What Color Is Your Hydrogen? Not All Hydrogen Is Clean.

The Russian invasion of Ukraine and subsequent spike in fuel prices and inflation somberly reminds us of the destructive economic impact of our fossil fuel dependence. Meanwhile temperatures are rising as high as energy prices, and this summer’s deadly heat waves reinforce the human cost of climate change inaction. These dual threats raise the imperative for countries to get off fossil fuels, in particular natural gas, and make hydrogen a compelling clean energy alternative.

But, to help mitigate climate change impacts and decarbonize, that hydrogen must be truly carbon free. We can’t afford to invest in reputedly clean fuels that are more hype than substance. This is exactly the risk posed by certain types of hydrogen energy which are not carbon free.

While hydrogen’s profile has risen and fallen repeatedly over the past few decades, governments and industry are heavily investing in hydrogen energy with renewed vigor. The European Union recently announced €5.4 billion ($5.48 billion) in hydrogen subsidies, and the 2021 United States infrastructure bill included $8 billion in hydrogen investments. According to the U.S. Energy Information Administration, governments have committed about $37 billion and the private sector has announced another $300 billion for hydrogen production. EIA predicts a tenfold increase in hydrogen capacity by 2030.

But several red flags are hidden in these announcements. Unfortunately, many of these investments will produce hydrogen that will be worse from a climate perspective than fossil fuels. Most telling is that some of the fuel’s biggest boosters are fossil fuel companies. These groups seemingly support a fuel that promises rapid decarbonization but almost all hydrogen made today uses huge amounts of natural gas and other fossil fuels.

About 99% of hydrogen produced globally uses a steam-methane process, where methane comes from natural gas and the steam is produced by burning fossil fuels. The process separates out hydrogen by breaking down the methane into two components, hydrogen and carbon dioxide. This high carbon, energy-intensive process, produces what is known as “grey hydrogen.”

Its close cousin “blue hydrogen” is produced using the same process, but is touted as cleaner because its carbon is captured and stored. Neither “grey” or “blue” hydrogen produce carbon emissions when burned or converted into electricity, but methane leaks during production and transportation can make blue hydrogen worse than using natural gas.

Many other color variations exist along the hydrogen spectrum, but regardless of how many shades the hydrogen industry introduces, “green hydrogen” is the only color with a potential role in effectively decarbonizing the economy. Green hydrogen is produced by a fundamentally different process. Instead of steam-methane, it uses electrolysis—using renewable electricity to split water into hydrogen and oxygen.

So, from a decarbonization perspective, green hydrogen is the only hydrogen fuel that can help decarbonize the economy. But from a PR perspective, the lobbying by the oil and gas industry is unfortunately having a lot of success promoting blue hydrogen. Much of today’s hydrogen investment, including in the U.S. infrastructure bill, subsidizes both blue and green hydrogen production. The danger is that the hype over blue hydrogen might delay the world’s transition to renewables.

While the bottom line on hydrogen production is relatively straightforward, exactly what role green hydrogen should play in a decarbonizing economy is more complicated. Consider personal transportation, where hydrogen fuel cells were early contenders. Honda introduced its fuel cell car in 2008, and Toyota did the same in 2012. Despite fuel cell cars being introduced commercialized earlier than electric vehicles(EVs), hydrogen fuel cells have done nothing but lose ground to EVs ever since.

Fuel cell vehicles were outcompeted because electric battery costs have fallen over 90% in the last dozen years while EV range has surged past 300 miles and battery charging infrastructure has rapidly grown. In comparison, building fuel cell vehicle charging infrastructure is very expensive. Partially as a result, there are only 46 hydrogen fueling stations in the U.S., 43 of which are in California.

Today, hydrogen has effectively lost the race in personal transportation. A mere 25,000 hydrogen fuel-cell cars are on the world’s roads today and only two fuel cell vehicle models are commercially available in the US. In comparison, 15 million battery electric and plug-in hybrid vehicles are on the world’s roads, across 300 different models.

Hydrogen vehicles also have very low energy performance—comparable to that of gasoline and diesel vehicles, which use just 30-35% of the available energy in the fuel reaches the drive wheels. In comparison, battery electric vehicles use 70-80% of the available energy. The more energy required for transport, the more renewable energy needs to be generated, raising costs. All of which make it more difficult to decarbonize the economy rapidly and at scale.

The same results will likely play out in the commercial trucking industry, which is the only automotive sector where manufacturers are still hedging their bets on both EV and fuel cell technologies. Traton, a Volkswagen subsidiary that produces the Scania, MAN, and Navistar brands, is betting on battery electrics while Daimler and Volvo believe in fuel cells, but are also investing in battery electric trucks. Given the higher efficiency and the continuous cost reduction of electric batteries and lower cost of electric trucks, the majority of long-haul trucks are likely to eventually be electric.

So, what about hydrogen’s other capacities, like power storage or fueling ocean-going vessels? These are certainly possibilities, but all will have to contend with a fundamental problem. Electrolysis is a relatively simple, but a very inefficient production technique. In fact, if hydrogen was produced via electrolysis powered by average grid electricity supplies, it would have a carbon footprint as much as three times worse for the climate than fossil alternatives. Of course, as long as the electricity used in electrolysis comes from renewables, it’s still clean, but it demands a great deal of renewable electricity to produce the fuel.

Significant potential hydrogen leakage during production, transport, and use poses another fundamental problem. Hydrogen is what’s known as an indirect greenhouse gas— it accelerates greenhouse heating by the way it interacts with other gases in the atmosphere. This can lead to higher concentrations of methane, ozone, and water vapor in the atmosphere as hydrogen acts as a more potent greenhouse gas than carbon dioxide. Additionally, while hydrogen is odorless, tasteless, non-toxic—and extremely flammable and explosive, making safe storage a challenge.

Because producing renewable green hydrogen is so energy-intensive, the fuel can be useful in otherwise hard-to-decarbonize parts of the economy. Green hydrogen for example could power energy-intensive industrial process that aren’t easily electrifiable. Volvo recently announced that it is collaborating with SSAB, a Swedish steel manufacturer, to make carbon-free steel from green hydrogen.

In other modes of transportation, green hydrogen may prove useful as a fuel for ocean-going vessels and aircraft, both of which currently use petroleum fuels. Shipping company Maersk is investing in fuel cells or compressed hydrogen for its container ships, jet engine maker Rolls Royce is investing in hydrogen to fuel planes, and Jet Blue is investing in hydrogen fuel-based airplanes.

Hydrogen has a role in the decarbonized economy, but we must be wary of the fuel’s hype. Blue hydrogen is not a clean source of energy, but a marketing ploy by fossil fuel companies designed to expand the life of fossil fuels. Investing in blue hydrogen only delays renewables adoption. Green hydrogen investments need to be specifically targeted. This summer’s weather—deadly heat waves and catastrophic flooding around the world—has shown us how urgent it is to avoid any delays in decarbonization. We can’t be sidetracked by hydrogen hype.