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Earth, Wind & Fire
Jonathan Holmes, ABC Australia
Picture a windswept hillside lined with slender white skyscrapers, each crowned by a giant whirring rotor longer than a jumbo jet. Or a swathe of desert covered by a sea of mirrors drawing power from the sun.
Wind and solar projects are already in place, or planned, on a much grander scale overseas than here. For decades coal-rich Australia has regarded renewable energy as virtuous, but incapable of meeting the needs of a modern economy. It’s been too costly, not yet proven, intermittent, at best a help at the margins.
Jonathan Holmes looks to the future – California – to gauge the challenge that faces Australia. Republican Governor Arnold Schwarzenegger has joined hands with Democrat legislators to set some of the world’s most ambitious targets for cutting greenhouse emissions and boosting renewable energy. In just three years 20 per cent of California’s power will have to come from renewable energy. There’s serious consideration to making that target 33 per cent by 2020.
Australian entrepreneurs are flocking to the Californian action. A Sydney based company is financing a wind farm there that will produce twice as much power as all Australia’s wind farms put together. An Australian solar thermal technologist has scored the backing of futurist Vinod Khosla, founder of Sun Microsystems. “It’s cheap,” explains Khosla to Four Corners, when asked what he likes about the technology. Khosla expects to make money and help the climate too.
Can Australia, whose coal-fired power stations currently produce power at half the price of Californian electricity, provide enough incentive to attract investment to ambitious solar and geothermal schemes that are still in their infancy? Is Australia in danger of getting left behind? Khosla says “most industrial advantage in the world comes through innovation. And if you stick with coal, you won’t have that.”
(16 Apr 2007)
Program and extended interviews with Vinod Khosla, Adrian Williams of Geodynamics and Federal Minister Ian Macfarlane available as video on demand, program transcript here.
Solar energy conversion
George W. Crabtree and Nathan S. Lewis, Physics Today
If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience.
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Despite the abundance and versatility of solar energy, we use very little of it to directly power human activities. Solar electricity accounts for a minuscule 0.015% of world electricity production, and solar heat for 0.3% of global heating of space and water. Biomass produced by natural photosynthesis is by far the largest use of solar energy; its combustion or gasification accounts for about 11% of human energy needs. However, more than two-thirds of that is gathered unsustainably-that is, with no replacement plan-and burned in small, inefficient stoves where combustion is incomplete and the resulting pollutants are uncontrolled.
Between 80% and 85% of our energy comes from fossil fuels, a product of ancient biomass stored beneath Earth’s surface for up to 200 million years. Fossil-fuel resources are of finite extent and are distributed unevenly beneath Earth’s surface. When fossil fuels are turned into useful energy though combustion, they produce greenhouse gases and other harmful environmental pollutants. In contrast, solar photons are effectively inexhaustible and unrestricted by geopolitical boundaries. Their direct use for energy production does not threaten health or climate. The solar resource’s magnitude, wide availability, versatility, and benign effect on the environment and climate make it an appealing energy source.
Raising efficiency
The enormous gap between the potential of solar energy and our use of it is due to cost and conversion capacity. Fossil fuels meet our energy demands much more cheaply than solar alternatives, in part because fossil-fuel deposits are concentrated sources of energy, whereas the Sun distributes photons fairly uniformly over Earth at a more modest energy density. The use of biomass as fuel is limited by the production capacity of the available land and water. The cost and capacity limitations on solar energy use are most effectively addressed by a single research objective: cost effectively raising conversion efficiency.
The best commercial solar cells based on single-crystal silicon are about 18% efficient. Laboratory solar cells based on cheaper dye sensitization of oxide semiconductors are typically less than 10% efficient, and those based on even cheaper organic materials are 2-5% efficient. Green plants convert sunlight into biomass with a typical yearly averaged efficiency of less than 0.3%.
George Crabtree is a senior scientist at Argonne National Laboratory in Argonne, Illinois, and director of its materials science division. Nathan Lewis is a professor of chemistry at the California Institute of Technology in Pasadena, California, and director of the molecular materials research center at Caltech’s Beckman Institute.
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(March 2007)
Also available is a PDF version.
Hat tip to Curt P.
Renewable sources of energy branded a ‘crime’
Barry Fitzgerald, The Age
THE visiting director of Rockefeller University’s human environment program, Jesse Ausubel, believes renewable sources of energy are “environmentally criminal”.
Mr Ausubel got no argument on that score from the 1500 delegates at APPEA’s [Australian Petroleum Production & Exploration Association] annual oil and gas conference in Adelaide yesterday. He said he was not a climate change sceptic as “global warming is under way”.
But renewables were not the answer. Phasing out the coal industry over the next 20 to 30 years, increasing gas consumption and an eventual wholesale move into nuclear power is Mr Ausubel’s answer.
He said he wanted to see land being used for bears, tigers and kangaroos rather than devoted to huge wind and solar farms and intense biomass creation. ..
He also warned that the main beneficiaries from carbon trading schemes would be lawyers, accountants, financial intermediaries and administrators. ..
(17 Apr 2007)
A disingenuous argument against renewables: population growth, timber demand, non-energy agriculture and now climate change are far more significant threats to remaining wildlife.-LJ
