Power in the desert  

The Guardian has progress report on the solar thermal power juggernaut in Spain - Power in the desert: solar towers will harness sunshine of southern Spain.

In the desert of southern Spain, 20 miles outside Seville, more than 1,000 mirrors are being carefully positioned. Each is about half the size of a tennis court, so the adjustments will take time. But when they are complete in a few weeks, it will mark a major moment in the quest for renewable energy.

The mirrors are part of the world's biggest solar tower plant, a technology that reflects sunlight to superheat water at a central tower. Once this €80m (£67m) plant is inaugurated in January, it will generate 20MW of electricity, enough to power 11,000 Spanish homes.

Concentrated solar power (CSP) technology, as it is known, is seen by many as a simpler, cheaper and more efficient way to harness the sun's energy than other methods such as photovoltaic (PV) panels. But CSP only works in places with clear skies and strong sunshine.

The Andalucian deserts are an ideal location, and Spain hopes the PS20 plant will enable it to take advantage of its huge solar resource and lead the field in CSP technology.

"The radiation hitting the earth is 10,000 times the consumption of energy," said José Domíngues Abascal, chief technology officer at Abengoa, the Spanish energy company behind the plant. "There is great potential in solar energy."

Abengoa has already built a smaller version of the tower technology to test that the idea works. The 11MW PS10 system has been generating electricity for almost two years. Its new design uses an area larger than 100 football pitches, with 1,255 mirrors, called heliostats, each with a collecting area of 120 sq m. These track the sun as it moves through the day and reflect the energy to the top of a 160-metre tower at the centre of the field. Here, the concentrated light is used to heat water to more than 1000C, producing steam that can turn an electricity generating turbine.

When switched on, the new plant will be the world's largest commercial CSP plant feeding electricity into a national grid. It will be also be a significant step for tower technology, seen as a candidate for the large-scale solar plants of the future.

Spanish firms are charging ahead with CSP: more than 50 solar projects around Spain have been approved for construction by the government and, by 2015, the country will generate more than 2GW of power from CSP, comfortably exceeding current national targets. The companies are also exporting their technology to Morocco, Algeria and the US.

"CSP is at the very beginning of a big boom," said José Luis García, at Greenpeace in Spain. "Spain is in a good position to develop and implement the technology. We have the sun so we are in the best position to lead in this field."

The country's clean energy targets are in line with the EU's plan to source 20% of primary energy from renewables by 2020, which means that 30% of electricity would have to come from carbon-free sources. A new EU renewables directive would increase that electricity target to 40%, but García said Spain could easily reach for more, up to 50%.