The dark side of solar energy

Imagine a field out in the middle of nowhere covered in a collection of heliostats, the solar panels that form a "farm" on which energy is harvested.

Like robotic sunflowers, they have little mirrors that turn throughout the day to catch the sun.

As the global fight against fossil fuels rages, these farms seem Utopian - until an image of water loss, birds crashing into panels and dust flying emerges.

For the first time, a group of local scientists has begun looking at the collective impact that could result when many such farms spring up in an area.

"We acknowledge the huge benefits of wind and solar power, but we also need to understand the new forms of impact they could have," said Professor Karen Esler, who supervised the research just published in the South African Journal of Science.

"Mainly of concern are habitat loss, water loss, dust and the impact on bird life. This is the first time anyone is considering what the impacts would be."

Lead researcher Justine Rudman, of the University of Stellenbosch, looked at solar power developments in two arid regions of South Africa - Nama-Karoo and Savanna - and interviewed experts.

"The footprints of those developments are relatively small but collectively the impact could be greater than we realise," Esler explained.

Birds, for example, suffer major collision impact when these artificial objects are placed in their environment.

The "visual dust impact" became apparent through previous projects, says Esler. The areas were cleared for the heliostats, but that resulted in more dust.

She said water loss was a problem in arid areas where concentrated solar power was being harnessed because it needed to be near a water source.