Hydrogen fuel cell block diagram

Hydrogen has great promise in producing electricity because it has no byproduct but water. Potentially, it also has advantages over batteries as a storage medium.

That doesn’t mean we’ll be driving hydrogen fuel cell vehicles (FCVs) or storing renewable energy in fuel cells any time soon.

Pure hydrogen doesn’t exist in nature. Manufacture of hydrogen requires natural gas, biomass, alcohol, or water. The technology won’t be ready for prime time until some problems are worked out.

Current hydrogen technology

Using natural gas to produce hydrogen, fuel cells offer much higher efficiency than internal combustion engines and higher storage capacity than batteries. It takes no more time to refuel an FCV than to fill a conventional car with gas.

Producing hydrogen from fossil fuels produces carbon dioxide (CO₂) as a major exhaust. Technology exists to capture it, but long-term storage hasn’t yet proven feasible.

Critics complain that hydrogen made from natural gas is not a green fuel. They claim that electric vehicles have made much more progress in using green fuels. Solar and wind power can charge the batteries.

Current battery technology has its own environmental issues. FCVs emit about the same amount of CO₂ as a gasoline hybrid car or an electric car charged from the grid.

These renewable fuels can’t yet produce, store, and deliver enough hydrogen for automotive hydrogen fuel cells. Researchers are exploring how to use renewable energy, but battery technology has advanced more quickly.

Making hydrogen from water would seem greener than making it from natural gas. It uses a process called electrolysis to separate the hydrogen from the oxygen. With current technology, electrolysis costs too much to be commercially viable. It costs about ten times as much as a diesel generator with the same output.

Fuel cells have a much higher storage capacity than batteries (for small-scale use) or pumped hydro or compressed air energy storage (for large-scale use).  But the round-trip efficiency of electricity in and out of the system is only about 30-40%.

Innovations in hydrogen fuel cell vehicles

Toyota hydrogen fuel cell at the 2014 New York International Auto Show

Right now, the public seems more receptive to electric vehicles (EVs) like the Tesla or the Nissan Leaf than FCVs.

It’s easy to forget that EVs have existed for more than a century. Internal combustion engines drove them out of the market only in the 1930s.

The Tesla exceeded expectations and got rave reviews in 2011. The public became interested in them again only then.

It’s too soon to declare final victory for EVs. Auto makers, including Toyota, Honda, General Motors, and Audi, continue to develop FCVs.

Two startups, Joi Scientific in Florida and HyperSolar in California, have devised technology to turn seawater into hydrogen and bypass standard electrolysis technology. Both companies claim their process mimics photosynthesis to turn water into hydrogen inexpensively.

Their technology also bypasses the need for storage and transportation. It produces hydrogen close to where it is needed. Fueling an FCV vehicle will supposedly become as easy and convenient as filling a gas tank.

Can either or both company scale up their processes so that hydrogen fueling stations become as common as gas stations?

Innovations in energy storage with hydrogen fuel cells

Electrolysis. Water to and from hydrogen and oxygen

A French energy company, Engie SA, is building a demonstration project on Semakau Island, Singapore’s landfill. It will construct a microgrid powered entirely by renewable energy. It aims to solve the problem of intermittency using hydrogen storage.

Didier Holleaux, Engie’s executive vice president, says that batteries work best for short-term needs. Hydrogen fuel cells discharge more slowly than batteries. They can therefore provide power for multiple cloudy days.

The process uses renewable energy for electrolysis, and stores the hydrogen. When it’s needed, the hydrogen is pumped to a fuel cell to generate electricity.

So far, electrolysis costs too much for this process to be commercially viable. It will probably take 10-15 years to design a less expensive and more efficient electrolysis system. (Unless the processes under development by Joi Scientific and HyperSolar can bypass it sooner.)

Meanwhile, isolated communities with no access to power plants can benefit from microgrids with hydrogen storage. Indonesia alone has almost a thousand islands where people have no access to electricity.

What would be prohibitively expensive in most of the world can enable such remote areas to obtain electricity without ever having suffered the environmental impact of conventional power plants.

Sources:
Don’t believe the hydrogen hype: Hydrogen energy is not green / Angelo Young, Salon. June 11, 2017
The fascinating evolution of the electric car / Cadie Thompson, Business Insider. February 15, 2017.
Green cars 2.0: how do hydrogen fuel cell cars work? / Alex Jefferson, Proctor Cars [2015?]
Hydrogen energy storage: executive summary / Energy Storage Association
Hydrogen production and storage: R&D priorities and gaps / International Energy Agency. 2006
Solar energy fuels HyperSolar’s hydrogen dream / Tina Casey, Clean Technica. January 29, 2016
This startup just launched with a new way to turn seawater into hydrogen [Joi Scientific] / Katie Fehrenbacher, Fortune. February 16, 2016
A tiny island off Singapore may hold keys to energy’s future / Dan Murtaugh, Renewable Energy World. May 26, 2017
What’s the “hydrogen economy”? / Nigel Brandon, The Guardian. October 11, 2012

Image credits:
Hydrogen fuel cell block diagram. Public domain from Wikimedia Commons
Toyota hydrogen fuel cell. Some rights reserved by Joseph Brent
Electrolysis collage. Some rights reserved by Karsten Theis