Using hydrogen for heat and power is not new, but its role in the energy transition is complex. We’ve distilled some of the key facts and reports on the role hydrogen can play in the energy transition to put things into perspective.
First thing’s first, what exactly is hydrogen?
Hydrogen is a chemical element which rarely exists on its own on earth. It is not a primary source of energy, and must be produced using existing energy.
In essence, hydrogen is best thought of as an energy carrier, not dissimilar to a battery.
But given the huge amount of energy needed to produce, transport and store hydrogen it is a very inefficient energy carrier. It’s likely it will not be available for use at a large scale.
Many governments and businesses are touting a clean hydrogen economy as the key to the energy transition.
The two forms of ‘clean’ or low-carbon hydrogen most commonly considered to decarbonise the energy system are green and blue hydrogen.
We know that to reduce the impact of climate change, we need to act today. This means using all solutions that we already have. Electrification is already cheaper and more widely available than green hydrogen solutions which are still in their infancy.
We should deploy zero emission green hydrogen for grey hydrogen first, followed only by niche sectors that don’t have existing electrification solutions.
Today the world produces 120 million tonnes of hydrogen annually. 98.7% of this is made from fossil fuels – natural gas, coal or oil – without CCS.
It is mainly used in making ammonia fertiliser for food production, for chemicals such as methanol and to remove impurities during oil refining.
This ‘grey’ hydrogen emits around the same emissions as the global aviation industry every year.
To decarbonise the grey hydrogen we’re already using today, we need almost three times the amount of wind and solar electricity that the world produced in 2019.
Given how much energy we will need to only decarbonise where fossil-based hydrogen is already polluting today, we need to take a prioritised approach to where hydrogen is used.
Facts on hydrogen and domestic heating
Both green and blue hydrogen are inefficient for heating
- Blue hydrogen made from natural gas and CCS uses at least 40% more gas than boilers using natural gas outright, and so would increase the gas imports of many countries, undermining energy security.
- Powering boilers with ‘green’ hydrogen uses x6 more renewable energy than the renewable energy used for heat pumps.
- Heating all the buildings in the UK with green hydrogen needs the UK’s existing offshore wind generating capacity to increase by a factor of 40. Using heat pumps would only require the existing offshore wind generating capacity to increase by a factor of around 6.5.
Facts on hydrogen and transport
Electric vehicle solutions are more efficient
What about blending hydrogen into the existing natural gas grid?
Some governments and businesses are considering blending up to 20% hydrogen directly into the natural gas grid to help cut emissions.
In most European countries, blending hydrogen into the existing natural gas pipelines won’t be possible beyond 20% hydrogen, before needing infrastructure retrofits.
A smooth transition between natural gas and hydrogen in our current natural gas pipeline infrastructure isn’t possible, as it requires a replacement of the existing natural gas infrastructure once blending limits are maximised.
Given how valuable (and inefficient) hydrogen is, blending it into the existing gas grid does not make sense due to its limited impact on emissions savings. Other sectors, like grey hydrogen, need to be decarbonised first.