Climate and energy scenarios

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The reports from the Intergovernmental Panel on Climate Change (IPCC) in 2007 - as well as numerous other climate studies - are alarming. Climate change is taking place much faster than the scientific community expected only a few years ago. At the same time, the world's carbon dioxide emissions are still rising and in many countries the growth in emissions is accelerating. If we are to stop dangerous climate change, global emissions must peak no later than 2015 and be reduced by at least 50 per cent by 2050 (IPCC, 2007). However, the world is far from being on track for such a scenario. The message is clear: there is an urgent need to act now to speed the global energy revolution away from fossil fuels.

Alternative energy and emission scenarios aimed at phasing out nuclear and fossil energies have consistently put their emphasis on two pillars: massive expansion of energy efficiency and of renewable energies. Two recently released studies are from Greenpeace and the European Renewable Energy Council (EREC) (Greenpeace and EREC, 2007) and from the German government's Advisory Council on Global Change (WBGU, 2007). Their scenarios, projecting future energy, are based on the need to cut global greenhouse gas emissions consistent with the IPCC findings. They also assume the same global primary energy consumption as today, with 50 per cent coming from energies produced from fossil fuels. Such a scenario would have only a slim chance of keeping the global average temperature rise below 2°C. Both scenarios call for a massive energy-efficiency revolution and a massive increase in renewable energy. The Greenpeace/EREC scenario sees a tenfold increase of global bioenergy use for electricity production by 2050, 60 per cent coming from energy crops. The WBGU study calls for an increase in bioenergy for electricity production from 1.5 per cent globally to 30 per cent by 2025, and wind from 1 to 20 per cent by 2025.

The question now is: what is the most efficient use for bioenergy? No other renewable energy source can be used in such manifold ways. A key question here is the 'greenhouse gas emissions balance' - carbon dioxide released from its combustion must be 'captured' by plants grown in the next productive cycle. This is not always necessarily the case. Bioenergy sources generated by a massive input of fossil fuel sources (fertilizers, processing, transport, etc.) can have a greenhouse gas emissions balance that is hardly any better than fossil fuels. The sustainability of an energy source can, in the end, only be determined by a life-cycle assessment of the entire production and utilization chain of each energy source.

As soon as climate protection (meaning the reduction of fossil fuel combustion) is recognized as a key driver for the utilization of bioenergy, priority must then be given to those forms of biomass that reduce the largest amounts of carbon dioxide emissions and are the most energy efficient. Processed into liquid fuels, bioenergy as indicated in life-cycle assessments is five to ten times less energy efficient than biogas, wood or woody biomass.

In the immediate future this means that, in most countries, the use of biomass in the electricity and heating sector will achieve the highest greenhouse gas emissions substitution potential by replacing coal, the most greenhouse gas-intensive fossil fuel. In the electricity and heat sector, agricultural residues and biomass waste, as well as unprocessed biomass from the forestry and agricultural sectors, are the inputs that are most suitable. Biomass, in contrast to the intermittently available renewable energy sources such as wind and sun, is available at all times. In combination with wind and sun, biomass can be crucial to maximize the potential of all three renewable energy sources as a standard base load energy source.

However, greenhouse gas reduction is only one driver for biofuels. Energy security, the dependence upon imported petroleum with all its economic and political problems, is a second powerful driver for biofuels, often overriding climate concerns. The transport sector of any modern economy is strongly dependent upon petroleum. Therefore, the petroleum and automobile industries put particular emphasis on using biomass for the production of liquid fuels. However, due to processing and refining, the use of biomass results in greater reductions in carbon dioxide emissions. Clearly, the development of sustainable energy policies also has to address the transport sector.

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Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

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