Jeremy Cornford makes a valid point (TCW 25/3) but I would like to know where he got his figure of 1-1.5 per cent for the net efficiency of coal-fired power. From my research, even old single cycle power plants are about 33 per cent efficient. Efficiencies of over 45 per cent are now possible and over 55 per cent for combined cycle plants.[i] For modern cogeneration plants, where waste heat is utilised for industrial processes, an efficiency of 80 per cent is typical.[ii]
Photovoltaic solar panels, by comparison, are 15-20 per cent efficient (the range being 7.9 to 41.6 per cetn).[iii] Being black, they absorb nearly all solar radiation and dissipate as heat into the environment the 80-85 per cent that is not converted to electricity. A lot of carbon is used in their manufacture, so they have to operate at maximum efficiency for two to three years before they are carbon-neutral. And photovoltaic solar power still costs four times as much as coal-fired power. The price gap is slowly closing but has a long way to go.
Lest Jeremy think I am biased against solar, I should point out that I have solar panels (as well as a solar HWS) on our home, and shares in SILEX, the largest manufacturer of solar panels in the Southern Hemisphere. And my black panels probably cause more global warming than would the white roof they sit on. But what I find incongruous about the espoused ideology of the Labor governments that have been promoting solar power is that those unable to afford the technology now find themselves subsidising, via higher tariffs, those of us who could afford it.
I recently attended the public meeting on Beyond Zero Emissions and was impressed by their very ambitious and credible plan to decarbonise Australia by 2020, using wind and thermal solar with a bit of hydro and biomass back-up. But I wonder where we are going to find the $370 billion it will cost? That equals the NBN rollout cost every year for a decade. With our budget surplus long gone and our massive deficit mounting, we are almost guaranteed a heavy dependence on coal for many years to come.[i] Bugge, J. et al. 2006: High-efficiency coal-fired power plants development and perspectives. Energy. 31;1437-1445
[ii] Power station efficiency. Australian Institute of Energy. http://esvc000085.wic012u.server-web.com/melb/material/resource/pwr-eff.htm
[iii] http://en.wikipedia.org/wiki/File:PVeff(rev100414).png
Dr Wes Allen
Cudgen
