Solar thermal power is back! Solar thermal gets less attention than its sexier cousin -- high-tech photovoltaics -- but has two big advantages. First, it is much cheaper than PV. Second, it captures energy in a form that is much easier to store -- heat -- typically with mirrored surfaces that concentrate sunlight onto a receiver that heats a liquid (which is then used to make steam to drive a turbine).
Back in the 1980s, Luz International was the sole commercial developer of U.S. solar thermal electric projects. The company built nine solar plants, totaling 355 MW of capacity, in California's Mojave desert. Luz filed for bankruptcy in 1991 for a variety of reasons detailed in this Sandia report.
For 15 years, no commercial solar thermal plants had been built until the creation of the Spanish system pictured here. Technology Review has published, as an advertising supplement, one of the longest and most informative pieces I have seen on solar thermal, also called concentrated solar power (CSP).
California utilities are also beginning to contract for new CSP plants -- "the resurrection of thermal solar arrays," as the New York Times puts it. In July, Pacific Gas & Electric announced a plan to buy 550 megawatts of CSP in the Mojave Desert.
If you want to read more about this re-emerging form of solar power, the National Renewable Energy Lab has a website with publications on the technology and potential market.
This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.
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Comments View as Flat
Aklemm Posted 7:08 am
30 Aug 2007
Solar-Thermal Projects
The issue with Solar Thermal projects is the land area required and the subsequent need for transmission and distribution of the power.
Solar Thermal is significantly more difficult to do as a distributed combined heat & power application for a couple of reasons.
Land area required
Super-heated steam requires a union pipe fitter to be onsiste & monitor the system while it is pressurized.
Transmission & Distribution/interconnection issues.
Otherwise a great technology that should make a comeback in the sunbelt.
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sunflower Posted 7:11 am
30 Aug 2007
1970s era technology
Concentrator pv supplants thermal engines in both economics and efficiency. I just sent out this missive an hour ago and include here for your update... links are hot photos.
Solar Team --
One hour ago I installed and tested the Lytron 25 pv heat sink. We have zero funds so there is little reliable data. However, I am assuming 40 W/cm2 on Silicon VMJ cells (Bernard Sater, PhotoVolt). The voltage drop was zero so we had excellent thermal management despite non-conductive adhesive layers. I am surprised. Kudos to Bernie!
The assembly will remain in the glass dish this winter for weather and flux durability testing.
-- Doug
http://www.harbornet.com/sunflower/Lytron25.jpg
http://www.harbornet.com/sunflower/dish1.jpg
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sunflower Posted 7:17 am
30 Aug 2007
Steam and mirrors
Land cost is 5% to 10% of system cost. I have been cogenerating heat and power all morning.
Solar mirrors are good in most climates, including Seattle.
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odograph Posted 8:40 am
30 Aug 2007
socal
Those of us in SoCal sprawl still have miles of desert over the hill from us ... much of it between there and the SCE coal plants across the river in Nevada.
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wayneluke Posted 9:40 am
30 Aug 2007
Over the hill
I live over the hill from you. The metropolitan sprawl has hit us as well. The local water districts are wondering if there will be enough water to put through the taps come December. They only got 60% of the water allocation requested this year. It might drop to 28% next year. Yet, the cities keep issuing permits to build new houses.
On the local energy front, SCE is fighting a war trying to get 3000 MW of wind power transmission lines built. They have 3 of several segments approved but the fourth is getting too close to people's property so they are putting up a fight. Its needed to tie in the Antelope Valley local grid though. As it is, I think we have a Luz facility sitting in the desert about halfway to Las Vegas which doesn't have transmission lines to this day.
Also on SCE's website it says they shut down their coal plant in Nevada.
http://www.sce.com/PowerandEnvironment/PowerGeneration/Mo ...
Of course they are still buying much needed electricity from somewhere and it is probably coal. I wouldn't mind a few more concentrated solar plants. It is the tranmission lines that will kill deals though. That and the fact that the desert is a fragile environment as well. Most of the Mojave is under one protective order or another.
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IfOnly Posted 11:34 am
30 Aug 2007
More info
Great post. Solar thermal is a great and cheap alternative. Read more about solar thermal here.
