The U.S. Department of Energy announced plans on Monday, December 17, to provide as much as $20 million in funding to help develop a new class of concentrating solar power plants tied in with existing fossil fuel-fired generators.
Unlike the more common photovoltaic solar systems, CSP produces power by using sunlight to heat water, which is then used to turn a turbine similar to those used in coal-, gas- and oil-fired power plants. The basic idea of these hybrid solar plants is to reduce the infrastructure cost for CSP by attaching them to existing turbines, and then using more easily controlled fossil fuel-fired generators to compensate for the intermittent nature of solar power.
The DOE estimates that the U.S.' existing power plants could readily incorporate anywhere from 11 to 21 gigawatts of CSP capacity, providing clean power to between 3 and 6 million homes while significantly lowering emissions from the original plants.
As part of the Obama administration's SunShot Initiative, designed to make solar power more practical, the DOE will provide up to 25 percent of the cost of four different projects intended to support the development of these hybrid plants.
Technological hurdles
Specifically, the DOE is seeking to hammer out thorny technological limitations rather than to promote new capacity in the near term. For example, earlier this year, General Electric introduced a new highly efficient, but extremely flexible natural gas turbine that it hopes could be used to better account for variations from intermittent power. Though CSP suffers from less dramatic fluctuations than photovoltaics, these hybrid plants will nevertheless need relatively responsive generators to account for the fluctuations that do occur, particularly for those systems incapable of storing energy for release at night.
GE has already launched one project with these new turbines in Karaman, Turkey, though the first of these new hybrids was introduced in an Israeli Kibbutz in 2009. That relatively modest project was only intended to provide power for fewer than 100 homes, but the Karaman plant will be a sprawling 522-megawatt natural gas hybrid that incorporates 50 megawatts of CSP and another 22 megawatts of wind turbines. The wind turbines obviously do not tie into the same infrastructure as the solar system, but will be able to take advantage of the fast-acting gas-fired generator to balance out its production.
U.S. still skeptical
Despite the prominence of CSP in some other countries, notably Spain, the U.S. has been slow to adopt the technology, largely due to comparative cost advantages of photovoltaics.
The Solar Energy Industries Association reported in its annual review that, by the end of 2011, the U.S. had only 516 megawatts of CSP, compared to nearly 4 gigawatts of photovoltaic capacity, with growth since then reflecting a similar disparity.
Still, GreentechMedia reports that there are several major hybrid-CSP projects in the works, including one proposal in Nevada that would add as much as 95 megawatts of solar to a 1.1-gigawatt gas plant. The DOE efforts could spur further developments, if any of the projects successfully ease implementation.
These types of hybrid projects could create a significantly more complicated picture of energy production around the U.S., as generator operation and transmission would be forced to adapt to a semi-intermittent source with a completely different cost structure. Genscape's active monitoring of power plants and transmission grids, as well as its intensive analysis of the interaction between weather patterns and power, will help to ensure that the market can respond rationally to these new pressures.