POWER TOWER: By focusing sunlight with mirrors onto central towers, such concentrating solar power plants turn the sun's heat into electricity.
Image: Courtesy of eSolar
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In southern California's Antelope Valley, 24,000 silver-bright mirrors have been positioned to reflect light on two 50-meter-tall towers. And at 11:08 A.M. local time Wednesday, this concentrated light heated steam in those towers to turn a turbine—the first "power towers" in the U.S. to convert the sun's heat into electricity for commercial use.
Dubbed Sierra SunTower, the power plant can produce five megawatts, enough to power roughly 4,000 local homes at full capacity—and provide the modular blueprint for larger plants in California and New Mexico, according to eSolar, the Pasadena start-up behind the power plant.
"We call this a commercial demonstration," says eSolar senior vice president of engineering Craig Tyner. "A 46-megawatt commercial design will incorporate 16 of these towers, two of which we have at Sierra" as well as more than 200,000 mirrors capable of generating at least 90 gigawatt-hours of electricity per year.
Harvesting the sun's energy as heat is hardly a new idea: During the energy crisis of the 1970s, designs for solar thermal power plants took off. And ever since 1984, vast arrays of curved mirrors have been concentrating the sun's rays on pipelines filled with synthetic oil at the Solar Energy Generating Systems (SEGS) power plant in California's Mojave Desert. But power towers, at least theoretically, would be more efficient than these so-called parabolic trough designs, because all the heating and fluid is contained in one central tower.
The key to eSolar's design are the mirrors—known as heliostats in the concentrating–solar power industry. By precisely calibrating the mirrors with computer algorithms driving shoe box–size motors, eSolar can build its sunlight-harvesting power plants with many more small, flat mirrors, roughly one square meter in size, as opposed to the large, curved specialty mirrors employed in other designs. "We're using more software algorithms and less steel," says Bill Gross, CEO of the Google-backed solar company who, at the age of 15 in 1973, started Solar Devices, a firm which sold plans and kits for solar power, before pioneering pay-to-click advertising for search engines in the 1990s.
But the multiplicity of mirrors could also prove the technology's weakest link. "The question is going to be the maintenance of all those heliostats," says Mark Mehos, program manager for concentrating solar power at the U.S. Department of Energy's National Renewable Energy Laboratory in Golden, Colo. "You have orders of magnitude more heliostats that you're going to have to maintain and that you're going to have to track."
Sierra SunTower has a number of environmental points in its favor in addition to the renewable energy it generates. It employs reclaimed water for its cooling and was built near existing transmission lines on what used to be farmland rather than the pristine desert areas nearby that have provoked opposition to some other planned solar power plants. "This model makes the destruction of public lands unjustified," says David Myers, executive director of nonprofit environmental group the Wildlands Conservancy. "There are 200,000 acres in southern California of lands that are degraded or disturbed that we support for solar electricity."
Gross, for his part, estimates that the entire state of California's peak electricity demand could be generated from an eSolar field of 65 square kilometers. That electricity would cost no more than 13 cents per kilowatt-hour, the current average price of power in the state, although the company refused to reveal how much the existing plant cost to build or what price Southern California Edison is paying for the power. "This is a second industrial revolution to power the planet cost-effectively from the sun," Gross says.
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59 Comments
Add CommentAt $0.13 per kwh for a full scale solar plant it's only about 2.5x the cost of gas fired electricity at current prices. And that's in an area with bountiful sunshine. Well, Californians are accustomed to paying more for everything, so I guess they won't mind.
Reply | Report Abuse | Link to thisThis screams for a Sterling engine application.
Reply | Report Abuse | Link to thisTwo different numbers are used here. The two commercial operations described, one lists as 46 megawatts, the other is described as "90 gigawatt hours per year".
Reply | Report Abuse | Link to thisThere are 8766 hours per year (365.25 * 24). In "continuous" operation, that would mean ten megawatts. If you assume 50% sunlight hours, it's more like 20 megawatts, and if you consider peak vs. off peak sunlight, maintenance times, rain days, etc... that 46 megawatt number looks very close to the same then for both plants.
If my math is even close to right, using the "90 gigawatt" number is extremely misleading even if the qualification "...hours per year" is added to make it technically accurate.