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Jon Rynn Posted 11:57 am
30 Aug 2007
Sterling engines look very interesting...
...according to the EnergyBlog:
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tedyost1970 Posted 1:48 pm
30 Aug 2007
Totally missing the point
I thought (by the headline and teaser) that this article had promise when it started out by saying how solar thermal has often been overlooked and overshadowed by its sexier cousin: Solar PV.
Wow... great point and great start, but the article simply is a description of another glitzy incarnation of solar power: the large scale plant.
Not one word about solar heating for individual buildings: domestic hot water or space heating.
Not one word how cutting individual building/dwelling demands by 20, 40, 60% or whatever makes a huge difference in fossil fuel consumption and resulting economic drain and pollution.
What's wrong? Not everything is solved in some far -off facility with magic power.
The real magic is the power of the individual. The responsibility of the individual to save 5% here, 10% there.
Once we get over the addiction of the quick, somebody-else-can-do-it fix, we have a chance for recovery.
I wish there were a statistic that could estimate how much it would cost to install one 4' x 8' solar hot water collector per family in the United States.
I wish I knew how much fossil fuel that action would save
I wish I knew how much CO2 that action would save.
I wish I knew how many days of war in Iraq that entire program would cost.
In the meantime, I am installing a couple at my house before autumn.
Let's hear more about this, please.
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Jon Rynn Posted 2:23 pm
30 Aug 2007
Some stats...
...are in this article I wrote about electricity use, but do you know how much a 4X8 solar water heater costs and how much heat it produces and how much water it heats up?
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keldred Posted 1:54 am
31 Aug 2007
Don't forget solar cooking
I just got into solar ovens this summer and found that building one not only used up a bunch of scraps in my basement but also was a lot of fun.
Then I brought my oven to work and a couple of my coworkers got excited about it too. Now every sunny day is a solar cookoff. Here is a link that offers a bunch of really good designs http://www.solarcooking.org/plans/
Not only do we not use the microwave much anymore, but the food tastes much better. Unfortunately the good solar cooking season in western Washington is about over, though now I have one more thing to look forward too next summer.
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odograph Posted 2:53 am
31 Aug 2007
sterling
I've been wondering about those Stirling designs, according to this old quote we should be hearing now how the test system went:
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sunflower Posted 4:35 am
31 Aug 2007
Polish the Stirling
Stirling is not moving forward, has a generic problem - no lubrication. This causes engine wear. If it was lubricated and was a VW engine running at 50 mph it would crap out at 300,000 miles, 6,000 hours, 3 solar years, can not amortize. Engine-generator cost would exceed $1/Watt, more like $2/Watt installed with concentrator.
Wrong question. If you could make natural gas from sunlight at 80% efficiency then use that gas to make power 24/7 at 50% efficiency -- why would you use solar thermal power only when the sun shines?
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trock Posted 5:55 am
31 Aug 2007
this is just one article
This is just one article, there are certainly other important ways to make solar energy usable, it just takes time to go thru them all.
Not everybody would be interested to have a solar anything on there house. That might be 80 to 90 percent of the population. (unless there was enough incentive) That's why we need to get to utility scale CSP, so people who only want electricity and don't care it's source, would also get it from carbon reduced sources.
This one from spain, with a center tower and acres of mirrors, is the one that I have read has the lowest cost potential. I think it's the one that should be emphasized.
It's good to see more of CSP' getting put in. If only it could go at a faster pace.
The dish CSP's are to expensive, I don't see how they can make it.
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Jon Rynn Posted 7:03 am
31 Aug 2007
sunflower, Any links on this?
I think they said it sterling was $2/watt. SCE is putting a lot in, I would think they don't have that big of a problem. What are you referring to with 80% solar efficiencyleading to gas? sorry I don't know the reference.
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jaall Posted 7:46 am
31 Aug 2007
Solar thermal
>I have been cogenerating heat and power all morning.
Via Solar? Please tell more. I'm a newbie here, so please copy me at johnaallen@gmail.com
Focused on distributed solar thermal.
