Stored solar power in Spain -- at huge expense
Part of the reason Spain's Greenie schemes sent their government broke -- and caused it to renege on many of their subsidy promises. Just the first stage (there have been 3 stages) of the plant cost around €300 million (US$380 million) to build and it has big maintenance costs as well. Even after the big initial cost it still requires a subsidy to keep it going. And it uses up vast amounts of water for cooling -- which is not good in a desert region, where most such plants are located
On a barren, sun-baked plateau in southern Spain, row upon row of gleaming mirrors form one of the world's biggest solar power plants and harness the sun's power - even after dark.
The Andasol plant near Granada, provides electricity for up to about 500,000 people using about 620,000 curved mirrors.
While it’s not the world’s largest solar farm, it is incredibly powerful, with the mirrors tracking the sun as the Earth turns, to harness as much solar power as possible.
It gets round the main drawback for solar power – that the sun does not always shine – by storing energy to drive turbines after sundown, making it very different to rooftop solar panels, which sunlight directly into electricity.
The main sound at the site, near the town of Guadix, is a whirring of motors to swivel the huge mirrors mounted on giant steel frames, Reuters reported.
The glass alone would cover 0.6 square miles (1.5 square km) which is the size of about 210 football pitches.
The plant, named after the local region of Andalucía and ‘sol’, meaning sun, can generate around 150 megawatts of electricity, making it among the world's largest.
But in comparison, Ivanpah Solar Power Facility in San Bernadino County, Caifornia, is over twice as large as Andasol in terms of capacity and is able to generate 392 megawatts of electricity.
Like Ivanpah, the Andasol plant uses parabolic troughs, which are a type of solar thermal collector that is straight in one dimension and curved as a parabola in the other two, lined with a polished metal mirror.
Sunlight bounces off the mirrors to heat a synthetic oil in a tube to a blazing 400°C (752°F).
That energy is in turn used to drive a turbine, generating electricity.
At Andasol, some energy also goes into two heat reservoirs, which are tanks containing thousands of tonnes of molten salt that can drive the turbines after sundown, or when it is overcast, for about seven-and-a-half hours.
This process almost doubles the number of operational hours at the solar thermal power plant per year.
There is little sign of life at the semi-desert site of Andasol, which lies at an altitude of 3,600 feet (1,100 metres) near the snow-capped Sierra Nevada range.
Some hardy red and yellow flowers grow around the fringes, a few pigeons flap past and workers say that the odd fox lopes by at night.
The environmental benefits of clean energy are judged to outweigh the scar to the landscape from the mirrors, which are visible from space.
The land is infertile, there is little wildlife and few people live nearby. The biggest regional city, Granada, with about 240,000 people, is 70 km (45 miles) away.
Posted by John J. Ray (M.A.; Ph.D.).