The demonstration project is expected to cut the use of coal at the power plant by around two
or three percent, and could be scaled up to cut it by 10 percent. The system works through a
series of parabolic trough solar collectors made of glass mirrors. On sunny days the mirrors
concentrate the solar radiation onto a line of receiver tubes filled with a heat transfer fluid
(mineral oil). The solar energy heats the circulating oil to about 300°C (575°F). The heated
oil is then fed to a heat exchanger where the heat is transferred to water to heat it to around
200°C (407°F) before it enters the boiler. Having hotter water entering the boiler means less
coal is needed to heat it and produce the steam that turns the turbine to generate electricity.43