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Zero Emission Buses

Zero Emission Buses

The Future of Transit
AC Transit’s Zero Emission Bus Fleet

AC Transit announces the release of the second version of our Zero Emission Transit Bus Technology Analysis (ZETBTA) study. Our current report tracks greenhouse gas emissions, cost per mile, fleet availability and other intelligent data spanning January through June 2021.

The ZETBTA study’s data is reliable because it is captured from a control fleet using the same 25 buses, then reinforced through academic evaluation by scientists at Stanford University’s Precourt Institute for Energy.

The study’s results will permit AC Transit to determine the ideal zero emission bus technology for the East Bay, and will also provide a zero emission conversion roadmap for transit agencies worldwide in:

  • Planning 
  • Procurement 
  • Workforce Development & Training 
  • Guides to curtailing costly missteps toward zero emissions conversions
Battery electric bus

Our open-source study has evolved into transit industry’s #RoadMapTo2040. Read the most recent report here.

The ZETBTA is a robust side-by-side evaluation of the predominant bus technologies in use at transit agencies worldwide: fuel cell electric bus (FCEB), battery electric bus (BEB), diesel hybrid, and conventional diesel bus propulsion systems.

The initial version of our groundbreaking study was released in July 2021. Our testing data sets are forecasted for public release every six months. 

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Zero Emission Buses

History of Leadership

AC Transit has a proud history of embracing environmental technology in our efforts to better serve our neighborhoods and has long been a recognized leader in this field, both nationally and internationally. Our first hydrogen fueling facility was opened in November of 2002 at our Richmond Division to operate a single 30-foot fuel cell electric bus. In 2006, we launched our first-generation fuel cell electric bus pilot program, operating three vehicles and a station out of our East Oakland Division. In 2010, we added 13 second-generation fuel cell electric buses to the fleet and opened a second hydrogen fueling station at our Emeryville Division. A solid oxide stationary fuel cell was added to our East Oakland Division in 2013. Then, the following year, we opened a new hydrogen fueling station on the site. In 2017, our fuel cell power plants surpassed the Department of Energy and Federal Transit Administration’s target numbers of 25,000 hours of operation.

Then in 2019, AC Transit embarked on a true side-by-side comparison—incorporating five battery electric buses and seven charging stations into our expanding fleet of ZEBs. We will be running hydrogen and battery electric vehicles in identical service to collect real-world performance data for comparison—and to determine which technology performs better to meet the needs of our service as we move towards a complete zero-emission fleet by 2040.

Flowers in a field

2040 Zero Emission Goal

AC Transit has embraced the exhaust emission standards set by the California Air Resources Board (CARB) for more than 18 years. Since its implementation, our transit district has adopted operational practices and programs that proudly exceed state environmental standards—including building one of the most comprehensive hydrogen fuel cell programs in the United States. As funding allows, AC Transit continues to purchase and integrate new ZEBs into our fleet—prioritizing their deployment to several disadvantaged communities through our Clean Corridors Plan. In 2019, AC Transit became the first public transit operator to conduct a side-by-side analysis of buses using fuel cell versus battery electric technologies to determine which works best for our service.

ZEB cityscape high resolution


The majority of funding used for AC Transit’s environmental programs has come from generous grants provided by agencies including the California Air Resources Board and Federal Transit Administration. This money has been earmarked for specific use and cannot be utilized for any other purpose. And, thanks to Senate Bill 1, AC Transit has secured the funding to purchase an additional 45 zero emission buses. 40 of these new ZEBs will replace old diesel vehicles and will be funded by over a half dozen sources. We consider ourselves fortunate to be the recipients of grant and state funding that allows us to explore cleaner modes of public transit that will improve the environment in the district we serve.