Study finds electric buses operating are cleaner on well-to-wheel GHG basis all over US
Tue 14 August 2018
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A new study by the Union of Concerned Scientists finds that electric buses operating in all areas of the United States (i.e. under widely varying electricity grid mix) produce lower emissions of greenhouse gases (GHG) than the diesel or natural gas buses that they replace.
Where the electricity grid is already more decarbonised - such as in California - electric buses are more than three times better than diesel buses operating there.
Battery electric buses range from 1.4 to 7.7 times better than a diesel bus, as shown in miles per gallon emissions-equivalency in the accompanying chart ie a diesel bus has nearly 1½ to 8 times the global warming emissions of an electric bus, depending on the region.
The researchers point out that the US powergrid (in common with electricity production in the UK and most other countries in the world) is getting cleaner every year. Emission rates from electricity have steadily declined over the last sixteen years. Transport agencies can also choose cleaner power than what’s provided on their grids by installing solar panels and batteries on site or through renewable electricity contracts.
Charged with the national electricity mix, a battery electric bus has global warming emissions equivalent to a diesel bus getting 12 miles per gallon. This is 2.5 times better than an actual diesel bus (4.8 miles per gallon).
Overall, the study found that, on average, electric buses produce less than half of the GHG emissions of diesel or natural gas buses.
Electric buses are cleanest in places with relatively high levels of low-carbon power, such as the Pacific Northwest, California and the Northeast.
Dr. Jimmy O’Dea, Senior Vehicles Analyst at UCS (quoted by Charged EVs) said: “In regions that use a lot of renewable energy, transitioning to electric buses should be a no-brainer. But even in places like Cleveland or Minneapolis that still rely on coal, electric buses have the advantage of getting cleaner as the power grid gets cleaner, and transit agencies have the option to power their buses with renewable electricity.”
Note: In other US news, California has set a goal of achieving 100 percent clean energy by 2045. Under legislation passed by the State Assembly, California utilities will also be required to get half their energy from wind, solar and other specific renewable sources by 2026 — four years sooner than current law requires. By 2030, the target is 60% renewably sourced electricity to 100% by 2045. (See link.)
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