A number of U.S. cities including Los Angeles, New York, and Seattle have made commitments to transition their municipal bus fleets to 100% zero emission electric vehicles; Los Angeles by 2030; Seattle by 2030; New York City by 2040. And a number of other U.S. cities are considering a similar transition and acquiring electric buses for specific routes, and as trials to adjust to the technology. 

In China this transition is already well underway, and in 2017 the city of Shenzhen announced that it had completely electrified its fleet of 16,000 buses.  Reportedly in 2017 there were 385,000 electric buses in use, 99% of those in China. And electric buses are rapidly being adopted in Latin America.

Transportation is now determined to be the largest sector for carbon emissions in the U.S., and transitioning a city's bus fleet from fossil fuels to zero emission electric buses using renewable energy is a significant step that cities can make to address climate change.  

Houston Sierra Club has been advocating that Houston METRO begin to acquire some zero emission buses and to consider a transition of its bus fleet.

Houston METRO currently has a total bus fleet of 1,250 buses. Of these 1,200 are diesel, and 50 are CNG (natural gas).  Houston METRO did try out an electric bus for a 90 day pilot program in early 2017, but has not yet purchased any electric buses. The average lifespan of the current diesel buses is 12 years, so they are replaced at a rate of approximately 100 per year.  It would therefore take 12 plus years to replace the entire fleet.

In addition to reducing carbon emissions there would be significant environmental benefits if Houston METRO were to start replacing its diesel bus fleet with zero emission electric vehicles. There would be reduced particulate matter and other harmful diesel emissions, and noise reductions - all a benefit to neighborhoods, drivers, and passengers. Electric buses are initially more expensive, but more than recover that extra cost by reducing long term maintenance and fuel costs.
And as electric bus production ramps up, initial bus costs will decrease.  

Links to reports and source material:

Sierra article, The Future for Buses is Electric:
https://www.sierraclub.org/articles/2019/02/for-us-transit-agencies-future-for-buses-electric   

US PIRG Report, Ditching Diesel Isn't Just Good for Public Health and the Environment - It's Affordable:
https://uspirg.org/news/usp/ditching-diesel-isn%E2%80%99t-just-good-public-health-and-environment-it%E2%80%99s-affordable  

US PIRG Report, Electric Buses: Clean Transportation for Healthier Neighborhoods and Cleaner Air.
https://uspirg.org/reports/usp/electric-buses-clean-transportation-healthier-neighborhoods-and-cleaner-air

Sierra article, Los Angeles Accelerates Its Transition to Zero-Emission Buses:
https://www.sierraclub.org/compass/2017/11/los-angeles-accelerates-its-transition-zero-emission-buses

Chinese electric buses making biggest dent in worldwide oil demand:
https://electrek.co/2019/03/20/chinese-electric-buses-oil/

For questions, contact Frank Blake, frankblake@juno.com