Monday 5 September 2011

Solar-thermal plants generate power day and night

Canberra Times
25 August 2011, Page: 16

The sun doesn't shine at night, the wind doesn't always blow. So John Coochey (Letters, August 17) jumps to the obvious, but wrong conclusion that these sources of energy can't provide baseload electricity. In Europe and the United States, large-scale, solar thermal plants generate baseload electricity 24 hours a day, every day. Mirrors focus energy from the sun on to a vessel containing salt.

The salt is heated to 600° Celsius during the day and the molten salt stores the heat through the night. This heat is used to produce steam, which drives conventional turbines to produce electricity. The Melbourne-based research group, Beyond Zero Emissions, shows in a report (www.beyondzeroemissions.org) how this technology could form the basis of a new electricity-generating system to meet Australia's future needs. BZE's plan includes wind and biomass, and could be broadened to use tidal and geothermal sources.

New generating stations and transmission lines are expensive. But the days of cheap electricity from fossil fuels are over. Oil is already in short supply. When costs and risks associated with climate change are factored in, renewables are the safe and sensible solution. Worldwide, new investment in electrical power generation from renewables now exceeds that from fossil fuels, according to United Nations figures. With abundant renewable energy sources, Australia has an unparalleled opportunity to invest in technically proven and commercially available options as the basis of our future energy security.

David Teather, Reid

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