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Hydrogen: The dream in the pipes ‘


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Hydrogen gas has received a lot of attention recently as the “green” alternative to fossil fuel gas. The Government sees hydrogen as a low carbon solution which can help the UK to achieve Net Zero by 2050, and its Sixth Carbon Budget target by 2035. A new Net Zero Hydrogen Fund has already been set up and is in the consultation stage to help support the transition to a low­ carbon economy. Russell Dean, head of residential heating, Mitsubishi Electric elaborates


omestic heating in the UK accounts for around 13% of greenhouse gases, according to the Climate Change Committee. In order to reduce our fossil fuel usage and reach Net Zero, domestic heating is going to have to change. There are a number of alternatives out there already with the first scaled tests of hydrogen being conducted in home heating. The Government’s own strategy expects around 10% of total UK domestic heat demand to come from hydrogen, and blue hydrogen at that, by 2030 (more on that further down).


Kicking the can


In this crucial climate decade that we find ourselves in, and in light of the stark realities painted in the recent IPCC report, as well as the devastating effects of climate change we are already seeing, is 10% by 2030 enough? If not hydrogen, then what are the alternative solutions that we can use to heat our homes at scale? Firstly, the investment in hydrogen is significantly more than alternative heating methods like heat pumps whose proven renewable technology is available today and can decarbonise our housing stock more effectively today, than hydrogen can start doing by 2030. Seeing climate returns by the end of 2030 with a fuel that is not only very energy intensive to create, but also not necessarily as emissions free as people are led to believe, leaves the question of what is being done between now and then to reduce the current and short-term future emissions. The Government also plans to leave open the question as to what colour hydrogen will we be relying on. But why is this important?


Green, blue or grey?


Green, blue, brown, even yellow, and pink. There are several colour categorisations for hydrogen, each offering varying degrees of fossil fuel use. The most common are grey hydrogen – created using natural gas without capturing the greenhouse gases made in the process. Blue hydrogen is also produced using natural gas, but the carbon dioxide produced as a by-product means carbon capture and storage is essential to consider this a “green” form of energy production. Green hydrogen is the cleanest iteration, where hydrogen is produced without any greenhouse gases, typically using clean electricity from renewable energy sources like solar and wind.


18 BUILDING SERVICES & ENVIRONMENTAL ENGINEER FEBRUARY 2022


Production of green hydrogen is expensive and requires battery storage technology to ensure a constant supply of hydrogen can be created, using an inconsistent form of energy. The Government’s plan for hydrogen across UK domestic heating is likely to be driven by blue hydrogen so still using fossil fuels in the creation process, limiting the clean results that will come from its use. Unless there is 100% carbon capture at the source of production for the hydrogen then the drive for Net Zero only gets further away. It’s clear that hydrogen does have a place in the low-carbon/net-zero future, but where?


Better uses for H


The opportunities for hydrogen lie in the heavier industries that are so far reliant on dirty fossil fuels. Industries like steel making, almost solely reliant on coal, are prime targets for hydrogen, as well as shipping, heavy vehicles like construction machinery and trains.


In Michael Liebreich’s Clean Hydrogen Ladder, hydrogen has been given a lot of important uses amongst industrials. It falls short however in domestic heating with Liebreich talking about how “using wind power to generate [green] hydrogen, and then using that for heat, would have a system efficiency of around 50%”.


Viable, existing alternatives


There is no argument that the UK’s housing stock needs to decarbonise rapidly to help support the country’s Net Zero goals. The Government has already pledged that no new homes will be connected to the gas grid as of 2025, with air source heat pumps (ASHP) being positioned as one the favoured technologies. The Committee on Climate Change is encouraging the installation of one million heat pumps a year by 2030 – significantly more than the 10% of heat hydrogen is promised to bring – to help the UK meet its carbon reduction commitments, to combat the current low levels of update in the UK. However, in 2019, only 8.5% of heat came from low-carbon sources and despite their efficiency and environmental benefits, the number of heat pumps installed in 2019 fell below the number needed to meet the one million target by 2030. Concerted government effort, and financial support, is needed to ensure the million target is hit. The rapid training of installers and financial benefits like the Renewable Heat Incentive (RHI) and Green Homes Grant are essential to encourage the uptake. There is also the question of what happens to those homes that aren’t even


The potential for a low­carbon future


with hydrogen as a replacement fuel is great. With a transition to green hydrogen in heavier polluting industries, we can look to increase the difficult challenge of decarbonising our economy.


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connected to the gas grid. Roughly 1.5 million homes in the UK do not have access to the mains gas grid and subsequently use older methods for home heating, like LPG oil. Ensuring these homes are retrofitted with renewable heating solutions that don’t require connection to the grid, like heat pumps, will deliver a significant carbon saving.


No silver bullet


The potential for a low-carbon future with hydrogen as a replacement fuel is great. With a transition to green hydrogen in many of the heavier polluting industries, we can look to increase the difficult challenge of decarbonising our economy. The possibilities of using hydrogen in home heating however have not yet proven themselves able enough to overcome the challenges and the looming questions that remain about the hidden carbon in the processes. By putting the question of decarbonising home heating off until 2030 flies in the face of logic. It’s time to invest in proven technologies, now, that can start to address the issues before it really is too late.


As with all things climate change related, it’s clear that there is no silver bullet that will decarbonise one specific industry. Multiple different solutions, working in tandem and parallel with one another is the best way to ensure not only energy diversification, but to deliver on the promises of Net Zero by 2050.


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