So, at 46 megawatt production during sunny days (which admittedly are the times when the grid needs the most power, so the higher priced resources at that time does make some sense) --- the figures provided say 5mw = 4000 houses. This would then suggest that the commercial plants could generate electricity for the daytime demand of around 45000 houses.
It's great work, but not game changing by any means.
For the same of quick discussion, lets say roughly half of those are sunlit
Oh come on soccerdad, its a new technology. It's bound to be more expensive initially. If/when it becomes more widely used you will get the efficiencies of scale as well as improved technology and manufacturing techniques to bring the cost down.
Reply | Report Abuse | Link to thisIts efficiency can be boosted a bit. Given that the best photovoltaic cells only convert to electricity about 40% of their input and they reflect the rest, they could be used as the basis of mirrors. Absorb what can be absorbed, and convert it directly to electricity, and reflect the rest to creat superheated steam.
Reply | Report Abuse | Link to thisGreat idea Dimitris! I am sure it will be looked at in the future. I am encouraged at how much more talk about green energy we hear with this administration. That is a great start. With more funding will come more improvements. Think where the fossil fuels were 100 years ago. What needs to happen for this really to take off is for the oil conglomerates to venture into the business of renewables more seriously and I can see that starting to happen. Still, we have a long way to go.
Reply | Report Abuse | Link to thisEvolution involves a struggle to achieve beneficial adaptations. But if someone doesn't believe in evolution (it's ongoing) they probably aren't going to be enthused to participate in it. Rather, there's a good chance they want to return to the "glory days". May I suggest a cave or a thatched hut?
Reply | Report Abuse | Link to thisThe main problem with solar energy, on a large scale, has always been energy storage. The sun doesn't shine at night, therefore, you do not have any electricity unless you have built an energy storage system, or other means to produce electricity at night (This also pertains to extended overcast or cloudy days.) On a small scale, this is not a problem. However, when you have charlatans promoting solar energy on a mass scale for the state of California, this becomes a huge problem that they do not want to address.
Reply | Report Abuse | Link to thisAdditional problems with solar energy, even on a small scale, have been the low efficiency and high costs. You know the 13 cents/KwHr is a pipe dream when the CEO (Mr. Bill Gross) will not reveal his existing plant costs.
I am in favor of renewable energy sources, but I think the various participants (solar/wind/biomass/geothermal) should be forthcoming in releasing their present installation costs, and their continued maintenance costs. Wise decisions in the renewable energy field cannot be made when the various participants conceal their actual costs in order to further their own agendas. And when the participants make outrageous claims (13 cents/KwHr) while blocking the release of their present costs; they look like quacks to anyone who has ever worked in the energy industry.
We worked out the physics of this project 5-10 years ago. Others had the project worked out 20+ years ago. There
Reply | Report Abuse | Link to thisseems to be some obvious delay lags with government (politics) and industry (money). Let us forget the past delays and continue to move onto the future. Neat project. We feel
that at least some 1st class scientists and engineers understand. No longer a voice in the wilderness.
Good point Mr. Clemen.
Reply | Report Abuse | Link to thisThere is one sure way to know if something is viable. That is to let it stand on its own without government subsidies. If it is economical, it will be exploited.
I know this won't be popular with many on this site. Many otherwise intelligent people seem to be skeptics when it comes to the science of economics.
I like your idea private and public monies. Some people
Reply | Report Abuse | Link to thissay the government is already into 8 trillion $ to cover
common morgage banking & housing projects. I read Adam Smith's Wealth of Nations. In my humble opinion, your division between public and private monies and market efficiency rings from the plutocratic dark ages. If Edison followed your ideas we would have no light bulb. Peace.
he would of died broke and in ob;ivious name. Wake up.
Energy storage is as important as generation. There's a project plan near me at the site of a decommissioned nuke plant that's nearly green field now. It takes advantage of the distribution infrastructure and the land mass. The idea is during the day, to allow massive volumes of ocean water to fill a huge underground cavern, turning turbines the whole time, and generating power during peak periods. At night, during OFF PEAK times, power is used to pump out the water. The thing is, it generates power when it's needed, and uses power when there's excess on the grid.
Reply | Report Abuse | Link to thisEven though it is a NET LOSS of power, the gain happens when it's needed, and the loss happens when it's not. This serves to help balance the grid.
I'm fascinated by this approach, and hope it works.