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sunflower Posted 8:15 am
31 Aug 2007
I am agnostic on power converters
I looked hard at all of the small heat engine types for 20 years and just gave up. None of them pencil out due to moving parts wear, thermal cycling, exotic high temperature materials, and so on. The main problem is that lubricants can not take the heat. In cooler steam engines the lubricating oil is added to the steam and must be separated back out from the steam discharge.
The recent history of Stirling engines comes from the 1970s plan in Sweden to use United Sterling engines in cars during the OPEC oil embargo. Solar power engineers tried to use these engines because they were to be mass produced in Sweden. The engines failed cost and durability tests and were abandoned for cars, and subsequently shelved for solar applications. Stirling companies were spun off at 5% of former value yet remained promoted by the salvage buyers, now Stirling Energy Systems. That quote on the lifetime of VW engines applied to heat engine lifetime projections came from one of the many CSP conferences we all attended year after year.
Solar power is sexy but not scalable, like what Vinod Khosla said about pv. Lovins on displacing natural gas before making power with solar concentrators said, "You have to learn to fly before making plans to land on Mars". The costs, risks, complexity, and ROI is excellent for solar industrial process heat (a solar program terminated by Reagan, solar concentrators were terminated by Bush). Those solar programs would have saved natural gas using 80% efficient solar concentrator systems. Displacing gas with solar is the same as making gas with solar.
What I can not prove but definitely suspect is that simple low-cost solar energy became complicated high-cost solar power as a method to set up solar to fail. It is damning disinformation concerning the efficacy of solar energy to displace fossil fuels.
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sunflower Posted 8:21 am
31 Aug 2007
john a allen --
cogenerating heat and power
http://www.harbornet.com/sunflower/litxs.jpg
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Solshapiro Posted 9:13 am
31 Aug 2007
Right On
CSP - solar thermal electric generation should be the 800 pound gorilla of our renewables base. On less than 10,000 square miles of the southwest, we can make all the electrical energy used in the U.S. and send it around the country on high voltage dc. This is not to denigrated local use of cost effective technologies such as wind and geothermal. But solar thermal electric generation now seems to be moving down to a cost in the order of 10 cents a kwh and will continue down as it is built out.
Sol Shapiro (Somarl@msn.com)
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Jon Rynn Posted 10:06 am
31 Aug 2007
Sunflower, just to be clear...
...the small (25kw) sterling engines would not work (say on the roof of a big building or ex-parking lot), but might work in a big configuration that SCE is using? I seem to remember that you once said that small csp's could be built, but perhaps I misunderstood - and the lubrication is needed in order to move the engine to track the sun, but it gets too hot to work properly? Thanks!
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sunflower Posted 1:05 pm
31 Aug 2007
Scale up
I don't know if anybody knows lifetime. Every year I hear big stories that never happen. Its an old story.
My lede are heliostats reflecting sunlight to towers for process heat applications. Heliostats are very simple mirrors on poles. The industrial gas saved can then be used for baseload gas turbines, which are scalable off-the-shelf power.
High-intensity pv power can be generated off the tops of the thermal cycles on solar towers. Solar Systems in Oz has drawings of pv towers.
Cooling solar power plants in deserts is a waste of thermal energy, and difficult. Distributed solar cogeneration systems near people are more efficient, lower cost with greater value - heat and power.
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Jon Rynn Posted 3:09 pm
31 Aug 2007
OK, so heliostats...
...that are miniature scale of the Spanish installation, they can be scaled down to, say, the roof of a large building or a parking lot?
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GreyFlcn Posted 3:24 pm
31 Aug 2007
As for a solar you don't often hear about
As for a solar you don't often hear about,
How about "Organic thinfilm solar"
http://www.sciencedaily.com/releases/2007/07/070719011151 ...
http://www.blog.thesietch.org/2007/04/08/organic-solar-ce ...
For all those who are big boosters of biofuels, even the weak efficiency ratings (5.2%ish) of these organic panels, trumps the efficiency of biofuels, even before processing it from solid biomass into a liquid fuel.
http://greyfalcon.net/sugarsolar
_
This is for those who are so concerned that we will run out of raw materials for solar panels.
