Image: © Shawn Hempel/Stock.adobe.com
Dr Jason Power examines the feasibility of large-scale hydrogen production in Ireland in the context of the critical need to turn away from gas.
Energy costs and security have arguably never been more central in terms of public discourse. As the war in Ukraine rages, we are now acutely aware of just how fragile energy security is across Europe.
We will likely see gas supplies drawn into the economic conflict in the coming months as Russia attempts to prop up the ruble by forcing European nations to alter existing contract payment agreements.
While it is unlikely that Russia will cut supplies in the long-term, given that oil and gas exports make up approximately 40pc of the country’s GDP, it is likely that restricted supplies will be used to damage the European economy.
Race for renewables
Many have suggested that this further supports a rapid transition to renewables. However, Ireland’s main move towards renewables is based on wind power generation.
Wind power generation has typically been supported by gas power plants. These gas power plants can come online quickly when demand peaks or when calmer winds reduce production. They are also comparatively cleaner than coal power plants.
One alternative to burning natural gas would be to burn hydrogen. Existing gas plants could be refitted to run on hydrogen, but there are numerous challenges that must first be tackled if this is to be long-term solution for Irish energy security.
Not all hydrogen is created equal
There are two primary types of hydrogen that are commonly referenced when considering grid energy needs: blue and green hydrogen. The distinction is based on how they are produced and their environmental impacts.
Blue hydrogen is produced from natural gas and fossil fuel companies have lobbied extensively to have it included as a stepping stone away from fossil fuels and towards a net zero energy system. This type of hydrogen is created by reforming methane that is present in natural gas using a steam-based process.
However, a recent study suggests that blue hydrogen is even worse for the environment than simply using the natural gas from which it is made from to produce electricity. Critically, it also requires natural gas to be produced, and so offers little security or energy independence for Ireland.
Green hydrogen is produced by electrolysis. In this process, electricity is used to split water (H2O) into oxygen and hydrogen. This hydrogen is then pressurised in a tank and can later be burnt in existing gas power plants. In order for this gas to be considered green hydrogen it must be produced using renewable energy.
In many ways, this could potentially meet the greatest challenge of a primarily wind-based energy grid: energy storage.
When excess energy is being produced by wind farms, hydrogen production plants could begin to create and store hydrogen. When energy demand is at its highest, gas power plants running on green hydrogen could come online to help balance the grid.
With considerable investment in both hydrogen manufacture and storage these plants could also support the national grid for extended low-wind periods. Long-term, we could begin to export renewable energy to the UK through existing gas or grid connections.
Too good to be true?
If this system could solve our problems then why isn’t everyone doing it? There are a few reasons.
Firstly, there are not many countries that have the potential for wind energy production that Ireland has. Secondly, the technology required to produce hydrogen at this type of industrial scale is still in development. Finally, it comes down to cost.
We have had the luxury of relatively cheap natural gas energy for a long time. To build the infrastructure required to reach energy independence, we will have to dedicate a huge amount of our national resources towards these efforts in the coming decades.
In 2020, 57.1pc of our electricity was generated using gas while 22pc was generated using wind. When we create green hydrogen using electrolysis, approximately 20pc of the initial energy is lost due to efficiency. A further 50pc of the remaining energy would be lost when this hydrogen is burned in a gas power plant. Using this method, only 40pc of the initial electricity generated from wind ends up in our grid. In the simplest terms, if we wanted to completely replace natural gas for electricity generation with hydrogen that was manufactured using wind energy, we would need to increase wind energy production in Ireland by approximately 650pc.
This would not include other fossil fuels which contributed an additional 5pc in terms of electricity production in 2020. It also would not include the additional electricity required if we are to transition the national fleet towards electric propulsion or gas currently used for heating.
The manufacturing and storage infrastructure would also require considerable development. Hydrogen is less energy dense than natural gas so we would need much larger tanks. In order to create a secure grid we would need very large reserves, compared to current natural gas reserves, in order to meet demand in the event of low wind conditions.
Long-term vision
Green hydrogen will likely play a part in our national grid in the future. As a means of energy storage, it has considerable potential.
However, it is extremely unlikely that we will be capable eliminating our dependence on natural gas as a significant energy source within the next decade. Even our most ambitious wind energy targets fall well short of what would be required.
Despite these challenges, the urgent need to move to renewable energy sources remains. In the short-term we are beginning to understand the need for energy security and independence.
As we now recognise the danger of a weaponised energy supply, it is critical that we also recognise the longer-term threat of the climate crisis and the devastation that complacency will lead to.
There will be no easy answers to the challenges that we face, but long-term vision that goes beyond electoral cycles has the potential to benefit our society enormously in the coming decades.
Dr Jason Power is an engineering lecturer and course director at University of Limerick.
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