watt modules on two mounts of eight)
BATTERIES: (12 - 16 Trojan L-16HC or larger Surrettes, and cables)
OUTBACK Flexware 500 POWER SYSTEM: with 1 or 2 inverters
Recommended Generator: Kohler 10ERG
I noted that once as well. I think the overall area required is similar, though. I had done a calculation of solar PV once before and came up with something like a 50 mile by 50 mile area, but there was nothing in there for infrastructure. The solar thermal plant has a lot of infrastructure associated with it.
A couple of caveats. First, this calculation does not make a provision for a mass migration to electric transport. That would clearly require (a lot) more power.
We can replace all heavy truck & railroad oil use with 2.x% of current US electricity use via electrified rail.
0.19% of US electricity is used to power the NYC subways, the Northeast Corridor, Long Island RR, subways in DC, Chicago, Philly, Boston, LA, Atlanta, Miami, and light rail in a couple of dozen cities.
Increase that 21 fold (twenty-one NYC subways, twenty-one LIRRs, twenty-one DC Metros, etc.) to 4% of current US electricity demand and such a massive build-out would truly transform the United States !
The lost growth and reduced demand of a severe recession could supply that much (6.x%) "surplus" electricity.
http://blog.wired.com/wiredscience/2008/03/solar-company-s.html
Solar Company Says Its Tech Can Power 90 Percent of Grid and Cars
I recently came up with a very similar figure:
Running the U.S. on Solar Power
However, note that my calculation - based on an actual solar thermal plant - did not include anything extra for electric transportation.
I believe I've seen stats comparing land usage of solar versus land usage for coal. Coal usage of course is not just the land where the plant is, but land where the coal is stored before transit, and the land that is mutilated upon mining as well. Large amounts of train cargo capacity is taken up by coal transports as well. Water usage from coal and nuclear is also an issue.
As the main article points out, there is a lot of available "land" in the form of rooftops and also parking lots. A parking lot with solar panels above vehicles would provide shading while charging cars or dumping power into the grid. A win-win by many measurements. In hot environments, having solar panels on the roof to allow air space between the panels and the roof allows the roof to be shaded, and less cooling requirements for the building.
Interesting comment about the reduced cooling requirements. In computing solar output, I guess solar companies should start talking about imputed output as well, from the cooling effect. On the other hand, what would the effect on heating be on sunny days in the winter.
This is worth considering, and has a number of useful combinations that can make Lemonade out of this in either seasonal extreme.
Here in a Colder climate (Coastal Maine), the shade on my roof ought to have barely a marginal effect on my 'Well-insulated' Attic, while the sun originally hitting that rooftop better NOT be considered some piece of my Passive Solar Heating Scheme, since surely some 95% or more of the heat of Sun hitting shingles is reflected or blown away, and never gets inside. In addition, the colder air keeps the PV functioning at a higher efficiency than a "hot" panel in warmer climes.
In Hot Climates, (perhaps all), it could be useful to Water Cool the panels, and let that be a preheating stage for your domestic Hot Water or Other Heating Needs. If PV gets to the point of being a Status symbol, I've even advocated putting 'Dummy' Panels up on one's Phoenix rooftops (my father-in-law, anyway), and get the benefit of the shade, plus the Cache'!
I'm eager to cover my rooftop with PV and Heating Panels of one sort or another, to keep these shingles young and fresh, and keep my attic from 'sweltering up' every summer. The Hot air panels that oftentimes have to get covered in the summertime, I have considered keeping active and ducting them to the Dryer, switching off the heater coils.. and to a Food Dehydration center in the basement. (I know, I know, clotheslines, yada, yada.. but we have very little, not too sunny- yard space, and the passage from Washer to yard is a challenge)
Antidoomer.. you got good discussion started today. Good work!