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guerby Posted 6:42 pm
31 Aug 2007
GreyFlcn
GreyFlcn, you post great stuff here thanks!
Do you have a website with a list of your graphs & documents URLs?
Thanks in advance,
Laurent
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sunflower Posted 12:26 am
01 Sep 2007
Mini heliostats
Yes, I've seen them as small as ping pong balls. The current sweet spot is about 12 feet square. Heliostats over parking lots reflecting to towers over factories is a good image. They can also feed into district heating/cooling and power plants to reduce fuel consumption.
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sunflower Posted 12:49 am
01 Sep 2007
Ideas R Us
Idea Labs - Bill Gross - has one foot heliostats on building roofs.
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Jon Rynn Posted 3:55 am
01 Sep 2007
sunflower, thanks
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WWAGD?! Posted 4:12 am
01 Sep 2007
Eco-Foundries
Good article in WP today about old style "iron works" being used for enviro projects like tidal wave transformers:
http://www.washingtonpost.com/wp-dyn/content/article/2007 ...
"PORTLAND, Ore. -- Oregon Iron Works has the feel of a World War II-era shipyard, with sparks flying from welders' torches and massive hydraulic presses flattening large sheets of metal. But this factory floor represents the cutting edge of American renewable-energy technology."
John Bailo
Sutext:
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Jon Rynn Posted 7:12 am
01 Sep 2007
Bailo, thanks, and idea labs link...
...company called esolar, they claim that covering 1% of the Sahara desert with their systems would provide enough electricity for the whole planet.
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sunflower Posted 8:05 am
01 Sep 2007
esolar drawings news sans news, thanks Jon
Critical cost information needed --
Heliostat installed cost below $200/m2 will blow the pants off coal. Same below $100/m2 in cloudy Seattle type climates. It can be done.
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concerned1984 Posted 12:50 am
13 Apr 2008
nanosolar
I've been a proponent of solar power for 30 years now, but until some one like bush finds a way to keep on getting paid for it(sun power that is)but at least it will be clean & inexaustable! but let's face it,our president & his co-horts are too vested in oil, & have proven that by trading our kids lives for their interest in Iraq? 1st it was weapons of mass destruction(none found),then it was terrorists(got plenty of other countries breeding them)? now it is(a stable Iraq)? the man is a lair & lining his pockets with blood money!Texas needs to build over 150 new coal burning plants, Florida wants nuclear plants? not enough desert in Texas? FED EX runs a shipping plant on solar, with some to spare?& there is plenty of cleared, unused land here in north Florida? almost every roof here could be redone with these new pv shingles, & put lots of people to work? but then the electric companies couldn't justify their price hikes & fuel fees! invest in America for Americans, or soon we will all be homeless!God bless&best wishes in these troubled times.
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concerned1984 Posted 1:34 am
13 Apr 2008
cooling in the desert
why cool at all, just use the heat to run steam turbines & make more power? solar hot water systems have been in use since the 70s, i had one on my roof!stop trying to make excuses why solar can't be used, unless you like choking on the air you'll be breathing, in 10 or so years? or maybe you own oil futures? & now pv shingles are available, there is no reason every home should have them!
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concerned1984 Posted 1:38 am
13 Apr 2008
rooftop solar
tell that to FED-EX???
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concerned1984 Posted 1:42 am
13 Apr 2008
the truth the "OIL MAGGITS"
they would rather destroy our bio-sphere instead!
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fireofenergy Posted 10:33 am
17 Oct 2008
Transmission
I heard that such lines cost 1.5 million per mile. If say, 50 sq mi of land was to be used for CST (concentrated solar thermal) plants, and assuming that each 7 sq mi = 1 gigawatt (probably less but with much higher capacity with molten salt storage), and assuming that it cost $4 per watt, then $28 billion for a small percentage of America's needs but at least 28 times than cost of the lines! If everybody paid a dollar a month for lines, then over 100 miles worth every month!
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WWAGD?! Posted 11:18 am
17 Oct 2008
Volcano!
Who said Palin wasn't an innovator?
http://volcanism.wordpress.com/2008/06/25/geothermal-powe ...
http://eruptions.wordpress.com/2008/06/25/geothermal-powe ...
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