RailPAC: California needs to follow the rest of the world with overhead wire rail electrification

2 mins read

Brian Yanity, vice president-south of the Rail Passenger Association of California (RailPAC) explains why he believes electrification with overhead catenary wire is the most effective way to achieve the zero emissions operations of California’s mainline passenger and freight trains, as it has proven to be around the world.

It is unfortunate that unproven hydrogen technology seems to be the primary “zero emissions” rail technology option considered by the California Department of Transportation (Caltrans) and the California Air Resources Board (CARB) for the state’s intercity and regional trains.

The laws of physics mean that hydrogen-powered trains will always have inferior energy efficiency and be more complex compared to conventional catenary electric trains. Hydrogen is also inherently limited by its low energy density compared to other fuels. Hydrogen trainsets are several times more expensive than a standard electric (overhead catenary) train.

Other disadvantages stem from the inherent complexity of hydrogen supply chains, on-board storage systems, and drivetrains. More complex systems onboard mean more potential points of failure and higher costs. Future technological developments will not change these realities.  

Evidence does not support the view that more conventional overhead wire electrification is unnecessary, due to hydrogen and battery technology improving. Hydrogen trains are inherently less efficient than all-electric trains powered by overhead wire, due to the fundamental physical properties of the gas.

Conventional rail electrification, using an overhead wire, is more environmentally friendly and reliable than hydrogen propulsion in almost every respect:

  • The energy required to produce and store hydrogen requires three times more electricity than that needed to power an equivalent train directly with overhead wire from the grid. That means that using all-electric locomotives with pantographs will always have at least three times less impact on the environment than those using hydrogen.
  • The hydrogen supply chain, on-board storage systems and drivetrains are highly complex. That means more points of potential failure, less reliability, higher maintenance, and operating costs. Moreover, hydrogen-powered locomotives are several times more expensive upfront than standard electric locomotives powered from overhead catenary. The significant upfront capital cost of rail electrification infrastructure is often given as reason to use hydrogen power instead. However, rolling stock is also a significant upfront capital cost. Hydrogen propulsion will greatly increase the capital cost of new rail fleets.
  • Hydrogen-powered propulsion requires both batteries and fuel cells made from materials (e.g. lithium, platinum, rare earth elements) that inflict the significant embodied carbon and local environmental impacts of mining, processing and shipment. Directly powering a train with electricity, using an external source (overhead wire), avoids these ‘embodied’ environmental impacts.
  • Leakage of hydrogen from pipelines and storage tanks is a serious problem, not least because hydrogen itself is an indirect greenhouse gas. Also, hydrogen storage and fueling stations pose dangers to residents living near them. For example, the San Bernardino Country Transportation Authority hydrogen train fueling station in San Bernardino is less than 400ft from homes. Delivering hydrogen to rail fueling stations with trucks also poses dangers to the wider public. 
  • Most of the handful of hydrogen trains in use today get their hydrogen from fossil fuel sources, with overall carbon intensity per passenger-mile no better than normal diesel-powered trains. Until someday in the future, when hydrogen will primarily be from renewables via electrolysis, fossil fuels will continue as the energy source for hydrogen powered trains. At present, renewably produced green hydrogen is far more expensive compared to hydrogen sourced directly from fossil fuels.
  • Producing hydrogen from electrolysis requires fresh, distilled water. In dry regions like California where water is scarce, the available water supply is a serious issue. Making hydrogen from salt or brackish water requires desalination, with all the energy consumption and any local environmental impacts that entails. 

With regard to passenger trains, it is uncertain if hydrogen propulsion will have the “sparks effect” phenomenon documented around the world, where electrification caused significant increases in ridership because of reduced trip times, increased frequency (in part due to lower operating cost), fewer train breakdowns, and the enhanced comfort of a quieter, smoother, smokeless ride.

What California needs is a rail network with conventional overhead wire electrification as its backbone, with use of catenary-battery hybrids for relatively short unelectrified sections and on unelectrified branch lines.