Is Green Hydrogen the key to decarbonisation and energy security?

The world is facing a seemingly impossible task in terms of energy security. To reduce carbon emissions there is pressure to transition away from fossil fuels and their derivatives. At the same time the demand for energy is increasing. While significant investment is being made into renewables such as wind and solar, challenges such as infrastructure and energy storage remain. Some are of the opinion that nuclear is the only “clean” way to bridge the gap, yet they conveniently forget the matter of nuclear waste disposal that is neither cheap nor easy, never mind the long term safety issues surrounding it. An alternative that is being put forward to reduce emissions and make more effective use of renewables, is green hydrogen.

How is Green Hydrogen different?

Hydrogen as an energy source remains somewhat controversial. Primarily because it isn’t a new technology and to date most hydrogen production is derived from fossil fuels – which does little to reduce carbon emissions. Green hydrogen, however, is produced from renewable sources such as wind and solar. But it gets more complex than that - there’s a rainbow of types of hydrogen which are named according to the materials and production methods used to generate it.

Black, grey, red or brown hydrogen are produced from fossil fuels either through methods of gasification or steam methane reforming (SMR). These methods do nothing to reduce carbon emissions and remain reliant on fossil fuels. As a result, while there is a sizeable portion of hydrogen produced in this way, it’s not at all sustainable or good for the planet.

Blue and turquoise hydrogen are seen as marginally better options to grey hydrogen. Blue hydrogen is derived from fossil fuels or methane, but the carbon is not released into the atmosphere, instead 85% to 95% of it is recaptured. Turquoise hydrogen is created through methane pyrolysis and the carbon is recaptured or used in industrial processes. This is being viewed as an alternate low carbon option, especially when looking to lower emissions in existing carbon intensive industries.

Purple hydrogen is created with nuclear energy as the source and still creates high levels of carbon emissions. Pink hydrogen is similar with the exception that the carbon is recaptured. As nuclear facilities generate high volumes of heat, this is viewed by some as a way to improve efficiency.

Green hydrogen is different from all of the above in that the energy is made by electrolysis and sourced from renewables such as wind or solar. It’s seen as a zero emission fuel, which when utilized in vehicles, for example, has a by-product of water vapour. This is one of the reasons there is an increasing amount of enthusiasm for green hydrogen as an alternative fuel.

What’s the catch with green hydrogen?

Given the potential benefits of green hydrogen, one might wonder why it’s only now being explored as an alternative fuel. One of the reason’s is that it requires large amounts of energy as an input, and to date there hasn’t been sufficient renewable energy generation to sustain green hydrogen production at scale. That is no longer a problem. If anything it’s a solution to the over generation of renewable electricity that sometimes can’t be utilized. If converted to green hydrogen, it could be stored for long periods of time, relatively cheaply underground, until it’s needed. This would go a long way to advancing energy security.   

A second reason green hydrogen production hasn’t caught on is the high production cost. However, as demand grows, technology and processes advance, and the economies of scale tip the balance, this becomes more affordable.

A third reason is hydrogen infrastructure. Hydrogen needs to be stored and transported under high pressure and currently very little infrastructure exists in the UK. One can’t just refuel anywhere which is a major reason that hydrogen passenger vehicles aren’t really taking off yet. By contrast, green hydrogen is seen as a viable alternative for heavy duty and long range vehicles. Hydrogen powered vehicles are more efficient, charge up in minutes as opposed to the hours  that EV’s take, and have a much longer range.  Plus they usually operate from depots which means that hydrogen infrastructure can be concentrated in major industrial hubs.

The UK government recently announced major investment in the development of green hydrogen and this has been met with a mixed reaction. Some believe it’s the ideal resource to bridge the gap to renewables and create more energy security. Others are voicing their concern that it will divert investment from renewables which should ultimately remain the end goal. There are valid points on both sides of the argument. However, keep in mind the need to rapidly accelerate decarbonisation and increase energy security and the part that green hydrogen could play in achieving this. There’s rarely a single best solution to a complex issue such as energy security, it’d be good to consider all available options. In doing so it may even create more opportunities and solutions that haven’t been considered before.