hydrogen on board

August 23, 2007

A tremendous amount of research and development supports the fuels used in cars and trucks today, and much of that R&D is helping reduce emissions. But what fuels will future generations use?

They might drive vehicles powered by hydrogen fuel cells.

Hydrogen molecules, or H₂, are highly-efficient energy carriers which, when used in a fuel cell, emit only water vapor from the tail pipe. Hydrogen-powered fuel cell vehicles could improve energy use and lower carbon emissions, bringing important benefits for consumers, the environment and energy security.

But there’s a catch. On Earth, hydrogen molecules rarely exist by themselves. They must be made from other compounds and then delivered efficiently to be used for vehicle fuel cells.

Most prototype fuel cell vehicles on the road today use hydrogen that has been manufactured in a process unit, then compressed or liquefied before being delivered to distribution points and stored in a tank at high pressure on board the vehicle. This process uses energy and produces greenhouse gas emissions. Also, widespread adoption of these vehicles would require a new and expensive infrastructure to produce and deliver hydrogen. There are safety concerns associated with transporting and storing hydrogen on board vehicles, too.

But together with partners in industry and the research community, ExxonMobil is developing a technology that we believe could help solve these problems: an innovative on-board hydrogen-powered fuel cell system.

How does it work? This system converts conventional hydrocarbon fuels such as gasoline or diesel into hydrogen for a fuel cell right under a vehicle’s hood. No new power plants or service stations required.

The benefits are clear. Measured on a “well-to-wheels” basis, this on-vehicle hydrogen fuel system could be up to 80 percent more fuel-efficient and emit 45 percent less carbon dioxide than today’s internal combustion engine.

This pioneering technology, which has been under development for the past five years, will first be targeted at warehouse vehicles such as forklifts. Some day, it could be applied to passenger vehicles.

There is still a long road ahead. It will require sustained effort and could be decades before this technology reaches consumers. But thanks to groundbreaking work by ExxonMobil and others, hydrogen on board is one of the many promising vehicle and fuel innovations on the horizon.