July - September 2000

Costs of the Kyoto Protocol: A New Assessment
[Abstract]

Running Buses on Hydrogen Fuel Cells:
Barriers and Opportunities
[Abstract]

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Costs of the Kyoto Protocol: A New Assessment

n Energy Laboratory analysis suggests that enforcing the Kyoto Protocol may not be as expensive as most people think--as long as countries follow the intended guidelines. Most analyses consider the cost of reducing only carbon dioxide (CO2) emissions from fossil fuel use. But the protocol also recognizes reductions in other greenhouse gases (GHGs). According to the MIT analysis, taking advantage of opportunities to reduce those gases as well as CO2 can cut the cost of compliance in half. The protocol puts all gases on a common basis by using "global warming potentials" (GWPs) to weight the value of any emission reduction according to the gas's warming ability and lifetime in the atmosphere. In theory, then, meeting the Kyoto targets by cutting only CO2 or by cutting a combination of gases weighted using their GWPs should give the same climate impacts. To test the validity of the GWPs, the researchers used MIT's integrated atmospheric chemistry, climate, and ecosystem model to simulate the effects of the CO2-only and the multi-gas strategies for meeting the Kyoto requirements. The predicted global warming was similar for the two strategies. However, substantial differences appeared when the two strategies were used in response to a hypothetical policy involving deeper emissions cuts and participation by developing countries--assumptions that increase the role played by non-CO2 emissions. The GWPs are so flawed that such a stringent policy may or may not give the intended climate results, depending on which types of emissions are cut. The MIT team is now rethinking how to value emissions reductions, including considerations such as the timing of the avoided damage and the importance of protecting future generations from long-lived GHGs put into the atmosphere now.

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Running Buses on Hydrogen Fuel Cells:
Barriers and Opportunities

ehicles running on fuel cells fed by hydrogen could be ideal environmentally for crowded cities: they are quiet and clean, emitting none of the air pollutants that now plague urban areas. And emissions of greenhouse gases could be eliminated as well if the hydrogen were made using carbon-free sources such as solar power. But figuring out how to deliver hydrogen to private vehicles is a daunting problem, given today's fuel handling and storage technologies. Energy Laboratory researchers have looked at a more manageable application of this technology: in fleets of buses. They focused on a demonstration in which the Sunline Transit Agency in Los Angeles will gradually switch its buses from compressed natural gas engines to fuel cells, powered first by commercially provided liquid hydrogen and subsequently by compressed hydrogen gas that Sunline itself will manufacture from natural gas. This commercial experience will help clarify the issues involved in producing, handling, and storing hydrogen; maintaining and operating vehicles; and providing a given level of service. The MIT assessment identifies many of the practical hurdles Sunline must overcome, from setting up its hydrogen fueling station to retraining its managers and operators. Broader issues include the public's perception of hydrogen fuel as dangerous; potentially high costs; and still-evolving safety, zoning, and other regulations. Whether hydrogen will become the clean transportation fuel of the future remains to be seen. But if all goes as planned, Sunline's customers will get a first taste of the potential benefits of this technology: clean, quiet buses that get them where they need to go.

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Last updated: 02/2001

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