Sun worshippers

A Spanish solar thermal plant, PS20, has brought fresh proof of the efficacy of solar thermal power.

Abengoa Solar operates the new plant, which has a power capacity of 20 megawatts, enough juice to power about 10,000 homes. The plant uses 1,255 heliostats (motorized mirrors) to reflect sunshine onto a fixed focal point. The heliostats follow the sun’s path throughout the day to catch maximum rays.

With a surface area of 1,291 square feet each, the massive mirrors working together focus over a million and a half effective square feet of sunlight on the apex of the tower. That heat energy can be used to boil steam to turn turbines, or stored for later use.

Concentrating solar power (CSP) has also provided the answer for solar storage. Electrical batteries while affording an option for small units are expensive, and impractical for utility-scale power storage. In CSP, as it is the heat that is being used instead of light, the heated water or fluid can be stored in insulated tanks and used when required.

Current technology can store solar-generated heat for up to 7-12 hours.

Solar thermal not only can provide for stand-alone generation but can work with fossil-based plants by providing the heat and reduce the need for coal and help reduce emissions.

The potential for places in the tropics where the sun burns down powerfully cannot be over-emphasised. The land required, of course, is on a slightly large scale but technology is developing that is already showing optimum designing of the mirrors to cut space requirement by half.

If you have any experiential insights on this technology, let us know.