Have you ever lived/been to the high desert... Sun is something they have plenty of. Having spent two years living just north of Barstow, I don't think your estimations of available light are accurate.
Reply | Report Abuse | Link to thisAdditionally this article fails to mention the TWO previous solar-thermal plants built 60 miles away, just east of Barstow. Their numbers were less impressive, but they were also a part of a pilot program sponsored by DOE and Edison Power. Wiki "The Solar Project" for more.
In the late 1970's Sandia built a more advanced system, the biggest problem in keeping it operating was the computer control system. Poor basic design, a central computer to control the helostats is very difficult to make work.
Reply | Report Abuse | Link to thisI designed a much cheaper and positive guidance unit for each helostat unit, that made each helostat semi independant and easily aimed. In 1984 that was a solution to a no longer existing problem.
this is a nice start, but really there should be solar collection panels on every building; no one should have to actually PAY for electricity.
Reply | Report Abuse | Link to thisthis is a nice start, but really there should be solar collection panels on every building; no one should have to actually PAY for electricity.
Reply | Report Abuse | Link to thisTo Mr. Clemen and Soccer Dad:
Reply | Report Abuse | Link to thisThe entire energy industry has been goverment subsidized from the begining. So what is the basis of your concerns?
The entire energy industry is government subsidized. So what is the basis of your concern?
Reply | Report Abuse | Link to thisI wish this project success. At the same time I suspect this particular concept, which is an incremental improvement of something developed 30 years ago, will not compete with newer solar energy concepts and configurations which are currently being piloted. It has too many moving parts that require high precision spread out over too large an area. It has too many bottlenecks in the tower components. it needs too much water. And finally it has too low overall conversion efficiency.
Reply | Report Abuse | Link to thisAlty53,
Reply | Report Abuse | Link to thisI have not heard of what you speak. Tell me, has the DOE sponsored projects to demonstrate that gasoline is feasible to be used in automobiles? Or that coal or natural gas is an appropriate fuel to generate electricity? Are there demonstration scale projects figuring out how to make a technological breakthrough to enable the burning of fuel oil in a boiler?
Frankly, I'm tired of these claims of government subsidy for conventional energy sources without a single shred of evidence that it is really so. OK, the U.S does patrol to keep shipping lanes open. But that benefits all shipping, not just oil. I'd like to hear some valid examples of specific subsidies to fossil fuels.
Unfortunately Dimitris, it doesn't work that way. Absorption and transmission of light are complementary figures for all materials, along with reflection. To put things in a simplified form, transmission and reflection are two opposing processes which account for all light that hits a surface, or
Reply | Report Abuse | Link to this1 - T = R Think of 1 as 100% of the light in a system, and you'll get the idea of how these two variables relate to each other.
When 1 > R + T, you have some absorption in the system which is taking away some of the light before it can be reflected or transmitted.
So 1 -T = R +α
As you can see, the only way a material can be a good absorber is if you maximize α as the expense of T and R (there are ways to do this without affecting T and R since the absorption coefficient of a material is an imaginary value). Even if T = 0 you still are stuck with a balance between R and α. So it isn't possible to have a material which is both an excellent absorber AND an excellent reflector, which is why photovoltaic cells can't be used to redirect sunlight at these towers while harvesting it for power.
@DHE - yes, grew up in Phoenix, and btw: you miss my point. If my estimates of available light are too LOW, then the actual megawatt generation of the plan is lower, not higher because that crazy 90 "gigawatt hours per year" figure is divided across more hours.
Reply | Report Abuse | Link to thisDid a little calculation one day. CIA World Factbook estimates the US used 4x10^12 kWh last year. Given roughly 1 kW/m^2 from the sun, about 5 hours of direct sun per day, 10%-15% efficiency (I forget what number I used), I figured it would take 100 million installations of 10m^2 each to supply 10% of the domestic electricity supply. Basically amounts to laying a photovoltaic array on every rooftop.
Reply | Report Abuse | Link to thisThe only way to do solar power right would be to make it a ubiquitous consumer commodity. Large dedicated facilities simply don't have the energy density, so I think this sort of system is ultimately a dead-end.
It's new technology? Focusing mirrors on a tower to heat water is new technology? Did you not read the part about how we've been doing this since 1976? That's 30 years. The "new" technology here is little motor-driven mirrors connected to computers. In other words, control systems that are at least 15 years old technology.
