Power Tower Reflects Well on Sunny Spain

Europe has gained a new source of renewable energy with the inauguration of the continent's first-ever "power tower" at the centre of a field of mirrors near the southern Spanish town of Sanlúcar la Mayor.

The 115-metre-high tower (377ft) is the key element in what is being hailed as the world's first-ever commercial power tower plant. Rings of huge mirrors laid out around it reflect and focus the sun's power, beaming it back up to the top of the tower where the intense heat is absorbed and transmitted to a steam-driven generator.

A total of 624 large mirrors have been placed around the tower to harvest the intense sunshine of south-western Spain.

The 120 sq m heliostat mirrors automatically track the sun as it moves east to west. They will produce temperatures of up to 250C (482F). The tower will produce 11MW of electricity, enough to power some 6,000 homes. "It will save 18,000 tonnes of carbon emissions every year," a spokesman for Arbengoa, the company behind the power tower, said .

The tower, known simply as PS10, represents a comeback for this form of solar energy, which was first tested in the Mojave desert of California in the 1980s.

It is the first stage of an ambitious solar power project at the Sanlúcar la Mayor site, which will use various kinds of solar technology to produce some 300MW of energy within six years. That will be enough to light up some 180,000 homes.

The project includes a second power tower, the PS20, which is due to produce almost twice as much energy as the first.

The power tower in the Mojave became well known when it featured in films such as Wim Wenders' Bagdad Cafe, but other forms of solar energy gained favour in the 1990s.

Solar panels, especially, have been the main focus of research in recent years but improvements in the technology behind the heliostat mirrors has brought renewed interest. Other mirror-based systems, known as concentrating solar power systems, direct the sun's rays onto tubes of liquid or on to a central collecting point in a dish-shaped mirror.

A 64MW solar concentrating power plant, which does not use a tower, is due to open in the Eldorado valley of the Nevada desert later this month, while Israel, Egypt, France, Australia and Algeria are all studying ways to build concentrating solar power system plants. South Africa is considering a 100MW power tower with 5,000 mirrors in the northern Cape.

It still costs around twice as much to produce electricity via concentrating solar power as it does from fossil fuels.