Solar, so good?

SAND AND SKY INITIATIVES FOCUS ON KEEPING THE HEAT IN

Solar and wind energy stored in 'sand batteries' could be used worldwide, whatever the season, and for months at a time, thanks to two young Finnish engineers Tommi Eronen and Markku Ylonen, founders of Polar Night Energy. Whilst there are a number of other research groups testing sand as a way of storing green energy, Tommi and Markku are the first to have successfully rigged theirs to a commercial power station (the Vatajankoski power plant which runs the district heating system) and the first to be storing thermal energy at extremely high temperatures.

The sand in their device stores the heat made from solar or wind electricity at around 500C which can then warm homes, offices and public buildings, especially in the winter when energy is more costly. Until now most batteries are made with lithium which has a large environmental footprint. They are also expensive and can't take in a huge amount of excess energy. The sand battery, on the other hand, is low-cost, low impact (the sand is from a local sandpit) and an effective medium for storing heat, losing only a little over time - they claim it can keep the sand at 500C for several months ...

NIGHT LIGHT

Meanwhile, University of New South Wales (UNSW) scientists say they've found a way to 'catch' solar energy that flows out of the earth at night. Still in its' early stages, they've managed to capture the infrared radiation before it escapes into space and convert it into electricity.

The amount of energy they've captured so far has been very small, but they hope that one day the technology could generate around 10% of the power produced by a solar powered cell ...