Reply | Report Abuse | Link to thisNo, the issue here is what it always is with solar power. Low energy density. Which means high materials cost to gather it.
"The entire energy industry has been goverment subsidized from the begining. So what is the basis of your concerns?"
Reply | Report Abuse | Link to thisTypical. A tax incentive is nothing more than the state allowing a company to keep more of its own money. If you think that's a subsidy, then your entire paycheck is nothing more than a subsidy.
Galaxy_man, thanks for the explanation, and it makes sense. However, you are talking about perfect absorbers and perfect reflectors. Current photovoltaic cells convert up to 40% (usually quite less) of the input to electricity, and waste another 10-15 % as heat. The remainder is already reflected back. It is this reflected "by product" that I refer to, which I think could be focused in a similar way. I might be wrong, but I think the numbers check out.
Reply | Report Abuse | Link to thisI am interested in the idea that incoporating the myriad of secondary costs for fossil fuel power would level the playing field with renewable energy. Don't Americans spend billions on the effects of poor air quality and elevated levels of greenhouse gases?
Reply | Report Abuse | Link to thisExploration, property aquisition, excavation, refineries, R&D, Production, distribution, taxation... each of these steps and more has people hired to pursue whatever public money they can to lessen these costs. Energy companies are not small-time mom & pop operations. If they can spend a million dollars pursuing a million and five dollars, they do it. Those companies that didn't, lost out to those that did. There's not even much to-do about it, because it's status quo. For better or worse, our nation functions on oil. When we need to send continual military personnel and equipment to patrol foreign oil fields, we go. The cost of all this in money and lives puts the total cost per barrel at an unbearable, prohibitive rate. Because that cost is so high, we say the burden shouldn't rest solely on the shoulders of the few who are purchasing it directly, but all citizens who purchase goods and services downstream of it, as well as those who enjoy the *potential* of being able to be a part of the game. You want copies of the bills? Most of the information is public, take five seconds and lift a finger and do a search of your own.
Reply | Report Abuse | Link to thisUntil very recently, we spent less annually on all alternate energy research combined than we spend on a single apache helicopter in defense of oil fields. That alternate energy has achieved as much ground as it has with this little help and support, makes all of them far better performers than oil, which is not remotely feasible on its own two feet.
The number of things you'd have to ignore on a daily basis to not be aware of how we get our energy is quite large. How embarrassing.
"CIA World Factbook estimates the US used 4x10^12 kWh last year...."
Reply | Report Abuse | Link to thisYes. That also covers every car, truck, construction vehicle, plane, jet, and military craft, in the country. Powering them all with solar would mean you're planning on running them all on electric motors?
The power used by residences and businesses is far less than that total.
Remember Soccerdad this is Scientific American so if its evidence you want then it is evidence you shall have:
Reply | Report Abuse | Link to thisThe following data is from the Federal Government Budget from the year 2002.
Mining Industry: Total subsidies equal $3.5 billion per year. Mining companies are allowed to search for minerals on public lands, patent those rights to mine at 5 cent per acre and pay no royalties to the national treasury. Mining companies are not required to clean up the land they have mined and the mining companies can take the Reclamation Deduction, the Percentage Depletion allowance and the Accelerated Depreciation Allowance as a tax write off.
Oil and Gas Industry: Subsidies equal $2.4 billion per year:
There is the Oil Depletion Allowance, the Intangible Drilling Cost Deduction, and the Enhanced Oil Recovery Credit. In addition there is a giant indirect subsidy to the Auto and Oil and Gas industry. The public highway system paid by tax payers make the sale of millions of cars and the gasoline refined from oil that fuels those cars possible.
Nuclear Subsidies equal $7.1 billion per year: The Federal Government provides the nuclear industry with most of its fuel and waste disposal, research, and insurance coverage. The US Enrichment Corporation (USEC) was a government corporation before it was recently privatized at a government loss of about $2 billion. The DOE continues to take large amounts of nuclear waste from USEC and stores that waste at public expense. Also remember Yucca Mountain in Nevada and what that cost the tax payers?
I could go on soccerdad but you get the point.
