The promise of green hydrogen may not always be fulfilled

June 21. () –

Green hydrogen often, but not always, leads to increased CO2 emissions, according to new research published in NatureEnergy.

“If the full life cycle of green hydrogen production and transportation is calculated, rising CO2 emissions can be disappointing. However, if green hydrogen is produced from very clean electricity and locally, it can really help reduce emissions,” he explains. it’s a statement lead author Kiane de Kleijne of Radboud University and Eindhoven University of Technology.

It is believed that green hydrogen can make an important contribution to reducing greenhouse gas emissions. The EU also aims to produce 10 million tonnes of green hydrogen and import another 10 million tonnes by 2030. “Green hydrogen has great potential as a technology due to its versatility and many applications. ButUnfortunately, I still foresee some bumps in the road“says environmental scientist De Kleijne.

COMPLETE LIFE CYCLE

For more than a thousand planned green hydrogen projects, De Kleijne calculated the greenhouse gas emissions associated with the production of green hydrogen, including, for example, the production of solar panels, wind turbines and batteries to provide energy, and transportation by pipeline or ship.

“Green hydrogen is produced by breaking down water into oxygen and hydrogen in an electrolyzer using green electricity. That hydrogen can then be used as a feedstock or fuel. Hydrogen produced from natural gas is already widely used as a feedstock, for example example, in the chemical industry to produce methanol and ammonia for fertilizers.

The advantage of green hydrogen is that when water is decomposed, in addition to hydrogen, only oxygen and not CO2 is released. “However, that requires large amounts of green energy,” says the researcher. “Emissions can only be reduced by using green energy, such as wind or solar. But even then, the emissions from manufacturing wind turbines and solar panels alone add up considerably. If you look at the full life cycle in this way, green hydrogen often, but certainly not always, generates CO2 gains.. “CO2 gains are usually higher when using wind energy instead of solar energy. This will improve even more in the future, as more renewable energy will be used to make wind turbines, solar panels and steel for the electrolyser, for example” .

HYDROGEN TRANSPORTATION

Hydrogen production generates the lowest emissions in places where there is a lot of sun or wind, such as Brazil or Africa. The disadvantage is that this hydrogen must then be transported to Europe, which is technologically complicated and can generate many additional emissions. “Transporting green hydrogen over long distances contributes so much to total emissions that much of the CO2 gains from production in distant, favorable locations are negated,” says De Kleijne. For short distances, transportation emissions appear to be lower in pipelines, while shipping liquid hydrogen is better for long distances.

The key message, according to the scientist, is that we should not claim that technologies such as green hydrogen are completely emissions-free. The current calculation methods that form the basis of the regulations do not usually take into account the emissions of the elements necessary to produce hydrogen, such as solar panels and electrolyzers, nor hydrogen leaks during transport.

In those cases, it might seem like green hydrogen doesn’t produce many emissions, but that’s not the case. “If we look at emissions over the entire life cycle, we can make a better balance between technologies and identify where improvements can be made in the chain. Furthermore, we can ask ourselves: what is important to produce in the Netherlands and in Europe? And when would it be better to move an industry to another part of the world?” he concluded.