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| EXPLORE, ENJOY AND PROTECT THE PLANET | ||
| June/July 2006 | ||
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Transportation Sonoma Group | |
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One of the biggest sources of the greenhouse gas (GHG) emissions which are changing the earth's climate is gasoline-powered transportation. Sonoma County's 2005 Greenhouse Gas Inventory has estimated that transportation accounts for 42% of local GHG emissions from all sources, and approximately 60% of household emissions. Both conservation (driving less) and increased vehicle efficiency reduce GHG emissions from transportation. As individuals, we can change our driving habits by making fewer trips, using public transportation, and car-pooling. Bicycling and walking can replace car use close to home. Fuel efficient hybrid cars are already available, and more types of fuel-efficient vehicles will be coming onto the market soon. On a larger scale, we can redesign our communities to reduce car use, as Portland, Oregon has begun to do. The long-term strategy for completely eliminating GHG emissions from transportation is still unclear. It will require replacing gasoline with a fuel that doesn't produce GHGs either when it is manufactured or when it is consumed. Proposed alternative fuels generally fall into one of two categories: liquid biofuels, which could be used just like gasoline, or some kind of hydrogen fuel cell or electric battery. Biofuels are attractive because they could use the existing distribution infrastructure of gas stations - but they have significant drawbacks as well. While they produce about 25% of the GHGs that gasoline does, they are not zero emission fuels, and manufacturing and distributing them takes energy. The biggest problem however, is that they are made from plant material. If manufactured on the same scale that we use gasoline, biofuels could greatly increase the size of world agriculture. With growing turmoil on the horizon for global agriculture - from climate change, the increasing cost of energy and fertilizers, growth in world population and declining soil fertility - it doesn't make sense to invest in a big way in a technology that will put even more pressure on the finite amount of land we have. Fuel cells or batteries which are filled using fossil fuel-based technologies offer no advantage in the context of climate change. But there are lots of creative ideas around for different ways to fill a battery. Energy storage will be an important part of our future, since the most benign renewable energies, like solar or wind, are intermittent, and need to be stored to be reliable. Eventually we may be able to plug the electric car into our home windmill or let it recharge itself from its own solar collecting roof - but not quite yet. |
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