I was referencing subsidies for fossil fuel production, not nuclear fuel or mining (although I guess some of those $ could be going to coal companies). As for the items you reference in regard to Oil & Gas "subsidies". These are not subsidies at all. They are tax credits and deductions - items which reduce taxes required to be paid.
Reply | Report Abuse | Link to thisHere's a fact: ExxonMobil paid $112 billion in taxes in 2008 alone. This is one oil company and it paid $112.0 B in comparison to your supposed subsidy of $2.4 B for the entire industry.
A subsidy is paid to encourage someone to do something which is uneconomical for them to do on their own. That's the name of the game in solar - and it is a game. The name of the game is pound the hapless taxpayer.
To Me-Tech2
Reply | Report Abuse | Link to thisIsn't that what happened to Tesla.......
hotblack,
Reply | Report Abuse | Link to thisYour post suggests that you are knowledgeable and passionate, but its content is overshadowed by your self-righteous and scolding tone. How does your comment address the article or another comment specifically? Do you have any constructive suggestions or potential solutions to offer?
"...A subsidy is paid to encourage someone to do something which is uneconomical for them to do on their own." Without the tax credits and deductions the energy industry would go under so the government is preventing the decline of those industries through its taxation policies. Ergo they are subsidies
Reply | Report Abuse | Link to this"ExxonMobil paid $112 billion in taxes...."......do you really want to stand by that statement?
The name of the game is this: There are no "free markets." There are oligopolistic markets (particularly in the energy sector) that are government protected through subsidies (of which favorable taxation policies are part of the game).
My point is this: Subsidize the solar industry (and the all other green industries) by reducing the subsidies for the oligopolies. The tax payer is getting pounded by government protectionism for the oligopolies. So why not move toward a new energy regime which will be far less environmentally degrading?
eSolar does not use molten salt as far as I am aware. I Could be wrong but I searched and searched for indication that they do but couldn't find it. Molten salt is the real game changer for solar thermal because it allows for nighttime production. If they are not using molten salt then none of their great strategies in technology or land procurement will amount to much. They would be a force to be reckoned with but as far as I know they don't. Until they do they will only be half way there.
Reply | Report Abuse | Link to thisI also would like to point out that I am fairly sure there is an inaccuracy in the article. I am fairly sure there have been a couple of power towers in the US before this. For example Solar One and Solar Two as well as a few recent ones in the southwest.
We should all be quiet.
Reply | Report Abuse | Link to thisThese complaints about government and their kick-back good old boys in the energy industry may get you the death penality in North Korea. This is spy talk.
All american kids need polution in their food to grow up strong and brainwashed.
Free price for electric air conditoning?
What is 6 inches between American good old energy boys and their foreign (forgot the name for foreign energy theives).
Peace.
I believe that esolar is not claiming to be the first power tower in the U.S., only the first commercial plant. Solar One and Two are actually the same facility (Solar Two added a molten salt system to Solar One) and there is a test facility at Sandia Labs in New Mexico.
Reply | Report Abuse | Link to thisI have discussed the issue of molten salt and thermal storage in general with folks at Esolar. Their facility is strictly a steam turbine w/o thermal storage. They explained that their goal was to tackle one challenge at a time. Their pilot facility in Lancaster was built to first tackle the problems that most facilities face with costs, time, and materials and to prove that they could deliver a lower cost kwh. Given that they seem to have accomplished this, I suppose we can wait to see if their next success is in the implementation of thermal storage to their future projects.
Hello EKW3710
Reply | Report Abuse | Link to thisYou mention COST TIME MATERIALS. This is one of best parts of their system.
Economic effiency is by mass production numbers.
Thermodynamic limits are another subject.
Cheap to manufacter. Easy to repair and maintain.
This in my opinion is the bang for the buck.
I like math and physics and mechanics and themodynmaics like many people.
Mass production in China plants can move project up
economic latter.
Why calculate last joule of perpetual motion energy?
Why not calculate first joule of mass production facilities in China?
Peace.
Sorry, EW. That was about as nice as I could be. Perhaps I will be more blunt regarding Scooterdads posts in the future.
Reply | Report Abuse | Link to thisI actually know someone who now sells wind powered street lights, technology has come a long way. With a lot of stimulus money being pointed in this direction, expect a lot more.
