Person:

Hua, Charles

The transportation sector is the second-largest source of CO2 emissions, after electricity and heat generation, accounting for about 25 percent of global emissions.1 However, it is also one of the most challenging to decarbonize due to its distributed nature and the advantages of fossil fuels in terms of high energy densities, ease of transportation, and storage. Moreover, the degree of difficulty in decarbonizing varies significantly across the sector, making the challenge even more daunting.

So far, emissions reduction strategies have focused on improving vehicle and system-wide efficiencies, mode switching, and electrification. The latter is proving relatively easy for smaller vehicles that travel shorter distances and carry lighter loads. However, sector-wide decarbonization pathways will require a transition to low-carbon fuels and the deployment of enabling infrastructure to support innovation at scale.

Renewable hydrogen holds promise in sustainable mobility applications, whether by powering fuel-cell electric vehicles (FCEVs) like cars, trucks, and trains or as a feedstock for synthetic fuels for ships and airplanes. Fuel cells convert hydrogen-rich fuels into electricity through a chemical reaction. FCEVs use a fuel cell, rather than a battery, to power electric motors, and operate near-silently and produce no tailpipe emissions.

Hydrogen-powered vehicles offer key advantages, including shorter refueling times, longer ranges, and a lower material footprint compared to lithium battery-powered alternatives. However, high costs of ownership and a lack of enabling infrastructure are key challenges that must be addressed through policy support, technological innovation, and financial investment.

Hydrogen can complement existing efforts to electrify road and rail transportation and provide a scalable option for decarbonizing shipping and aviation. Figure 1 summarizes the mobility segments for which battery electric vehicles (BEVs), FCEVs, and vehicles running on bio- or hydrogen-based synthetic fuels are most applicable.

To accelerate the global transition to a low-carbon economy, all energy systems must be actively decarbonized. While hydrogen has been a staple in the energy and chemical industries for decades, clean hydrogen – defined as hydrogen produced from water electrolysis with zero-carbon electricity – has captured increasing political and business momentum as a versatile and sustainable energy carrier in the future carbon-free energy puzzle. But taking full advantage of this potential will require a coordinated effort between the public and private sectors focused on scaling technologies, reducing costs, deploying enabling infrastructure, and defining appropriate policies and market structures. Only in this way can we avoid replicating the system-wide inefficiencies of the past that have characterized regional approaches to deploying new energy infrastructure.