Bob
New solar-panel technology coming later this year will combine a solar PV panel with thin-plate back panel with fluid channels that absorbs most of the thermal energy of the PV cells (which isn't converted to electricity). With a single installation, there's kilowatts of electrical power to net-zero the electric bill, and all the hot water the family needs. This has the additional advantage of cooling the PV silicon so it's about 10% more efficient - that is, a typical Sharp, Sanyo, or Evergreen panel goes from 15% to about 16.5% efficient.
If you're interested in this, send me private email or look me up at the American Solar Energy conference & trade show in San Diego 5-8 May.
Dick Lawrence
ASPO-USA
dlawrence2 (at) gmail (dot) com
Sounds interesting and exciting Dick. Can you post a link concerning this technology?
http://www.energybulletin.net/40936.html
Looks like the solar cell industry will not be efficient for the campaign to...........
SAVE THE AUTOMOBILE!!!
Wow, Cherenkov, thanks for not providing something helpful on my question and posting a unrelated answer, thanks! Anywho, here's a article on how indium could be replace by carbon nanotubes.
http://www.eetimes.com/showArticle.jhtml?articleID=201201762
Antidoomer;
To be fair, what Cherenkov just did, pulling a grand (in this case negative) conclusion from a single article, as if that said it all, is the same tactic that a number of your posts get so attacked for. I think there's an implication in them that says 'So there. Here's an alleged solution. What energy problem?' Even if that's not really your intention, it is the subtext that I sense from them again and again, and it doesn't usually offer much beyond a sort of Adamant Triumphalism, as opposed to simply hopefulness.
Respectfully,
Bob
Anti: All this talk about the GIANT solar power industry. The solar power industry is a shrimp predicted to be a giant. This shrimp has been predicted to be a giant for quite a while now. Cherenkov was making a good point-a shrimp growing quickly does not a giant make.
Cherenkov is happy any time he can howl about Cars being evil.
I generally find Alan Drake's way of putting it much more convincing and productive, which is to say that Electric rail and Bikes make more sense than EVs. Adding a lot of exclamation marks and bold-type makes cherenkov's arguments weaker, not stronger. Misspent Energy, if you will.
Bob
As far as potential limits to solar cell manufacture, I found this report: Future State of the PV Industry - Trends and Technologies to be instructive.
There may not be enough tellurium to cover all our rooftops with solar panels made from them but I'm sure there is enough for First Solar while we attempt it.
Sounds like a great idea, but likely isn't. Given that one needs 2 (that's two) layers of glass for minimal thermal insulation, the PV output will be reduced about 8% for each extra layer. Also, is the PV layer going to exhibit different spectral characteristics in the infrared (reflecting) vs. the visible (absorbing)? Otherwise, the infrared emissions will reduce the efficiency of the thermal collection side of the efficiency equation.
I saw a posting last week about a system using air cooling, without any insulating cover plates. That one looked like a complete waste of effort to me, since the thermal efficiency would go to zero when the ambient temperature was low. The result, no hot water in winter.
E. Swanson
There was a very popular exposition of this idea in Scientific American a few months ago. My question is, supposing the political decision is made to switch over to solar panels, and the appropriate funds would be found in a combination of public (tax-supported according to those authors) and private investment -- and that is some politics! -- what would be the environmental cost of building all those solar panels? Is it really that simple?
No, of course it isn't really that simple. I only did the calculation out of curiousity. I wanted to know if it was remotely feasible. The answer I got was "Yes, it is technically feasible from a land usage POV." You get a much different answer if you try to calculate whether we can run our present transportation system on biofuels. The answer to that is "No."
That is a great comment -- and the start of a useful political discussion that might actually advance the argument.
Here's the way I look at it.
Photosythesis is 4 to 5 percent efficient.
An ICE-auto is 15% efficient (maybe).
.045 * .15 = .00675
That's right. Less than 1/10 of one percent is translated from the sun to actual motive power. Now... why on earth would we consider depleting the soil and our aquifers, raising all food costs... for 1/10 of one percent?
Where are you kdolliso? There are limits to growth...
