What is Hydrogen?

A 2016 Toyota Mirai fuel cell vehicle at a Southern California hydrogen fuel station. Toyota Motor Sales

This article was updated by Larry E. Hall, Hybrid & Electric Car Expert

Hydrogen is a basic element — remember the periodic table? The most abundant element on earth, it’s an elemental gas that is extracted from other compounds, not manufactured in the traditional sense like other fuels.

Most commercial hydrogen is reformulated from petroleum (natural gas), but can also be made by passing electricity through water (electrolysis). Although it is possible to burn it in an engine, sophisticated fuel management systems and expensive special fuel tanks are required.

Fuel cells that chemically alter hydrogen — not burn it — still tend to be the most efficient devices to create electric power from hydrogen.

While a few automakers have tested hydrogen powered internal combustion engine vehicles, the technology has largely been dismissed. Today, research and development efforts are focused on hydrogen fuel cells that provide electrical power for electric motor vehicles.

Currently there are three hydrogen fuel cell electric vehicles available for lease in limited areas of California only: Honda Clarity (arrives summer 2016), Hyundai Tucson Fuel Cell and Toyota Mirai.

As promising as this technology is, there are only 21 public hydrogen refueling stations in the United States, three on the east coast, the balance in California.

Pros: A Yes Vote

  • Very clean: The only by-product from spent hydrogen is water vapor.
  • Safe and reliable: Has an excellent automotive and industrial safety record.
  • Plentiful resource: When extracted from water, not reformed from natural gas.

Cons: What to be aware of

  • Hydrogen is expensive to generate, handle and store.
  • It has a fairly low energy content in gaseous state used in automotive fuel cells.
  • Costly infrastructure: The cost to build a hydrogen refueling station is roughly $1.5 million.

Safety & Handling

  • Hydrogen requires careful handling and special storage tanks.
  • There are a variety of ways to store hydrogen: liquefying it, compressing it or micro pore storage (impregnated into carbon or graphite medium). How safe is hydrogen?


Good future potential. One of the biggest hurdles is building the refueling infrastructure.

Learn More: Hydrogen 101
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