Here’s a case of strange bedfellows: the world’s first hybrid coal-solar power plant is now up and running outside Palisade, Colorado. A joint project between the utilities giant Xcel Energy and Abengoa Solar, the unit of Xcel’s Cameo plant is intended to show that solar power can reduce the environmental impact of coal-fired power plants.
The plant uses parabolic trough solar collectors to heat the water that goes into the coal-fired turbine, which will reduce the amount of coal used at the facility by 2 to 3 percent. For a cost of $4.5 million, the hybrid plant will produce the equivalent of just one of 49 megawatts from solar power.
It hardly sounds like a bargain to this blogger, but it’s part of the coal industry’s aggressive efforts to keep its irons in the fire as pressure mounts for cleaner energy alternatives. Indeed, several utilities have joined with the Electric Power Research Institute to study the hybrid coal-solar combination in North Carolina and New Mexico, and a solar-natural gas plant is already under construction in the Sunshine State.
Abengoa has pioneered the parabolic trough solar collector, in which glass mirrors which concentrate the sun’s energy into a series of tubes filled with a heat transfer fluid — in this case, mineral oil. When the oil reaches 300°C, it is fed to an exchanger where the heat is transferred to water, bringing it nearly to boiling before it enters the boiler where a coal fire will convert it to steam, driving the turbine that generates electricity.