15 May 2010
Geoff Wilson
Director (Australia), World Green Infrastructure Network (WGIN)
President, Green Infrastructure Network Australia Inc.
Email: wilson.geoff@optusnet.com.au
Website: http://www.gina.org.au/
Solar cell power is poised for a rapid decline in costs and a rapid increase in electrical power harvest — to make it a most-likely mainstream power option in Australia in the next decade.
A major factor is cooling of solar cell panels by roof and wall greenery to produce about 10% more electrical power.
Optimum temperature for an operating solar cell is 25 degrees Celsius. For every degree above this there is a 0.5% reduction in electrical power output – and many ungreened Australian roofs can heat solar cells to around 60 to 70 degrees Celsius.
In Germany (which now uses about half the world’s solar panels for electricity generation) roof greenery cooling results in a 2% to 12% extra solar power harvest – with perhaps an average increase of around 5% in solar power supply.
In Australia the advantage on hot days is expected to be up to 25% (because of Australia’s better solar power climate). The average solar cell output should be increased by about 10% in cities like Brisbane.
During February 2010, seven Australian cities had special half-day lectures or discussions on how urban greenery can increase Australian solar power electricity yield.
Featured lecturer was Professor Manfred Kohler from Germany’s University of Applied Sciences in Neubrandenburg, where he founded the Green Roof Research Centre. He is also President of the 19-country World Green Infrastructure Network based in Toronto, Canada.
Professor Kohler was supported by University of Queensland student, Brian Chua, who, in his 2009 research and thesis showed that scientists of Queensland Department of Public Works were correct in 2006 about much better results from Australian greenery and solar power combinations.
Professor Kohler and Mr Chua described simple and well-proven rooftop greenery technology in combination with solar cells. Mr Chua is now collaborating with fellow members of the Green Infrastructure Network Australia Inc in a national program of practical demonstrations of the rooftop greenery-and-solar-power advantages.
Of likely great importance in the combination are advances being made by the Australian National University and by CSIRO in much-improved solar cells and reduction of solar power costs. ANU’s new technology is reported to offer 10 to 15 times the electricity production capacity of current solar cells. But the ANU solar power cells still suffer power loss if not cooled to around the 25 degrees Celsius optimum temperature.
Solar energy is the world’s most plentiful sustainabe energy resource. The challenge has been to tap into it with less cost and with greater efficiency – to reduce cost of electrical power supply. Three major trends will now accelerate the growth of world solar cell power:
- Urban rooftop greenery to cool solar panels for greater efficiency.
- Development of advanced solar power technologies (now happening in Australia as well as overseas).
- Likely emergence of China as a major, low-cost producer of solar power equipment.
Rooftop greenery advances are thus now offering Australia an opportunity to regain a good part of solar power leadership.
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