The truth is that hydrogen is only as good as the energy source that is used to make it. If the hydrogen is generated from renewable electricity breaking down water – known as electrolysis – then there are no carbon emissions and burning the fuel simply produces water vapour. This is called ‘Green Hydrogen’ and will make up at least half of the UK’s target.
The rest of the Hydrogen will primarily be ‘Blue Hydrogen’ which is created from reforming natural gas (a.k.a. Methane) and capturing and storing the produced Carbon Dioxide. This may sound good in theory, but the reality is far from it. Consistent leaks of environmentally harmful Methane undermine its effectiveness, and there is no evidence to suggest that carbon capture could work at the required efficiency of 95% and at the scale needed.
Yet, many policy makers and companies continue to claim it is an essential part for the transition to ‘Green Hydrogen’, despite the fact that new renewable energies in the UK have been cheaper than new gas facilities for the last several years.
Mark Jacobson, professor of civil and environmental engineering and director of the Atmosphere/Energy Program at Stanford University says: “Blue hydrogen is basically nothing but a smokescreen for more air pollution, mining, and fossil fuel use with hardly any CO2 benefit.”
However, the real question is, even if Hydrogen was produced completely carbon-free, would it be the holy grail fuel to solve the climate crisis?
While ‘Green Hydrogen’ has great potential in specific sectors, don’t expect every home to be filled to the brim with this colourless gas any time soon. The latest research shows that green hydrogen is unsuitable for home heating with alternatives such as electric heat pumps with good insulation being much more effective. This is because using renewable energy to convert electricity into hydrogen requires more steps (with each step losing energy) than simply using the renewable electricity directly.
The main issue is that gases are difficult to store. Hydrogen often needs to either be compressed to take up less space or stored as a liquid at extreme cold temperatures (–253 ˚C), both of which require a lot of energy.
Additionally, Hydrogen safety and transportation continue to be issues too. Hydrogen is a very flammable gas – as demonstrated by the Hindenburg Disaster of 1937 where a Hydrogen zeppelin caught fire and exploded – and it is a small enough molecule that leaks can penetrate through most non-metals, or cause ‘embrittlement’ and cracks in most metals.
Advances do continue to be made in terms of hydrogen storage (e.g., injecting the gas into salt caverns), transportation (e.g., advanced stainless steel alloy pipes) and safety (e.g., sophisticated leak detection systems). This is fortunate as some industries such as ammonia and steel production will very likely require ‘Green Hydrogen’ in order to decarbonise.
Although, the real gem in using this gas comes in the form of long-term energy storage. While electric batteries are more effective on the timescale of days, ‘Green Hydrogen’ is far more effective on the timescale of months. This means, for example, that when a solar farm produces excess amounts of energy in the summer this can be stored for the winter when solar power is less abundant.
Despite how ambitious a government target may be, it is clear that there is no silver bullet solution to the climate crisis. However, using ‘Green Hydrogen’ for the decarbonisation of difficult industries and for long-term renewable energy storage is likely to be a positive step forward. And we will need all the positive steps we can take if we are to confront the biggest challenge that we, as a planet, must face.