San Diego’s Metropolitan Transit System (MTS) made a commitment to reduce greenhouse gas emissions, with its board unanimously approving a transition plan to convert all the agency’s 800 buses to zero emissions by 2040.

The transition plan will now be sent to the California Air Resources Board for certification. State regulations require public transit agencies to gradually transition to all-zero emission bus (ZEB) fleets by 2040.

“MTS has been testing six electric buses in revenue service over the past 10 months and we’ve been very pleased with their performance,” said Sharon Cooney, MTS CEO. “The performance data makes us confident that we can make a transition to an entire fleet of zero emissions buses over the next 19 years and continue to provide the highest quality of service our passengers expect and deserve.”

The ZEB transition plan approved by the MTS Board will serve as the agency’s blueprint to get all vehicles in the fleet to zero-emissions. Some key components of the plan include:

Emissions Reductions: Transition will cut the agency’s greenhouse gas emissions by approximately 43% over the next 19 years (this includes CO, VOC, NOx, PM 2.5, and PM 10).

25% Early Adoption: MTS will roll back the planned purchase of five CNG-powered buses in 2021 and purchase electric buses instead.

Cost: The full transition is estimated to cost $851 million over the next 19 years, and approximately $185 million to acquire land and build a new facility to accommodate additional electric buses needed to continue the current level of service.

Disadvantaged Community (DAC) Priority: MTS will prioritize zero-emission bus implementation in DACs, which often experience the most negative impacts of greenhouse gas emissions and environmental health.

Overhead Gantry System: The agency will build one of the first-in-the-nation overhead gantry system to automate charging, take advantage of off-peak and super-off-peak charging, and maximize space at its existing bus yards, which are already at capacity.

Electric and Hydrogen: The agency is planning to utilize a mix of battery-electric and hydrogen fuel-cell technologies to meet service range needs.

2028: The last year a CNG-powered bus will be purchased by MTS

MTS currently has six electric buses operating out of its divisions in downtown San Diego and East County. The agency will receive two more electric buses later this year. The electric buses have an average estimated usable range of 150 miles per charge. Many MTS bus routes are 150 miles or less, making them appropriate for this transition. Today, MTS’ 40- and 60-foot fixed route buses are fueled by CNG.