Clean or dirty: Is hydrogen the climate-friendly energy solution we need?

Hydrogen holds tremendous potential as a cleaner alternative to fossil fuels. Policymakers and industry are pouring hundreds of billions of dollars into hydrogen energy technologies.

But hydrogen takes lots of energy to produce. It’s also a leak-prone gas that can contribute to global warming when it escapes into the atmosphere.

Whether hydrogen helps the planet will depend on how it’s made, managed and used.

Hydrogen could play a key role in heavy industrial processes that are hard to electrify. But for needs like powering cars and heating homes, clean electricity from renewable sources will often be cheaper and better for the climate.

Hydrogen is the most abundant chemical element in the universe. Stars like our sun are mostly made of hydrogen.

On Earth, you can find hydrogen bound up in molecules of water, sugar and more — but it’s hard to find hydrogen on its own.

So when you hear about hydrogen in the context of energy, it’s usually referring to hydrogen that’s produced through energy-intensive processes like these:

• “Gray” hydrogen: Hydrogen is typically extracted from fossil fuels using processes that generate a lot of pollution — including emissions of carbon dioxide and methane, both of which are greenhouse gases that warm the planet.
• “Blue” hydrogen: This refers to hydrogen that’s extracted from natural gas under conditions in which carbon dioxide emissions are captured and stored, instead of being released into the atmosphere.
• “Green” hydrogen: This refers to hydrogen that’s created by using renewable energy to split water molecules into hydrogen and oxygen.

Green hydrogen is a promising climate solution — if it’s made using new sources of clean electricity, as opposed to drawing from existing resources.

When clean energy is available, using it to power cars and homes directly is more efficient than using it to produce hydrogen for those same purposes. What’s more, if we use existing renewable energy sources to make hydrogen, that could lead to more fossil fuel energy being pulled into the power grid to fill the gap.

Blue hydrogen has even bigger environmental challenges to overcome.

Many companies and governments are focusing on this type of hydrogen, but for blue hydrogen to be a viable climate solution, very strict standards for production must be upheld to prevent carbon dioxide and methane emissions from being released into the atmosphere.

Another problem: Using fossil fuels to make hydrogen could increase fossil fuel production and prolong the life of fossil fuel infrastructure, generating dangerous air pollution and greenhouse gas emissions.

Regardless of the way hydrogen is produced, the way it’s stored, transported and used also affects how clean it is overall.

Hydrogen is a leak-prone gas, and in addition, it’s sometimes released as part of normal operations at hydrogen facilities. But if lots of hydrogen enters the atmosphere, that would undercut the environmental benefits of switching to hydrogen.

Here’s what to know:

• Hydrogen can contribute to climate change. In the atmosphere, it triggers chemical reactions that increase the amounts of greenhouse gases including methane, ozone and water vapor. This leads to warming.
• Minimizing leaks and other emissions is crucial. A 2022 EDF study explained how unchecked hydrogen emissions can severely reduce the climate benefits of even the cleanest hydrogen systems.
• We have new tools to spot emissions. EDF scientists are part of a global research collaboration that’s using breakthrough technology to measure hydrogen emissions from real-world facilities. This will help us understand how much hydrogen is escaping, and from where.
• Pipelines must be designed for hydrogen. Hydrogen molecules are small, light, leak-prone, reactive and flammable. Their unique properties mean that putting hydrogen into existing natural gas infrastructure poses serious concerns for safety and the climate.
• Producing hydrogen close to where it’s used makes sense, as transporting hydrogen over long distances is likely to increase the risk of leaks.

And hydrogen emissions aren’t the only ones to worry about. The world must limit emissions of all greenhouse gases associated with making, moving and using hydrogen.

Hydrogen’s challenges mean we must think carefully about when and how to use it. Finding cleaner ways to power the world is vital. But switching to hydrogen isn’t always the best answer.

For heating homes and powering cars, electricity from renewable sources can usually do the job more efficiently and at a lower cost.

Hydrogen is best used in areas where clean alternatives are lacking — for example, in steel and cement production, or as a chemical for making fertilizer, jet fuel and ship fuel.

The bottom line: We shouldn’t divert clean electricity from the grid to make hydrogen for needs that electricity can serve directly.