Its less than 1% efficient in converting sunlight into sugars, starches or cellulose.
0.007 * .15 = 0.00105 (~ 1/100)
Everyday the world consumes 400 years of stored global sunlight. To become sustainable, we need to reduce our total global consumption by about a factor of 1/150,000.
That's just about the same figure National Geographic used in Aught Five. Technology is more efficent now.
With solar now providing less than one percent of the world's energy, that would take "a massive (but not insurmountable) scale-up," NYU's Hoffert and his colleagues said in an article in Science. At present levels of efficiency, it would take about 10,000 square miles (30,000 square kilometers) of solar panels—an area bigger than Vermont—to satisfy all of the United States' electricity needs. But the land requirement sounds more daunting than it is: Open country wouldn't have to be covered. All those panels could fit on less than a quarter of the roof and pavement space in cities and suburbs.
http://ngm.nationalgeographic.com/ngm/0508/feature1/index.html
Solar Energy Firms Leave Waste Behind in China
I still wonder if mass production of silicon cells will have un-anticipated consequences. And solar-thermal will create some massive distortions in water supply. Not that it can't be done -- but there seem to be some major exclusions from the theoretical calculations.
Have you heard of Nanosolar?
http://www.nanosolar.com/
They are already producing photovoltaic cells at about a tenth of the cost of traditional silicon photovoltaics, making the cost equivalent to the cost of coal produced electricity.
Nanosolar has been mentioned somewhat regularly here.
I think they are sitting in the 'Wait and See' box right now, to see if they can live up to their claims. Even if they are producing and delivering product now, my particular concern is that a much lighter, thinner, cheaper material might end up having a consequently abbreviated lifespan, thereby unhinging the presumed price or energy-input advantages.
As MFR energy becomes more dear, I hope to see a renewed emphasis on building products that will last, and get away from our Disposable/Replaceable Product model.
These 'Expensive' panels that we know can last decades might turn out to be worth the investment. I am glad that new developments are happening, just the same.
Bob Fiske
The most important tidbit of information in this story is,
The cost of modules should drop precipitously with this amount of poly hitting the market.
"The cost of modules should drop.."
Not if demand remains strong.
For what they can do, I still say they're worth buying at today's prices. I tend to doubt tomorrow's costs will be better.
Bob
Lets be clear here. What is being talked about is solar thermal. In fact, for those wondering go look at that old popular science magazine. Solar thermal won't be on anyones roof or pavement space in urban areas. It is an array of mirrors that focuses the suns heat onto, usually some form of salt. The salt is super heated until it melts. The heat is transferred to make steam that drives turbines to make electricity.
This is not your mothers solar panel that turns the sun right into electricity on the surface of the panel. These are large scale set ups that would be constructed in desert areas, and maintained by governments or utilities. Their efficiency is amazing, and they can run 24/7 as the molten salt from the day time can continue to heat and drive steam turbines through the night.
The view of them is amazing. There is a sort of carona that forms at the top around the center. It looks like floating fire. Temperatures generated are amazingly hot, so do not try this at home.
Power towers are only one of a bunch of solar-thermal technologies that are in the marketplace. All of them have the advantage that they produce electricity more cheaply than photovoltaic panels and are easier to manufacture. Some of them, like Stirling Energy's tracking dishes are compatible with other uses. It will be interesting over the next few years to see which solar thermal approach proves to be the most common.
Don't Try this at Home
They all ready are. Look what you can do with an 8ft satelite dish.
Melt aluminum or lead, produce steam.
Take a look at the site
http://www.junkyardsolar.com/page1.html
Point that thing at a Stirling engine, eh?
I wish I could find a Stirling engine the size of a Briggs&Stratton that worked.
Maybe a http://www.greensteamengine.com/
"—to satisfy all of the United States' electricity needs."
That phrase also has to be kept well-salted in these discussions, since these hypothetical numbers don't mean that the great majority of Solar Electricity Advocates are really proposing to satisfy ALL of our current current just with PV or CSP, and so that square milage is already a great deal smaller, as Solar shares the load with Hydro, CoGen, Wind, Tidal, some say Nuclear, whatever.
