PG&E to buy 550 MW of concentrated solar from world's largest CS plant

Solar has arrived

Posted by David Roberts at 10:25 PM on 24 Jul 2007

Read more about: business | energy | solar voltaic power | renewable energy | California

solar thermal Pacific Gas & Electric is buying 550 MW of concentrated solar. It's one of the biggest solar purchases ever, from what will be the world's biggest concentrated solar plant. The company is trying to conform to California's mandate that it get 20% of its power from renewables by 2010.

According to Mr. [Fong] Wan [VP for energy procurement], about 12 percent of P.G.& E.'s electricity today comes from renewable sources, divided somewhat evenly among wind, biomass, small hydropower and geothermal. (California does not count traditional large hydroelectric dams toward the quota.)

The contract with Solel would add nearly two percentage points to the company's renewable energy total.

...

... Ideally, [Wan] said, solar thermal energy would eventually account for up to 5 percent of the utility's energy supply. The company is on track to meet the 20 percent quota, he said, even if some suppliers do not deliver as promised.

PG&E's paying around $0.10/KWh, "roughly what an average kilowatt-hour sells for at retail to American residential customers." As the demand signal for renewables becomes louder and more steady, I expect that number will fall considerably.

For story: PG&E to buy 550 MW of concentrated solar from world's largest CS plant
16 Comments | Post a Comment

conc solar vs spread-out stuff

What does this have to say about conc solar?

http://environment.guardian.co.uk/conservation/story/0,,2 ...

Whiskerfish

by Whiskerfish at 3:45 AM on 25 Jul 2007

While this is true

It's Southern California Edison or San Diego Gas and Electric which is doing the dishes.
http://www.stirlingenergy.com/breaking_news.htm

PG&E is instead opting for heliostats from Luz II.

http://www.luz2.com/templates/professional/412/main/en/gf ...
http://www.luz2.com/agallery%20presentation/c4123/45365.p ...
http://www.luz2.com/agallery%20presentation/c4119.php

-David Ahlport

by GreyFlcn at 6:53 AM on 25 Jul 2007

Depends on climate and efficiency

Sunny climates about 900 barrels of oil equivalent per acre per year, half that in cloudy climates. Concentrators are spaced apart, like fruit trees.

The PG&E market is a drop in the bucket, and they are not choosing technology, just offering to buy a supply of solar megawatts, unfortunately not solar negawatts.

Heliostats can be located over parking lots, over sidewalks, both sides of roads, on top of buildings, on brown fields, ... creating urban shade while supplying community heating, cooling, and electricity.

by sunflower at 6:55 AM on 25 Jul 2007

Read a little deeper please

Biofuels
A generator burning biomass requires crops from 250,000 hectares to match the electricity output of a nuclear power station. (About 0.2% of US electricity needs)
Solar power
Photovoltaic cells covering an area of 150,000 square kilometres would be needed to meet the entire US electricity need for a year. To power New York city would take 12,000 square kilometres, about the size of Connecticut.
http://environment.guardian.co.uk/conservation/story/0,,2 ...

All the report is primarily saying is that biofuels are a dumb idea.
http://greyfalcon.net/ethanol.png

Wind and Solar are no more massive than existing power plants.

-David Ahlport

by GreyFlcn at 7:00 AM on 25 Jul 2007
[ Parent ]

GreyFlcn, Compare his report...

...to "The renewable path to energy security", page 20; these authors seem to think that solar/wind could be done without using massive amounts of land; also the author you cite was talking about replacing allenergy with wind or solar, not just electricity, which makes the situation much worse.

by Jon Rynn at 8:17 AM on 25 Jul 2007
[ Parent ]

Replacing all energy with solar pv electricity

by sunflower at 8:21 AM on 25 Jul 2007

Energy is not Work

People who forecast the cost of 'replacing all energy consumption with (renewable) electricity' generally do not understand the concept of entropy. Joule per joule, electricity can do more work then a unit of oil or coal. Practically, electricity can do approximately 3x the work of a fossil fuel. Consider home heating. A joule of natural gas provides a joule of heat, but a joule of electricity can provide ~3.5 joules of heat with a heat pump.

-- entropyproduction.blogspot.com

by rmcleod at 8:53 AM on 25 Jul 2007

Not the same energy

Collecting ambient heat is like collecting solar heat, it is another energy source. A solar heat collector will cost less and amplify the heat of parasitic electricity consumption much more than a heat pump. The laws of entropy still apply when all energy inputs are accounted for.

by sunflower at 9:18 AM on 25 Jul 2007

Chose solar over wilderness?

What the article unfortunately fails to mention is that the planned monster solar developments in "The Mojave Desert" will utilize as their footprint thousands of acres of pristine desert habitat that home to thousands of species of plants and animals, including the desert tortoise. The Mojave Desert remains one of last great wild areas in the U.S. These would be scenic and wild public lands (BLM) transferred to private industry. The folly of these plans is that solar development can occur anywhere there is sun, including the rooftops of urban environments as found in L.A. and San Diego. But in this corporate plan, the "desert wasteland" is instead sacrificed, ensuring higher profits for corporations and a higher cost to the consumer. But more importantly, the sacrifice of native plant/animal biodiversity is yet another example of man's way of doing things....a la clearcutting, strip mining, leap-frogging....to maximize profit over wise earth stewardship. I'm against this kind of solar power.