Reply | Report Abuse | Link to this<a href="http://watchesandreviews.com">Watches Reviews</a>
Solar arrays such as these are a player in the overall energy scheme but unfortunately are not a major contender (at this stage due to the low efficiencies). However, a good avenue for deploying solar arrays is on building rooftops (outside of major air traffic pathways). Utilization of existing rooftops allows for double use of existing land areas while providing a potential incentive for the property owner. Nuclear and wind power are still our current best bets for green generation, but all types of generation capability will be required.
Reply | Report Abuse | Link to this1. The first CD recorder from Sony retailed at approximately $10,000 US.
Reply | Report Abuse | Link to this2. Eficiency is not paramount when the fuel is free.
3. It should also be noted that using current siumple technologies there is no need for batteries to store electricity for night use.
Soccerdad: This isn't about economics, it's about survival of the species, and our chances don't look very good. Too much talk, not enough action.
Reply | Report Abuse | Link to thisThe species is doing just fine thank you.
Reply | Report Abuse | Link to thisAll commercial activity comes down to economics. If the economics don't work, ventures die or must be subsidized. If subsidized, our overall standard of living will go down as we pay more for less. Some are willing to accept paying more for less to avoid future highly uncertain consequences. Some are not.
There is not much value in technology which is less productive than the technology it is replacing. This whole venture has given us a technology that can provide electricity for over 3x the cost of competing technologies. Not very interesting.
.
stueysplace
Reply | Report Abuse | Link to thisEfficiency is important whether the fuel is free or not. Capacity factor (the amount of time the generator is actually run to produce electricity) is also important. If you have to build 2 times the amount of wind generation because wind is only half as efficient as hydroelectric plants; this means wind electricity is more expensive than hydro electricity. Now if you add in the cost for energy storage facilities and/or extensive transmission lines because the capacity factor of wind generators is only 25 to 30%; you have another large cost added to your electricity bill. When comparing renewable, zero emission generation facilities; hydroelectric power wins hands down over wind generation because of the higher efficiency and higher capacity factor.
If you utilize the same arguments to compare wind generation to coal fired plants; wind generation has slightly higher efficiencies. However, coal generates cheaper electricity rates because it has a much higher capacity factor, and does not require energy storage facilities even though you must pay for the fuel. The argument then resolves itself to how much you (the consumer) are willing to pay for zero emission, renewable energy. These arguments are presently clouded because most wind generation facilities, as well as solar facilities will not release their maintenance costs, tax incentives, etc. etc. to identify their "real" cost to the consumer.
I would also like to know what "current simple technologies" you are referring to for energy storage. On a large scale (thousands of megawatts), the only proven (historically) technology is pumped storage. There are no large (over 100 MW) thermal storage plants; and only two existing Compressed Air Energy Storage (CAES) facilities in existence. Are you referring to small scale? And what is it?
I would prefer if they used the energy to create Hydrogen. That would allow them to use energy day and night.
Reply | Report Abuse | Link to thisPassionate yes. But knowledgeable??
Reply | Report Abuse | Link to thisBut there is little that is new in this. Its NOT "new" technology! France built a solar furnace on a hillside in the south many years ago - and its powerful enough to melt steel and concrete!
Reply | Report Abuse | Link to thisMr. Clemens -- Molten salt systems have been shown store energy efficienctly (low losses), cost-effectively and environmentally low-impact. This enables CSP to now be used "on-demand" and the electric utilities are loving it.
Reply | Report Abuse | Link to thisAll others -- Enough debate, the proof is indeed in the pudding: Are utilities now investing in this technically-feasible, economically-viable, and environmentally-sustainable technology? Yes, they are.
Mr. Clemens -- Molten salt systems have been shown store energy efficienctly (low losses), cost-effectively and environmentally low-impact. This enables the CSP tower tech approach to be used "on-demand", and the electric utilities are loving it.
Reply | Report Abuse | Link to thisAll others -- Enough debate, the proof is in the pudding: Are utilities investing significantly in this technically-feasible, economically-viable, and environmentally-sustainable technology? Yes, they are.
A lot of these economic arguments seem to miss the point that global warming is real. Yes coal and oil are both cheap and plentiful but we are paying a price of environmental disaster. The price of carbon emmisions will go up whether you like it or not and that will change the economic balance to other technologies. Therefore, as a country we need to invest in research and development of all renewable sources so that we are positioned as a global leader in these technologies. My personal favorite is is the use of genetically engineered algae for direct continuous production of ethanol and biodiesel being worked on by Algenol Biofuels, Catilin, and Synthetic Genomics (Craig Venter's company) with deep pocketed partners such as Dow Chemical and ExxonMobil.
