Climate Tech

The lightest, most abundant element could also be key to a net-zero future

Hydrogen can be a sustainable alternative to fossil fuels—but only if it’s made with renewable energy.
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The lightest and most abundant element in the universe could become an important energy source in a decarbonized future.

Hydrogen is already used today to refine fuels and create ammonia, but “virtually all of it is made from fossil fuel,” Janice Lin, founder and president of the Green Hydrogen Coalition, told Emerging Tech Brew. Now, companies and researchers are working on how to produce cleaner hydrogen and use it to power difficult-to-electrify sectors and store energy from intermittent renewable sources.

Although it’s not expected to be a dominant energy source, the International Energy Agency (IEA) estimates that hydrogen could account for about 10% of global energy consumption by 2050 in a net-zero future.

Like fossil fuels, hydrogen is energy-dense and can produce very high temperatures when combusted. This makes it a potential substitute in industrial processes that require extreme heat, such as steel-making, or for long-haul transportation needs that can’t be met with today’s battery technology, like aviation, heavy trucking, and shipping. Hydrogen could also provide a way to store energy from renewables for months, compared to the hours of capacity batteries can handle.

“It can be stored similar to how we store natural gas,” Anne Robba, manager of future energy signposts at S&P Global, told us. “When you have this excess of renewable capacity, you can run your electrolyzers to make the hydrogen and then store it.”

While it is actually more energy-dense than natural gas, hydrogen doesn’t exist naturally on its own. It’s commonly found coupled with oxygen in water (H2O) and with carbon in methane (CH4).

“It’s not a fuel on its own, and it takes energy to make energy,” Robba said. “To get a lower carbon-intensity hydrogen, you need renewables, and you lose about 30% of your energy with that.”

This energy loss makes hydrogen a weaker candidate for power-generation applications, like providing electricity to a house.

The H2 rainbow

Hydrogen comes in several colors—green, blue, gray, brown, or black—all of which indicate a difference in how it was produced.

  • Brown or black hydrogen is made from coal through a process of gasification that releases CO2.
  • Gray hydrogen is produced through a process called steam reforming, which separates hydrogen from natural gas, typically methane. This method also produces CO2.
  • Blue hydrogen refers to hydrogen separated from natural gas using steam, and uses carbon capture and storage tech to trap and sequester emissions from the process.
  • Green hydrogen, broadly, refers to hydrogen that is separated without emitting greenhouse gasses. Often, that means it comes from electrolysis, where hydrogen is split apart from water using electricity.
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Most hydrogen used today is gray, Robba said. But since 2021, S&P Global has tracked a 350% increase in announcements for low-carbon projects—meaning both green and blue hydrogen.

“The lower-carbon hydrogen is really in the beginning stage of its development. I would say 5%–10% is made from green hydrogen,” she said.

One of the main challenges for clean-hydrogen adoption is its price. It can cost between $3-$7 per kilogram today, while hydrogen made from natural gas costs a maximum of $1.50 per kg. The DOE’s goal is to get the price down to $2 per kg by 2025. Separately, the cost of green hydrogen is dropping faster than previously expected due to plummeting costs of renewable energy and electrolyzers.

The bipartisan infrastructure law provides $9.5 billion in funding for hydrogen projects in the US, including $8 billion for at least four clean-hydrogen hubs.

In April, the DOE’s Loan Programs Office issued a conditional commitment for a $504 million loan to finance a clean-hydrogen project in Utah. The facility will convert energy from renewables into hydrogen using electrolysers and then store up to 300 GWh in two massive salt caverns. The project’s planned completion date is 2025.

Early days

At this point, even the definition of green hydrogen remains a debate within the US hydrogen industry.

“When we say ‘green hydrogen,’ we’re talking about hydrogen that’s produced not from fossil fuels. So it’s coming from a renewable resource—can be made from water, from organic waste, [or] biogas,” Lin said.

The infrastructure law defines clean hydrogen as a maximum of 2 kg of CO2 emissions per 1 kg of H2 produced, but Lin said the DOE will have to clarify how to measure that CO2 output.

Then there’s the question of infrastructure. Natural-gas pipelines might be able to carry hydrogen, but it’s much lighter than natural gas, creating concerns about leaks. Transporting hydrogen in liquid form would require much colder temperatures than liquid natural gas, meaning greater energy usage.

And—as with most other climate tech—truly green hydrogen depends on a cleaner energy grid.

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