Renewables - Dec 3
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Many more articles are available through the Energy Bulletin homepage
The Implications of Biofuel Production for United States Water Supplies
Nate Hagens, The Oil Drum
In addressing the supply side of oil and gas depletion, much hope has been put into the scaling of 'biofuels', by applying new (and old) technologies to annual crops to create ethanol or biodiesel, thus providing chemically viable alternatives to the transportation liquids derived from crude oil.
Much of the biofuels debate thus far has focused on their lower energy balance, vis-a-vis crude oil. While this is important, analysis of the impacts on non-energy inputs and impacts should a massive scaling of biofuels occur, urgently needs to be discussed. The National Academy of Sciences recently published a report titled "Water Implications of Biofuel Production in the United States".
The paper outlines impacts and limitations on both water availability and water quality that would follow the pursuit of a national strategy to replace liquid fossil fuels with those made from biomass.
Some long time readers of theoildrum.com think we have beaten the corn ethanol horse to death. While this may appear true to certain camps (especially ethanol stock investors!), the fact remains that corn ethanol technology is still at the forefront of our nations mitigation responses to 'energy security' and Peak Oil.
Production is slated to increase from 5 billion gallons last year to 35 billion gallons in a decade. The DOE projects that biofuels can provide us with 30% of our liquid fuel needs by 2030.
However, given that we have limited amounts of high quality resources: crude oil, gasoline, fresh water, breathable air, healthy soil, productive ecosystems, etc., one of the highest policy priorities (in conjunction with attempts to change our conspicuous consumption paradigm) should be to establish the best use of these scarce resources to secure future energy flows.
Two of the most precious of these are energy and water, and are the subject of todays post.
(30 November 2007)
How Africa's desert sun can bring Europe power
Robin McKie, Observer
Europe is considering plans to spend more than £5bn on a string of giant solar power stations along the Mediterranean desert shores of northern Africa and the Middle East.
More than a hundred of the generators, each fitted with thousands of huge mirrors, would generate electricity to be transmitted by undersea cable to Europe and then distributed across the continent to European Union member nations, including Britain.
Billions of watts of power could be generated this way, enough to provide Europe with a sixth of its electricity needs and to allow it to make significant cuts in its carbon emissions. At the same time, the stations would be used as desalination plants to provide desert countries with desperately needed supplies of fresh water.
(2 December 2007)
Micro-wind turbines often increase CO2, says study
Robert Booth, The Guardian
It has become the home improvement of choice for the environmentally aware, but erecting a wind turbine on the side of your house could create more carbon dioxide than it actually saves, a study into their performance will reveal today.
David Cameron led the trend for "micro-wind" this year when he installed a turbine on the side of his west London home. But he may have been wasting his time and money. The Building Research Establishment Trust, which advises the government and private sector, has found that in built-up towns and cities weak winds and turbulence mean turbines are likely to add to, not subtract from, a home's carbon footprint.
The BRE took data from sites across Manchester, Lerwick and Portsmouth and analysed the likely performance of three models of turbine. In Manchester two-thirds of the 96 different options studied for siting turbines produced a carbon dioxide impact that could never be paid back. Building, installing and maintaining the units would, on balance, exacerbate global warming. The same was true in a third of cases in the coastal city of Portsmouth.
"Small windmills may work in the outskirts of Wick, but the current generation do not work well enough in built-up areas," said Martin Wyatt, the chief executive of the BRE Trust. "People need more information to ensure they are not doing the wrong thing."
After the energy used in manufacture from aluminium, steel, copper and fibreglass, the carbon footprint of the turbine is exacerbated by transportation to the site and the need for regular maintenance to moving parts which bear the strain of rapidly changing loads during heavy winds, the report found.
(30 November 2007)
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