Reply | Report Abuse | Link to thisMirror Guy
Reply | Report Abuse | Link to thisTo my knowledge there are only two existing commercial power plants that use molten salt storage. One is a 17 MW plant built in Spain, and described in the technical paper "Central Receiver System (CRS) Solar Power Plant Using Molten Salt As Heat Transfer Fluid" by J. Ortega, J. Ignacio Burgaleta, & Felix Tellez. This plant was the first commercial CRS plant with molten salt storage, and was subsidized by the Spanish legislature to help consolidate the technology for future higher capacity plants. There is now a larger 50 MW plant, called Andasol 1.(Reference "How to Use Energy At Night, Feb 18 2009 Scientific America). Once again this is a total of two plants, which means that utilities are not exactly jumping on the bandwagon.
Altho they store energy efficiently with the molten salt (over 90% efficient), their total efficiency from the solar cells to the generation of electricity is a maximum of 20%. This is very low compared to hydroelectric plants with an efficiency in the range of 85 to 90%, or even wind generation in the range of 40 to 50% efficiency.
Moreover, these plants are not yet cost effective because they are highly subsidized. The article on Andasol 1 in IEEE Spectrum Oct 2008 quoted a "subsidized" price of 27 cents/KwHr. That's a very expensive price for electricity.
However, your last point is valid, i.e., they are environmentally low impact. It just depends upon what price you are willing to pay for electricity.
Calling this the first power tower is not accurate. I visited Solar One, near Barstow, CA, in January 1986. Solar 2 followed. Both are on Wiki for more info. These were Sandia/DOE solar projects from the Carter Era, along with the Solar Total Energy Project near Newnan, GA, a concentrating collector array with a steam turbine backed by natural gas for steam production in low- or no solar hours. All these projects were killed by the Reagan era, along with taking the collectors off the White House. The Swiss film in production, A Road Not Taken, and web site roadnottaken.info Also, the 1913 Egyptian solar engine project, near M/aadi, south of Cairo, should be noted: sun1913.info
Reply | Report Abuse | Link to thisYou say this is the 'first' power tower in the U.S.!!! Whatever happened to the Solar One project (somewhere in California), which we visited as alternative energy trainees in 1984?!?!?
Reply | Report Abuse | Link to thisIf the green energy community looked seriously at what is possible they would see the answer staring them in face ! Lt. Col Tom Beardin . This man has stated the solution repeatedly while the world look's the other way. Too bad ! CHECK HIM OUT ! It just may open your eyes to a realistic approach!
Reply | Report Abuse | Link to thisat the tri-cities, washington sterling engines are already being assembled with solar reflectors and sold. $15,000 per unit. they use one mirror, thus eliminating the maintenance on multiple heliostat controls. however, look at wind and temperature specs. their sterling engine looks good. i don't know their current price per kw hour nor life expectancy nor average maintenance costs. they use helium instead of water/steam or sodium in the sterling engine.
Reply | Report Abuse | Link to thislooking at the photo and judging by the height of the 50 meter tower, i estimate that to produce 5 megawatts it is taking up 740000 square feet of mirror space plus surrounding maintenance space/tower space. i believe the sterling engine produced in the tri cities uses about 200 square feet plus maintenance space and produces 3kilowatts. do the math and see the efficiency difference. here's the webpage http://www.infiniacorp.com/
Reply | Report Abuse | Link to thisHey alty, I'm sure youre not reading this as your last post was in August but I had to correct you on Yucca Mountain.
Reply | Report Abuse | Link to thisThe cost to US taxpayers to research Yucca Mtn has been $0.00. This was paid by (private) utility companies (nuclear operators) in the form of a $0.01/KWhr tax on generation. (See the Nuclear Waste Policy Act). The money was designated to be spent on waste disposal, but it never was... $20 billion is sitting in an account while Congress sits on their hands without a waste disposal policy.
While wind and geo power systems are great ideas,all it takes is one big volcano to put all solar power systems out of action,for an unknown amount of time.
Reply | Report Abuse | Link to this