The Zero Emission Choice: Battery or hydrogen powered transit

Replacing diesel vehicles with cleaner options is a critical component in advancing net zero goals. For passenger vehicles, it is clear the future lies with electric vehicles — with on-board batteries charged via the grid. But for larger vehicles with higher daily energy needs, the limitations of current batteries — in terms of capacity, size and weight — become even more important. Fuel cell engines powered by hydrogen can overcome some of these limitations but introduce other challenges.

In the transit market, battery buses gained an early lead over the past 10 years with almost 6,000 vehicles in service, or on order, and less than 400 hydrogen buses in service. But that may be changing. Interest in hydrogen as a zero-emission option has significantly increased over the past two years, as evidenced by increased funding for hydrogen buses and infrastructure under Federal Transit Administration’s Low/No grant program.

As agencies face challenges around battery electric bus availability, performance and technology integration, should they be giving hydrogen a second look? Both technologies store energy on board to run an electric motor that powers the bus down the road. Fuel cells work like batteries, but they do not need recharging from the grid. They can produce electricity continuously as long as hydrogen fuel is supplied. This hydrogen fuel is stored on the vehicle as a high-pressure gas — similar to the way compressed natural gas buses store their fuel, but at even higher pressure.

At present, both battery electric and hydrogen fuel cell buses are significantly more expensive to buy than their diesel or clean natural gas counterparts, with fuel cell buses being the costliest. Both also require significant investments in new depot infrastructure, but the capital costs for hydrogen fueling and storage buildout can be lower than for battery electric charging infrastructure, especially at larger scale.

Fuel cell buses have a longer range and can be fueled faster, but hydrogen is in short supply in many parts of the country and is currently a lot more expensive than electricity. Significant investments are being made by the federal government and private industry to increase future hydrogen supply, but most of this new capacity will not be available until 2030 or later.

The reality is that zero emission technology is not a “one-sized fits all” decision. The best choice for one agency may not be right for others. Ultimately, the decision requires a detailed evaluation of the full ecosystem encompassing energy production and supply, vehicle procurement, infrastructure development and workforce training.

Here are twelve considerations to help evaluate which technology is the right fit for your agency.