RESPONSIBLE TRANSPORTATION: WHY HYDROGEN POWERTRAINS NEED NET-ZERO GREEN HYDROGEN
A Rainbow Of Hydrogen Colours
Ironically for a substance that is transparent, almost every colour in the rainbow has been attributed to hydrogen, including green (from renewable energy), grey (from fossil fuel), blue (from fossil fuel with the CO2 being buried underground), pink from (from nuclear energy), and even gold (naturally occurring underground, and currently as rare as its namesake).
“What colour is the hydrogen in your vehicle powertrain?” may seem as random as asking “What colour is the battery in your EV?”, but it is actually a crucial question for the future of zero-carbon energy. Grey hydrogen is, in environmental terms, a complete waste of time. It takes a hydrocarbon (usually natural gas), applies energy in the form of steam to separate the hydrogen, and lets the unwanted CO2 escape to the atmosphere.
Blue hydrogen is the triumph of hope over experience: in theory, it takes the waste CO2 from grey hydrogen and stores it underground in disused caverns – forever. People have been talking about this since the 1990s, with experiments taking place since the early 2000s. In recent years, there has been an explosion of plans for blue hydrogen, but currently there are only two small-scale plants in the world, and according to a study by Cornell University, these offer no appreciable emission benefits - what they save in CO2 output is offset by additional methane emissions. It is as if a design for a new car started with “First, assume a perpetual motion machine.”
Green Hydrogen Is Becoming Cost Competitive
In contrast, green hydrogen is made from renewable energy used to electrolyse water to separate hydrogen and oxygen. Apart from the small amount of materials used in the electrolyser and wind turbines, or solar panels, it has no environmental impact.
Defenders of blue hydrogen say it is cheaper than green – or at least they used to say that. When gas cost 20 euros per megawatt hour (MWh), blue hydrogen cost around $2.50 per kilo, compared to around €4 for green hydrogen. But today, blue hydrogen would cost €10 per kilo – and each kilo of blue hydrogen results in 9 kilos of CO2 to dispose of.
No doubt, gas prices will fall from their current peak, but will they go back to their 2020 level? It seems unlikely that Europe will agree to open the Nord Stream 2 pipeline from Russia while Putin is in power, and the talk now is all about energy security. Importing more gas to turn into hydrogen might please the Kremlin, but who else would benefit?
In the meantime, prices of green hydrogen will fall steadily as production increases. While the cost of blue hydrogen might temporarily dip, green hydrogen will be cheaper from 2030 on any reasonable cost assumptions. If we are serious about developing sustainable cleantech solutions, we have to use materials which are genuinely zero-carbon. Taking the view that “Hydrocarbons plus magic equals net zero” is not the answer.
Green Hydrogen Offers Energy Security
In addition, recent geo-political events have firmly expanded the hydrogen debate from ecology to energy security, and with it, hydrogen has moved to centre stage as nations around the globe rush to free themselves from strategic reliance on oil and gas.
The hydrogen narrative has accelerated dramatically and as a result we can consign grey and blue hydrogen made from fossil fuels to history. Hydrogen’s future and our future will be green…
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