Solar coal: A near-term solution

sanfrancisco.bizjournals.com
August 27, 2009

Abengoa Solar, a utility-scale solar company building big solar thermal power plants in the deserts of Arizona, announced today that it's going to build a demonstration of its solar thermal power plant technology connecting to a coal plant near Grand Junction, Colo.

Solar thermal technology uses big arrays of mirrors to heat water that turns turbines and creates power. Abengoa says its technology can be used to increase the efficiency of coal plants and lower the greenhouse gas emissions of a coal-fired power that otherwise would be produced when coal is burned to make the steam. The Lakewood, Colo., company has partnered with Colorado utility Xcel Energy on the 4 MW demonstration project.

Solar thermal for coal plants and old combined cycle gas plants – the dirtiest electricity producers out there — is billed by the solar thermal industry as a way to lower the greenhouse gas emissions of coal plants quickly and cheaply. Much of the delay in getting solar thermal plants built can be attributed to problems getting building and land permits and long waiting lists for new steam turbines. However, it is much easier to get permits for installing solar thermal on existing coal fired power plant sites than it is to try to permit new land for stand-alone solar thermal plants. And, turbine delays are a non-issue since coal plants already have turbines.

Mountain View-based Ausra already demonstrated this solar-coal hybrid model at a coal plant in Australia and is pitching it to power plant owners and operators and manufacturing facilities as a near-term solution to increasing efficiency and lowering the environmental impact of coal plants in the U.S.

Katherine Potter, vice president of communications for Ausra, said the company can get a solar thermal plant installed at a coal plant in six to 18 months depending on a project's size. solar thermal power can raise output at peak sunlight by 5% in super sunny places like Phoenix, Ariz., and it can decrease a plant's CO2 emissions between 30,000 and 1.7 million tons per year. "I think there's certainly a way to address emissions earlier rather than later," Potter said.

Detractors might say that adding solar thermal doesn't do much to discourage the burning of coal to produce energy and that we should focus instead on new renewable energy solutions. But the fact is renewable energy is still far more expensive than that from coal-fired and natural gas power plants. And as many, many energy officials and industry executives will tell you: coal isn't going away anytime soon – not while America remains opposed to paying a whole lot more for electricity. Finding solutions that will at least lower the impact while renewable energy solutions continue to be developed, may be our best bet.