Student designs solar system for night time power

Claus Volkening has designed the first working, small-scale model of a solar updraft tower, which uses water storage tanks to solve the problem of existing solar power plants that only generate electricity when the sun shines.

The water storage tanks store some of the heat generated throughout the day, Volkening said: “After sunset, the updraft drops and the energy output effectively stops. In my model, some of the solar energy is removed from the air flow process to heat the water and this is then released at night. This avoids a peak during the day and smooths the overall output.”

The scale model is based on a one kilometre high tower surrounded by glass or plastic above water tanks across a 16 kilometre square area to recreate a greenhouse effect. It would generate 100 megawatts of electricity, enough to keep 80,000 British households supplied.

“An easy and cheap way to store green energy is desperately needed as the world increasingly demands renewable energy," said Volkening. "But the problem with existing solar power generators is that the times of peak generation of energy during the day, do not match with times of peak need at night. I wanted to find a way of generating solar power at night and found that by using water tanks to store the sun’s energy through the day I could smooth out the energy available from a solar power plant. With my model even when night falls and temperatures drop electricity is still available and reliable."

Volkening says more work needs to be done on his invention, including an investigation of other materials to be used as storage elements before it could be used as a blueprint for solar updraft tower plants around the world.

Volkening’s tutor at Portsmouth, Dr James Buick said: “The technology behind solar updraft tower power plants is simple and they can be made from materials available anywhere in the world, which means, unlike other technologies, they are suitable for less developed countries.”