Lew Fulton

Disappointed by Diesel? Impact of Shift to Diesels in Europe Through 2006

A previous review of the trends in the sales and use of light-duty diesel-powered vehicles (diesel vehicles) in Europe through the mid-1990s questioned whether the shift toward diesel vehicles would yield large energy savings. The present study expands on the previous review. Although evidence still exists that diesel vehicles of a certain size have a substantial volumetric fuel economy advantage over gasoline-powered vehicles (gasoline vehicles) of a similar size (perhaps 30%, on average), average new diesel cars (including sport utility vehicles, personal vans, personal light trucks) and the stock of diesel vehicles on the road maintain a smaller efficiency advantage over gasoline vehicles, which, as of 2005, was on the order of 15% in most countries. When the higher energy content of diesel is considered, the fuel intensity advantages for new vehicles and vehicles already on the road shrink to less than 5% and 7% for new diesel vehicles and the stock of diesel vehicles, respectively. For new diesel vehicles, the net difference in the amount of carbon dioxide (CO2) released per kilometer (the CO2 advantage) is even less: for new cars, less than 5% in all but one country and 0%, on average, across the eight countries sampled in 2005. For the total stock of diesel vehicles on the road, diesel vehicles provide only a small reduction in emissions compared with those of gasoline vehicles. Even with normalization for the larger average size of diesel vehicles, their CO2 advantage appears to be no more than 15% to 18% for cars of a similar size class. The findings indicate that after all factors are taken into account, diesel vehicles in Europe may provide significant fuel savings to individual drivers but probably do not provide significant national energy or CO2 savings, on average, among the eight countries studied.

Making Urban Transit Systems Sustainable Around the World: Many Birds with One Bus?

Urban transport in most cities around the world is developing in an unsustainable fashion, as reflected by rapid growth in traffic congestion and air pollution driven by individual motorization. Strengthened bus systems, built on rapid bus corridors, and improved bus technologies could play an important role in putting cities on a more sustainable path. Results and some of the main messages are presented from a recent study at the International Energy Agency, Paris, which has assessed the situation in a number of the largest cities in the developing world, while also drawing on experience from several cities in the developed world. A principal finding is that buses tend to carry a large share of travelers but contribute only a small part of total traffic and pollution. Also, although bus ridership is declining in many cities, new types of bus systems are emerging that offer the potential to reverse these trends and have done so in several cities (e.g., Curitiba, Brazil, and Bogota, Columbia). Advanced bus propulsion systems, that is, fuel cell and hybrid buses running on a variety of fuels, could eventually provide substantial relief from busrelated pollution problems. However, in developing countries, spending scarce funds for cleaning up the emissions from present technologies, along with developing improved bus systems that enhance traffic flow, would provide far more relief in the near-term than spending on a few advanced technology buses. Both paths must be followed, but the latter must not obscure the former. Conditions necessary for bus systems to prosper are discussed and, in conclusion, recent promising developments are highlighted.

The Importance of Passenger Cars for Global Greenhouse Gas Emissions – Today and Tomorrow

Worldwide energy use and CO2 emissions are on a trajectory to double by 2050. Transport is on a similar trajectory. The stock of light duty vehicles could triple. This paper explores scenarios to cut the energy and CO2 emissions of light-duty vehicles. It is found that deep reductions will require both the widespread adoption of current best available technology, e.g. via measures to maximize their use to improve fuel economy, and the longer-term development and deployment of a range of new technologies such as electric and plug-in hybrid vehicles. A combination of doubling fuel economy (halving fuel intensity) from 2005 levels and strong rates of adoption of new technology vehicles and fuels (e.g. electric and plug-in hybrid vehicles accounting for more than half the vehicles on the road by 2050) could cut oil use and CO2 emissions by well more than half in 2050, compared to Baseline 2050 levels (and to half of 2005 levels in Europe). However, the changes needed will be dramatic including unprecedented penetration rates for certain key technologies. At the same time, some other trends must stop: those toward ever larger, more powerful cars, and trends in some countries toward ever-greater dependence on the car for all types of trips. And while the emergence of low cost cars can provide mobility to millions of people, society must ask if this is the best way to provide such mobility, rather than (for example) via advanced bus and train systems, and with land use patterns supporting a bigger role for non-motorized transport.