Energy & Climate Change

Carbon hydrates, often known as “carbs”, are an essential part of life on earth. Photo by iStock

Clean hydrogen with nuclear

Hydrogen is not just our most common element, but a potential way to store clean energy.

Hydrogen (H) is everywhere, yet almost none of it roams free. It is very reactive, and therefore it’s usually stuck on other elements. Carbon hydrates, often known as “carbs”, are an essential part of life on earth. Water is also essential for all life, and it is a combination of hydrogen and oxygen, H2O. And then there are hydrocarbons such as fossil fuels, of which hydrogen is also an important part of.

We also use hydrogen for many things in various industries. The largest use cases are in making ammonia, from which we make nitrogen fertilizer, and in oil refining. Hydrogen can also be used to produce clean, emissions free energy. It has been touted as the clean energy source of the future for decades, if not a century.

But hydrogen is not really an energy source, because there is no source of free hydrogen on earth for us to tap into. It is often combined with oxygen or carbon, as we learned above. To get pure hydrogen, we must break the bond it has with other elements. And breaking this bond always uses energy. In the case of hydrocarbons, it also releases carbon emissions. Today over 90 per cent of the hydrogen we use is taken from fossil fuels such as natural gas, oil and coal.

Clean hydrogen

We can also produce hydrogen without direct emissions. When I was in 7th grade, our chemistry teacher had us try out electrolysis. It is done by putting an electrical current through water, and it breaks the bonds between oxygen and hydrogen, releasing the hydrogen gas. The presence of this hydrogen was proven in a rather spectacular manner by taking a lit match near the surface of the water. Free hydrogen tends to react rather violently to open flame as long as there is oxygen present as well. The main problem with clean hydrogen is that it takes more energy to produce it than we get back from it.

Now if we produce the electricity needed for the electrolysis cleanly with nuclear or renewable energy and produce hydrogen with that electricity, we get low-carbon hydrogen. We can then use that hydrogen to replace the fossil fuels based hydrogen in various uses. We can also expand our uses of hydrogen. One option is hydrogen-powered cars. We can even combine it with carbon dioxide (CO2) or carbon monoxide (CO) and make clean, synthetic hydrocarbons – the very same ones we use today to power our cars and aeroplanes.

It's possible to produce hydrogen without direct emissions.

If we capture the required CO2 from the atmosphere or from the oceans, or the “renewable” flow of CO2 coming from the smokestack of a pulp-mill, we are talking about carbon-neutral fuels. The carbon in this kind of fuel has been taken from the atmosphere, where it returns when the fuel is combusted.

In the case of fossil fuels, we are releasing carbon that has been safely stored away in the crust of the earth, which adds to the overall concentration of CO2 in the atmosphere and oceans, accelerating climate change.

Fossil hydrogen is getting more expensive

Historically it has been cheaper to take the hydrogen from fossil fuels and make our liquid fuels from crude oil in a refinery. But clean hydrogen has been receiving more and more attention and research funding in the last couple years, thanks to increasing worry over human-induced climate change.

One of the reasons that clean hydrogen has been too expensive has been the relatively high price of electrolysers. But as we start mass-manufacturing more and more of them, their prices will drop. If the cost of emitting CO2 increases as well, it will increase the cost of fossil-based hydrogen. At some point, these two will meet, and clean hydrogen will become cheaper than its fossil counterpart.

We are still somewhat far away from that. Especially if we produce our clean hydrogen with variable renewable energy such as wind and solar, the cost of clean hydrogen will remain uncomfortably high for the time being. This is due to the electrolysers only running part of the time, when it is sunny or windy, instead of running 24/7. Even if an electrolyser runs only 20 or 40 per cent of the time it still must cover its investment and fixed operating costs fully.

What about small nuclear reactors?

So far, clean hydrogen research has been focusing only on variable renewables such as wind and solar. One of the main motivations for this might have been the realisation that we need to do something with the eventual over-production that they will have in our electricity system if we keep adding variable production. There has been less discussion on the fact that we could also use nuclear reactors to make clean hydrogen. This would enable 24/7 production and potentially much lower costs.

Yet it is clear that the current new nuclear projects in the United States and Europe have been rather expensive to build and are much too big for dedicated hydrogen production. The EU has also chosen to only support “renewable hydrogen” production, mainly because many of those making the decisions don’t like nuclear that much. But there are multiple projects for example in the US for so called nuclear hydrogen.

One of the options is to lower nuclear investments costs in the same way that we plan to do with electrolysers: mass produce them, and design them to be as low-cost as possible. Small reactors (SMR’s), which have attracted a lot of public discussion in the last few years, are especially well-suited for this since they are designed to be mass produced in the first place.

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