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February 19, 2008
Sustainability Roundup: Honda Hybrid & Biofuel Emissions
Honda Introduces Breakthrough Hybrid Engine
The Toyota Prius is widely regarded as the standard hybrid vehicle in the US. Nevertheless, the efficiency gains are limited to driving at speeds less than 65 miles per hour (100 km per hour).
Hybrids vehicles typically have higher mileage (fuel efficiency) on local streets than they do on fast highways. That's because they capture energy using regenerative braking, which converts the motion of the car into electricity that is stored in the batteries.
Honda has announced a new type of hybrid engine that converts heat coming out of the exhaust into work. In doing so, the system is able to capture three times as much energy as regenerative braking. The system will work for both local and highway driving, improving overall energy efficiency of the vehicle.
For more on this advanced design, see this detailed article at Green Car Congress.
Research: Biofuels Lead to Increased Greenhouse Gas Emissions
In the US, certain agricultural and transportation interests have claimed environmental benefits of producing biofuels from corn but in a recent paper in Science Magazine, Tim Searchinger claims that not only does corn-based fuel offer no environmental benefits, carbon dioxide emissions are greatly increased over petroleum.
Unliked earlier studies, Searchinger's paper attempts to quantify the impact of land use changes associated with growing crops. By creating land for corn that were originally carbon sinks or forests growing in carbon capture, large amounts of greenhouse gases are released in the process.
Searchinger estimates that the overall emissions from corn biofuel is up to twice that of conventional gasoline.
投稿者 econetworks : February 19, 2008 08:11 AM
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