AN ELECTRICITY generating station in southern Spain powered by heat from the sun is signalling a new dawn for an almost forgotten source of renewable energy. Trials on a prototype solar thermal power plant in the desert landscape of Almer'a have shown it to be cheaper, more efficient and able to operate on a bigger scale than rival photovoltaic technology.
Solar thermal energy was briefly fashionable after the oil price shocks of the 1970s. But the fashion waned when photovoltaic (PV) cells, initially developed for space travel, came into favour for what visionaries foresaw as the "solar century" ahead.
But a few died-in-the-wool solar thermal power advocates refused to give up, and they now believe their time has come. Only thermal power can concentrate solar energy sufficiently to generate electricity on the scale of commercial power stations, they say.
The technology owes its change of fortunes to a combination of ...
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