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A Solar Grand Plan
Ken Zweibel, James Mason and Vasilis Fthenakis, Scientific American
By 2050 solar power could end U.S. dependence on foreign oil and slash greenhouse gas emissions
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In our plan, by 2050 photovoltaic technology would provide almost 3,000 gigawatts (GW), or billions of watts, of power. Some 30,000 square miles of photovoltaic arrays would have to be erected.
Although this area may sound enormous, installations already in place indicate that the land required for each gigawatt-hour of solar energy produced in the Southwest is less than that needed for a coal-powered plant when factoring in land for coal mining.
Studies by the National Renewable Energy Laboratory in Golden, Colo., show that more than enough land in the Southwest is available without requiring use of environmentally sensitive areas, population centers or difficult terrain. Jack Lavelle, a spokesperson for Arizona’s Department of Water Conservation, has noted that more than 80 percent of his state’s land is not privately owned and that Arizona is very interested in developing its solar potential. The benign nature of photovoltaic plants (including no water consumption) should keep environmental concerns to a minimum.
The main progress required, then, is to raise module efficiency to 14 percent. Although the efficiencies of commercial modules will never reach those of solar cells in the laboratory, cadmium telluride cells at the National Renewable Energy Laboratory are now up to 16.5 percent and rising. At least one manufacturer, First Solar in Perrysburg, Ohio, increased module efficiency from 6 to 10 percent from 2005 to 2007 and is reaching for 11.5 percent by 2010.
The great limiting factor of solar power, of course, is that it generates little electricity when skies are cloudy and none at night. Excess power must therefore be produced during sunny hours and stored for use during dark hours. Most energy storage systems such as batteries are expensive or inefficient.
Compressed-air energy storage has emerged as a successful alternative.
(January 2008)
Recommended by contributor Peter Salonius:
In case you have not read this month’s Scentific American article about Concentrating Solar Power(CSP) from Deserts — I hope you will become as enthused as I have by the promise of CSP combined with High Voltage Direct Current (HVDC) distribution grids (surrogate batteries) that greatly lower long distance transmission losses.
Ethanol fuel is not so green
Paul Syvret, The Courier-Mail, Brisbane
…It is something of a relief, therefore, to read a just-released parliamentary research paper on the economic effects of an ethanol mandate.
The paper concludes that “no prima facie economic case for a mandate has been established”.
In short, the findings of the report are as follows:
• Reduced oil imports are only one effect of an ethanol mandate on the trade account. Any diversion of feedstock (sugarcane, grains and the like) from exports, or increased imports of feedstock needed to meet the mandate would increase the trade deficit.
• A mandate is only one way of reducing reliance on imported oil. Importing ethanol, for example, would be less economically costly than a mandate, and would diversify geographic supply sources and the composition of fuel.
• The evidence suggests that the costs of creating jobs under an E10 mandate would be high. A mandate could also adversely affect other rural industries.
• The Biofuels Taskforce that the Howard government established concluded that greenhouse gas benefits alone would not warrant further assisting biofuels given the availability of much cheaper carbon reduction options.
• The additional demand for feedstock under a mandate might lead to competition for land from other uses (food, exports).
• A mandate could benefit the economy if domestic ethanol could compete with imports without government assistance.
Common sense at last.
(25 January 2008)
Contributor Stuart McCarthy writes:
A good piece from Paul Syvret, who broke the story on the McNamara Report in the Courier-Mail last year.
To bio or not to bio – are ‘green’ fuels really good for the earth?
David Adam, The Guardian
The EU says we need them, some experts say they damage the planet. Who is right?
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… But now a chill wind is blowing through this emerging industry. Fuels from vegetable oil, sugar, corn and a number of other crops and plants, collectively known as biofuels, are taking flak. There are doubts about their carbon savings, and concern over their impact on food supplies, prices and the land needed to grow them. This week, a parliamentary committee called for a moratorium on efforts to increase their use. Yet on Wednesday, the EU confirmed it will force oil companies to mix biofuel into petrol and diesel, while separate UK action on climate change will make all suppliers use biofuels by April.
It is a confusing situation, which provoked New Scientist to call on the UN’s Intergovernmental Panel on Climate Change to “determine whether biofuels are good or bad”. The issue splits even the green campaigners: Friends of the Earth said this week’s European move was a disaster; WWF welcomed it.
(26 January 2008)
