This one didn't get through the first time. Could be the Group's starts with an s and ends with an m box. I deleted some of the graphics in the hope that will fix it.
----- Original Message ----- From: Alvia Gaskill To: [email protected] Sent: Tuesday, December 02, 2008 2:59 AM Subject: Renewable Energy the Next Global Warming Source? Is the waste heat boogeyman lurking in the shadows? http://www.deadirect.co.uk/News/Micro-Generation/December-2008/Photovoltaic-panels-need-to-be-designed-to-reflect-less-heat?id=1336 Photovoltaic panels need to be designed to reflect less heat Category: Micro Generation (01.12.2008) Photovoltaic panels should be designed to minimise the amount of heat they reflect back into the atmosphere, according to scientists. Researchers have discovered that the amount of heat that dissipates into the environment could end up causing climate change even if carbon dioxide emissions are reduced to necessary levels. This is because the heat created in the generation and use of energy, while not currently a big concern, could become a trigger for climate change. Nick Cowern and Chihak Ahn of the School of Electrical, Electronic and Computer Engineering at Newcastle University claim that if energy consumption grows at one per cent a year – a slower rate than in recent history - by 2100 thermal emissions will begin to negate the benefits of reducing carbon emissions in line with current projections. They recommend geoengineering to combat the growing temperature as well as selecting low carbon energies carefully. Nuclear power, they say, should be avoided as it makes electricity out of energy that had been "locked away", creating waste heat. Instead they suggest using solar panels that use energy already in existence. However because solar panels reflect some heat which the earth would otherwise absorb, they recommend making photovoltaic panels that reflect less of the heat back into the atmosphere. http://www.newscientist.com/article/mg20026845.200-heat-we-emit-could-warm-the-earth.html Heat we emit could warm the Earth a.. 01 December 2008 by Mark Buchanan b.. Magazine issue 2684. Subscribe and get 4 free issues. c.. For similar stories, visit the Energy and Fuels and Climate Change Topic Guides This picture, taken with a thermal imaging camera, reveals how much heat is being emitted by City Hall in London (Image: National Pictures) EVEN if we turn to clean energy to reduce carbon emissions, the planet might carry on warming anyway due to the heat released into the environment by our ever-increasing consumption of energy. That's the contentious possibility raised by Nick Cowern and Chihak Ahn of the School of Electrical, Electronic and Computer Engineering at Newcastle University, UK. They argue that human energy consumption could begin to contribute significantly to global warming a century from now. Cowern and Ahn considered an emissions scenario proposed by James Hansen of the Goddard Institute for Space Studies in New York, and others. Under this scenario, which envisages greenhouse gases being cut significantly through phasing out coal over the next 40 years, Cowern and Ahn calculate that the greenhouse effect will start to diminish by 2050, stabilising the climate. But things may not go according to plan. The energy we generate and consume ultimately ends up being dissipated into the environment as heat. This input is relatively small today but might become significant in the next century, Cowern and Ahn suggest. Their calculations show that if global energy use increases at about 1 per cent per year - slower than in the recent past - then by 2100, the heat dissipated could become significant enough to cancel out the benefits of cuts in emissions (www.arxiv.org/abs/0811.0476). Being aware of this potential problem should inform what types of clean energy we adopt, say the pair. Nuclear power has the most harmful effect in that it releases energy that is otherwise locked up. Solar power is better as it exploits energy that the Earth is absorbing anyway, though Cowern and Ahn point out that solar cells tend to absorb more energy from the sun's rays than Earth's surface does, some of which ends up warming the local environment. One way round this could be to develop solar cells which absorb only the most energetic frequencies in the sun's rays. This could be done using "wide band gap" photovoltaic cells, containing layers that reflect low-frequency rays back. In the meantime, the cleanest energy options are wind and tidal power, say the researchers, as these tap into energy flows already present on Earth without significantly affecting them. Cowern and Ahn's argument is logical, says Jonathan Gregory, a climate expert at the University of Reading, UK. "Human energy dissipation is currently small compared with other factors, but you can imagine it becoming much bigger." However, he adds that energy production would need to grow significantly for the effect to kick in. "It's fair to ask if we could ever produce so much power," he says. Comments Greenhouse Effect Is The Cause Fri Nov 28 16:15:34 GMT 2008 by Vakibs The cause is the greenhouse effect, irrespective of the source of heat : sun or the heat emitted independently from earth. The heat emitted from earth (through nuclear power) does not increase the greenhouse effect. It just increases the amount of heat trapped inside. Assuming that there are no greenhouse gases (or that the quantity of these gases are very low), no heat ever gets trapped inside, irrespective of the source of the heat. Greenhouse gases can be explicitly removed (through olivine minerals, or Lackner process using nuclear power) in which case no amount of heat that we ever emit gets trapped inside. [The commenter is correct and if air capture can be made practical, then the lowering of ambient CO2 would offset the increase in waste heat retained in the atmosphere. Note also that Lackner has now become a process. AG] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
