Why solar will leave coal for dead

– This is a copy of an article written by Rory McGuire and sent to the Sydney Morning Herald. Rory is a Sydney journalist who has been watching the solar energy market for 35 years.

If Scott Morrison had wanted to demonstrate his energy agnosticism when he waved a lump of coal around in Parliament he would also have waved a lump of silicon.

Assuming each weighed one kilo he could have explained that the coal, when burnt in a power station, would produce nearly 2.5 kilowatt-hours (kWh) of electricity, about 2.5 kilos of carbon dioxide, up to seven grams each of sulphur dioxide and various oxides of nitrogen, about 50 grams of fly ash, a few micrograms of heavy metals, including mercury, and some radioactive waste.

Then, holding up his piece of silicon, he could have said, “This could make a bit over two square metres of solar cells. As most of Australia gets at least five hours of full sun a day, which is about a thousand watts per square metre, this means the silicon, at 20 per cent efficiency, would generate in one day about as much electricity as my piece of coal.”

Then he could have told Parliament that the silicon cells were guaranteed for thirty years, during which they would generate over 20,000 kWh, or 10,000 times as much electricity as his piece of coal.

That was two and a half years ago. As was shown at Sydney’s Smart Energy Exhibition last April, some manufacturers have halved the thickness of their silicon and extended their warranties to 35 years. So a kilo of silicon can now generate well over 20,000 times more electricity than a kilo of coal.

And mainly because costs of PV energy have been reduced by 94 per cent since 2012, deployment is growing rapidly as the global energy industry sees the opportunities offered by cheap, relatively clean and virtually unlimited solar energy.

As one conference speaker said, “Two years ago we were talking about megawatt projects, which was huge. Now we are talking gigawatts.”

As has become more obvious during this election campaign, this growth has not been driven by any government initiative but by raw economics and popular demand as people become more alarmed by climate change.

Central to this growth has been intense collaboration between the  University of NSW team, led by Professor Martin Green and now with 600 students including 100 Ph.Ds, and R&D centres in Germany, the United States and China. This has stimulated massive production growth in China.

The Chinese expansion, especially since 2006, has been driven by industry acceptance of UNSW’s PERC technology (don’t ask!), because it allows cost savings and more efficient cells. But the market has seized on another advantage: bifacial cells, which absorb reflected light into the back of the cell, increasing overall performance. This offers new possibilities, such as in agriculture where rows of panels can be alternated with crops or livestock production. In six years PERC cells have come from nowhere to dominate the global market.

Australia is expected to add two gigawatts of rooftop solar this year. As 21 per cent of Australian homes already have rooftop solar it is obvious that we are thinking ahead of our governments. When we can make it on the roof for six cents a kWh, paying off a 30-year installation in about six years and with nearly free electricity after that, or pay our retailer 25 to 30 cents per kWh the choice is simple.

And the market has a long way to go. Professor Green told the conference the technology should allow us to produce electricity for one (US) cent a kWh in a decade or so. Given our reputation as early adopters he can expect a lot of customers.

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