ALTERNATIVE ENERGY: What’s the big deal about hydrogen?

CHENNAI: Hydrogen is the most abundant element in the universe, which is probably why it deserves pole position on the periodic table. It’s a colourless, odourless and non-toxic gas that consists of a single proton and a single electron. It’s also highly combustible. Each kilogram of hydrogen or H2 contains about 2.4 times as much energy as natural gas. Impressive, right? It is. Industry has long been in on the benefits and has been using hydrogen for decades in the petrochemicals sector — mainly for oil refining, producing ammonia for fertilizers, and in the production of methanol and steel. But it has also been touted as a means of speeding up our transition to clean energy. Even the European Commission has described hydrogen as “the missing part of the puzzle to a fully decarbonised economy”. German Chancellor Olaf Scholz also sees it as key to reducing reliance on Russian gas and reaching climate targets: the country has signed a deal with Canada to begin importing hydrogen on a large scale from 2025.

It’s a clean, versatile fuel that doesn’t produce any direct greenhouse gas emissions — all it takes to release the energy is oxygen, and the only byproduct is water. It could potentially help some polluting sectors slash their CO2 emissions. Think heavy-duty transport or buildings, where hydrogen could be blended into existing natural gas networks for heating. But it could also be used to store renewable energy in the power sector and replace fossil fuels in chemicals and fuel production.

Let’s not get carried away. Thing is, hydrogen doesn’t exist on this planet in its pure form. It’s great stuff once you can get your hands on it, but unlike fossil fuels, it’s not just lying around waiting to be dragged from some ancient slumber. In fact, separating it from other substances so we can store and use it requires time and energy. Which also equates to money. The hydrogen catch is how it’s made. From an environmental perspective, the energy-intensive ways of extracting it become secondary if it’s produced without CO2 emissions. But that is by no means always the case. Ranging from clean to dirty, the myriad H2 production methods are complicated. And what do we do when things get too complex? Not advisable. No, we introduce a snazzy color scheme. So for the next couple of paragraphs, maybe try to forget that hydrogen is in fact a colourless gas.

The most common form of H2 used today (ca. 95%) has been labelled gray hydrogen. If that calls to mind emissions, that’s about right. Every ton of the gray variety comes with a footprint of about 10 tons of CO2 emissions because the production process — also known as steam methane reforming or SMR — relies on gas or fossil fuels. Blue hydrogen sounds a lot cleaner. But that’s just color trickery because it is, in fact, also produced with methane. The only seemingly redeeming feature is that the CO2 emissions from the production process are captured and stored underground. Pink hydrogen, which has a 1980s ring to it, relies on nuclear power. So while it might work in some countries where nuclear is big, it’s not a global solution. It’s also not pink.

Other versions include brown, black, yellow, turquoise and green hydrogen. To cut to the chase, the only one that makes any real sense in terms of reducing our carbon footprint, is green. That’s because green hydrogen is made via electrolysis (splitting water into oxygen and hydrogen) with the help of renewable energy. This means zero CO2 emissions and no mess to clear up. And it wouldn’t harm global water supplies either. That said, it currently makes up less than 1% of global hydrogen production.

This article was provided by Deutsche Welle