James M. Andre

by jimandre at 10:49 AM on 25 Jul 2007

What would you say...

...if Death Valley was covered over with solar energy systems, and in return, all coal plants were shut down? Would that be a good exchange? In a previous comment, I noted a study that refers to an IEA study that claims that over half of our electricity needs can be met by putting solar on rooftops and facades, although I might also advocate using rooftops for gardens; is it possible to use some parts of some deserts for concentrated solar, which is more efficient than PVs?

by Jon Rynn at 11:53 AM on 25 Jul 2007
[ Parent ]

Desert heat

The desert is not the best location for solar concentrators.

These devices should be distributed near people. Cooling the power cycle for making power is both expensive and wasteful in a desert. A better heat sink is cogenerating power with waste heat applied to heating, cooling, and industry. Solar is very low cost to displace natural gas used for thermal loads.

Further, even expensive land is a small percentage of solar power plant costs, so no worries there.

by sunflower at 12:09 PM on 25 Jul 2007

That's fascinating...

...so you're saying that it wouldn't make sense to take a big chunk of a very sunny area, as in a desert, and generate a huge amount of electricity there? You could put these concentrated solar installations near cities and towns? That's fine with me, I would prefer a decentralized energy grid, I was just under the impression that those installations are so big they need to be in the desert.

by Jon Rynn at 12:21 PM on 25 Jul 2007
[ Parent ]

Just a mirror on a stick.

Concentrator systems can be any size system, from a 1 kW(e) dish to a 10+ MW(e) heliostat field. Size matters on choice of geometry.

There is push, pull, and science. The science wants record breaking efficiencies and performances. The pull wants electrical power (due to government/industry interference). The push wants return on investment.

It is a virgin market so the push, like a kid in a candy store, can choose the most valued customers. From cost, risk, and fast payback perspectives, the best customers are low grade heat consumers, especially electric and natural gas hot water and/or wet steam users.

The concentrator field is sized to the thermal load to be quickly amortized by the thermal load (rapid scale up wants 3 years). High-intensity 40% efficient multijunction pv cells are laminated on the cold end of the receivers to cogenerate some power. The thermal load is the milk, the power is the creme off the top.

A very low cost field of dish or heliostat concentrators + high power would start at $200,000 per acre.

by sunflower at 12:58 PM on 25 Jul 2007

They are as small as a satelite dish(old style)

http://www.sunmachine.de/english/main.html
http://www.infiniacorp.com/applications/clean_energy.htm

It would be far more efficient to mount these units next to buildings where the waste heat could heat water, run AC's, or provide space heating.

My idea is that you oversize the solar collector and feed excess heat into a geothermal well. Then at night or on cloudy days you tap the well and run the stirling on the back end of the cycle.

Storing solar power is as simple as pumping steam down a well. Sure you don't get it all back but when your cool side is colder (at night maybe) the stirling engine still works as if the hot side was still hotter. Solar and geo-exchange is the ideal combination in my book.

Put the Carbon Back

by Pangolin at 12:46 AM on 26 Jul 2007

concentrating solar power and the desert

I'm concerned by James Andre's rejection of concentrating solar power on the basis of concerns for the desert environment. In projecting the potential of CSP in California and other southwest US states, the National Renewable Energy Lab (NREL) and others have tried to exclude environmentally sensitive land from consideration. After excluding parks, wilderness areas, and similar lands along with any land that slopes at more than 1% and any land that is remote from transmission lines, they conclude that if fully developed, CSP in the SW US could supply over seven times the total US electricity usage requirements. The potential is vast, but of course no one is suggesting that all of this potential be developed at anytime soon.

The second thing to say about environmental effects of CSP is that planning processes underway in California now (initiated by the CA PUC) are consulting with environmental groups that are active in the Mojave. At a recent workshop in southern CA, the largest concerns were about the water requirements needed for cooling. Obviously, deserts are not places with a lot of water and it would be a big mistake if CSP plants pulled the scarce water away from the habitat. How that will be resolved is unclear, but there is a possibility to use air cooled plants, though their efficiency would be reduced.

I also want to clarify a couple of things about the technology. First, the PG&E power purchase agreement was for a huge parabolic trough power plant, not for dishes or heliostats. Second, CSP only works in areas with high incident solar irradiation that is available nearly every day of the year. This limits its application to a few arid parts of the world - the US southwest, Spain, North Africa, some places in the middle east, parts of South America, western Australia. A final misconception I've seen in several reports about CSP is that it only provides power when the sun shines. In fact, liquids heated by the sun can be stored for many hours (6-16 depending on the technology) and then used in the evening or during the night to generate steam to spin turbines.

Steve Beckendorf UC Berkeley

by Steve Beckendorf at 5:12 PM on 03 Aug 2007

Water

Obviously, deserts are not places with a lot of water and it would be a big mistake if CSP plants pulled the scarce water away from the habitat.

Well thats one of the obvious advantages of Stirling Dishes.

No water requirements.

-David Ahlport

by GreyFlcn at 6:34 PM on 03 Aug 2007
[ Parent ]

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