On top of that, or I should say 'Off the top of that' also comes all the countless reductions we can implement, whether it's efficiency, removing silly redundancies and luxuries, etc. How much can we cut out of this fatty energy demand of today? It's 25degrees out, but my fridge and a separate freezer are both still running, in a house that I PAY to heat around those chilled boxes. How many homes in the summer are being 'Heated' by that same fridge's compressor, as they spend money to cool that house? There's so much we can do that wouldn't even be a major change.. and then, there are the major changes..
Bob
It was in the upper 30s here last night and at least four or five people in my building were running their air conditioners. It got warm enough during the day that those people turned on the AC and it probably didn't occur to them at all that after the sun went down, they could have cracked a window.
These numbers are silly. Look at it this way: each household's electrical needs can be supplied by about 12 120W solar panels. The cost of that would be about $12-$25K, depending on whether substantial storage (batteries etc) would also be necessary. Compared to the cost of a house, that is not very much. There would be commercial needs too, but there is also lots of commercial roof space available. Add a bit of wind and existing nuclear/hydro capability, and you have a perfectly functional electrical system.
This idea that electricity needs to be some massive project hundreds of miles from people is based on expectations for existing coal-fired plants, where there are great economies of scale.
from Backwoodssolar.com:
#5 LARGE HOME / SMALL BUSINESS
$18,000 to $33,000
PRODUCES ABOUT 10 USABLE KILOWATT-HOURS ON A SUNNY DAY
When Backwoods was off-grid, we ran 4 computers 10 hours a day, 3 answering machines, fax, 3 wireless phones, office and stockroom lights, work bench and shop tools. We also had all the usual residential power described in example #4, including several solar electric design refrigerators. A true Sine Wave inverter runs washing machines and power tools. Stereos, ceiling fans and appliances don’t hum. Includes automatic generator start as batteries or loads require. Battery voltage of 24 volt or 48 volt is recommended. 24 volt battery bank requires 6-volt batteries set up in multiples of 4, while 48 volt requires multiples of 8. This is simplified by factory assembled equipment.
SOLAR 2080 WATTS: (sixteen KC130 watt modules on two mounts of eight)
BATTERIES: (12 - 16 Trojan L-16HC or larger Surrettes, and cables)
OUTBACK Flexware 500 POWER SYSTEM: with 1 or 2 inverters
Recommended Generator: Kohler 10ERG
That's like saying ending the obesity epidemic in the US would just require everyone to eat differently.
I'm disturbed about that people are coming up with the same numbers talking about photovoltaics and solar thermal systems. Is this accurate?
I noted that once as well. I think the overall area required is similar, though. I had done a calculation of solar PV once before and came up with something like a 50 mile by 50 mile area, but there was nothing in there for infrastructure. The solar thermal plant has a lot of infrastructure associated with it.
would it?
http://www.calcars.org/calcars-news/657.html
The problem is that you are trying to recharge when solar output is well past daily max. Without a good storage solution, this is a problem.
I am not basing it on us having 100% solar power but you do make a good point. cars could charge at work like Google's solar groves.
We can replace all heavy truck & railroad oil use with 2.x% of current US electricity use via electrified rail.
0.19% of US electricity is used to power the NYC subways, the Northeast Corridor, Long Island RR, subways in DC, Chicago, Philly, Boston, LA, Atlanta, Miami, and light rail in a couple of dozen cities.
Increase that 21 fold (twenty-one NYC subways, twenty-one LIRRs, twenty-one DC Metros, etc.) to 4% of current US electricity demand and such a massive build-out would truly transform the United States !
The lost growth and reduced demand of a severe recession could supply that much (6.x%) "surplus" electricity.
EVs are NOT the best solution, Urban Rail is.
Best Hopes for a de-emphasis on EVs,
Alan