Collective impact of solar and wind power being studied in SA
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 on‚ these farms seem utopian — until an image of water loss‚ birds crashing into panels‚ and flying dust emerges.
For the first time‚ a group of local scientists has begun looking at the collective impact 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 collectively what the impacts would be."
Photovoltaic (PV) solar farms are already being built in the Karoo‚ and many more are planned.
Lead researcher Justine Rudman‚ from the University of Stellenbosch‚ looked at solar power developments in two arid regions of SA — Nama-Karoo‚ and Savanna — and interviewed experts about what the bigger picture could look like. Environmental impact assessments generally focus on the impact of an individual project.
"The footprints of those developments are relatively small but collectively‚ the impact could be greater than we realise. Just like with fracking‚ you can do an environmental impact assessment on different sites‚ but one also needs to stand back and look at the landscape as a whole‚" Esler explains.
Birds‚ for example‚ suffer major collision impact when these artificial objects are placed in their environment, with further research being done on this. The "visual dust impact" became apparent through previous projects‚ says Esler. The areas were cleared for the heliostats‚ but that resulted in more dust flying around.
"Now‚ it is felt that clearing is not considered a good idea. Leaving some cover helps with dust. We are learning by doing‚" says Esler.
Water loss is also a problem in arid areas where concentrated solar power (CSP) is being harnessed because it needs to be near a water source. Esler said the sum of the impact is greater than its individual parts‚ and there are "certainly benefits to solar but they must be weighed against the potential impacts".