It’s a wonder that hydrogen fuel-cell vehicles aren’t more popular in cities around the world. Powered with the most abundant element in the universe and using technology that emits only water, hydrogen fuel-cell vehicles only number in the thousands. Electric cars, on the other hand, are expected to reach 4.5 million by 2020, according to McKinsey. Several car manufacturers, including Hyundai, Honda and Toyota, are aiming higher, though, and have set goals to sell hundreds of thousands of hydrogen-powered cars within the next few years, reports NPR.
But fuel cells are expensive, and methods used to split water molecules (H2O) into oxygen (O2) and hydrogen gas (H2), are energy-intensive. Currently, 95% of the hydrogen produced in the United States comes from natural gas, according to the Department of Energy. That makes environmentalists uneasy because an otherwise emission-free fuel is produced through fossil fuel extraction and development. But research teams are working on new ways to develop clean hydrogen using renewable electricity generated by the sun or wind. Here’s how.
Sun and Saltwater
From their vantage, about three miles from the Pacific coast, researchers at Stanford University in California see the ocean every day. Now they’ve found a way to use that abundant saltwater in a well-known process called electrolysis, a technique that uses electricity to split water into hydrogen and oxygen. The reaction typically occurs inside a unit called an electrolyzer, where a power source connects to an anode (positive end) and a cathode (negative end) submerged in water. When a certain voltage runs through the water, oxygen comes out of the anode and hydrogen gas bubbles out of the cathode. That gas can be captured and run through a fuel cell.
Researchers would like to produce hydrogen gas from ocean water, since it’s so plentiful. But negatively charged chloride particles in seawater salt can corrode the positive end of the electrolyzer, ruining the unit within hours of use. Relying on purified water is an option, but in a world where drought and pollution are increasing, fresh water is a diminishing resource.
Professor Hongjie Dai of Stanford and his colleagues think they have a solution. They discovered that if they coated the anode with a negatively charged material, it repelled the negatively charged chloride particles and reduced corrosion. The material they developed is layered, with a foam core made of nickel metal, surrounded by nickel sulfide, topped with nickel-iron hydroxide. In lab experiments, Dai and his colleagues were able to run up to 10 times more electricity through their multi-layer coating without the risk of corrosion. “I think we set a record on the current to split seawater,” Dai said in a press release.
They also made a solar-powered prototype machine that produced as much clean hydrogen as conventional technologies do that use purified water. If Dai and his team can scale up such a system, the hydrogen fuel they produce would be 100% emission-free.
Harnessing Wind for Hydrogen
About 10 miles north of the British mainland, a Scottish archipelago of islands, reefs and islets weather the battering winds of the Atlantic Ocean and the North Sea. Historically, the enclave, called Orkney, has relied on diesel fuel. Over the last decade, though, wind turbines have sprouted like weeds, and today the island community is home to the highest concentration of wind turbines in the United Kingdom, according to Orkney Renewable Energy Forum. Recently, efforts have been made to use the wind energy to generate clean hydrogen fuel. The idea is to use it to power ferries that regularly transport people and goods between the islands and the mainland.
Such a notion emerged on the small Orcadian island of Eday, which is home to about 150 people. In 2012, the community commissioned the installation of a 900-kilowatt wind turbine. The island is also home to a tidal energy site, which generates electricity from the motion of tides. Both renewable energy systems generate so much electricity that the residents had to figure out what to do with the excess. They decided to use it to produce clean hydrogen via electrolysis. By 2017, they had shipped the first delivery of hydrogen gas to the nearby island of Kirkwell, according to Community Energy Scotland.
That’s just the beginning, though. Representatives from the European Marine Energy Centre say they want to expand the production of clean hydrogen to power local vessels that rely on diesel.
Other Hydrogen Fuel-Cell Vehicles
Seafaring vessels powered by hydrogen fuel are just one of several new vehicles trading fossil fuels for emission-free fuel cells. For instance, hydrogen-powered trains and trams are rolling down the tracks in the United Kingdom, Germany and China. Hydrogen-powered aircraft are also coming online. The Skai eVTOL by Alakai Technologies, based in Fairfax, Virginia, the Element One by Singapore-based HES Energy Systems and the HY4 by HY4, based in Germany are just a handful of the newest examples.
The state of California is building out a network of hydrogen filling stations for cars between Los Angeles and San Diego. That kind of infrastructure on the ground could incentivize vehicle manufacturers to build hydrogen-fueled cars, and also encourage customers to buy them.
When it comes to the elements, hydrogen is literally number one. That’s its place on the periodic table, and hydrogen makes up more than 90% of all of the atoms in the universe, according to the Los Alamos National Laboratory. Expanding renewable energy resources such as solar and wind power could be humanity’s best chance at exploiting hydrogen’s full energy potential. If we can, we could power the world with zero emissions.