Innovative Carbon Dioxide To Methane Technology Could Render Green Hydrogen Useless

Keep an eye on this space.

Photo by Avinash Shet on Unsplash

Renewable power is incredible. Not only does it have practically zero emissions, but, in particular, wind and solar are by far the cheapest form of energy ever! However, they produce power intermittently as the weather changes, meaning much of this incredible energy goes to waste. One prominent solution to this is green hydrogen, in which surplus renewable energy is used to split water into oxygen, which is released back into the atmosphere, and hydrogen, which we can harness as fuel, enabling us to use far more of the renewable energy we generate and fill in when the sun doesn’t shine, or the wind doesn’t blow. However, green hydrogen is inefficient, difficult to store, and expensive, and these disadvantages have massively limited the progress of this promising technology. Luckily, though, researchers recently found a brilliant solution that appears to have all the benefits of green hydrogen with none of the drawbacks.

So what is this technology? Well, a new catalyst in the form of nanoclusters of copper that, when given a zap of electricity, can turn atmospheric carbon dioxide into methane. This innovative technology was developed by researchers from McGill University, and initial results are damn promising.

We already use methane, also known as natural gas, for many applications, but it comes from geological deposits. This makes it a fossil fuel, meaning it contributes to climate change.

But, the methane produced by this catalyst doesn’t contribute to climate change as it has a close carbon loop. This means that the carbon emissions emitted when the methane is burned have been offset by the carbon emissions captured to produce the methane in the first place. As such, as long as the energy used to power the catalyst is renewable, this technology enables us to produce climate-friendly methane fuel.

As such, this new catalyst is being pitched as an alternative to green hydrogen. You see, hydrogen (green or otherwise) is incredibly challenging to store as it can leak from well-sealed containers and has an incredibly low density, both in terms of volumetric weight and volumetric energy density. It’s also very difficult to use as a fuel. You can burn it, but this is very inefficient, and hydrogen gives far lower power output than other combustion fuels. You can instead use a hydrogen fuel cell, but these are expensive, and practically no one has them to hand. Alternatively, methane is incredibly easy to store, has a high volumetric energy content but low volumetric weight, and the machines that utilise it as a fuel are plentiful. There are already a vast number of natural gas power plants worldwide and almost everyone has a boiler or hob that runs off methane, and combustion cars can easily be converted to run off it with no decrease in power.

As such, practically speaking, the “green methane” this catalyst can produce is superior to green hydrogen.

But it might also be more efficient.

You see, making hydrogen through electrolysis (as green hydrogen is) is, at most, 75% efficient. Hydrogen fuel cells, which are significantly more efficient than just burning hydrogen, are at most 40% efficient. As such, you can only get 0.45 kWh of useful energy back out for every kWh of renewable energy used to make green hydrogen. In other words, green hydrogen wastes 55% of the energy used to make it!

However, methane is one of the most efficient fuels in the world. It can reach a combustion efficiency of over 80%! This is why many LNG converted vehicles can travel far further using LNG than petrol. But, this also means that this innovative catalyst only needs to be 56.25% efficient at producing methane to have the same round trip efficiency as green hydrogen. Considering the researchers have stated that “Our top finding was that extremely small copper nanoclusters are very effective at producing methane,” I think we can safely assume this catalyst is more efficient than 56%.

So, this innovative catalyst potentially enables far more efficient carbon-neutral synthesis of fuels from renewable energy, but it also produces a fuel for which we already have the infrastructure and is far more useable than green hydrogen.

So, is this the end of green hydrogen? Will we all soon be driving around in green methane-powered cars? Will this enable our power grids to switch to 100% renewables, with the gaps in power generation being filled in by decades-old natural gas power plants running on green methane?

Possibly not. While this technology is utterly spectacular, it is in its infancy. We still don’t know how much it costs to construct such catalysts, let alone how efficient they actually are. What’s more, even once these questions have been answered, such technology would need years of testing before entire industries decide to switch to it. As such, this technology might not mature in time to displace green hydrogen. Nonetheless, having such technology at our fingertips is incredible, and it still could have a significant impact down the line.

---

Thanks for reading! Content like this doesn’t happen without your support. So, if you want to see more like this, don’t forget to Subscribe and help get the word out by hitting the share button below.

---

Sources: Phys.org, Science Direct, Plug Power, Canary Media, Nature.com, Research Gate