Green hydrogen has its attractions and is being promoted around the world, although not all end uses are seen as good for it. The 100% Renewable UK lobby group has produced a draft position paper setting out the pros and cons of each hydrogen option. It says that ‘whilst we accept that achieving a unanimous agreement amongst a global community of energy experts informed by their own professional and academic backgrounds and their understanding of their own national and regional perspectives is unlikely, the consensus is such that it is possible to determine a broad hierarchy of uses for hydrogen commensurate with achieving the goal of a one hundred percent renewable energy future’.
In this context, it sees green hydrogen, made by electrolysis using renewable power, and used for decarbonising heavy industry, as being very attractive, as is using surplus renewable power to make hydrogen for bulk storage for power grid balancing. It sees its use for shipping too as a good idea. Its use for public transport and heavy freight are slightly less attractive, but still viable-e.g. for trains and buses and for long distance trucking. Possibly aircraft too. But its use for cars and home heating are frowned on as inefficient.
It says that electric cars and light commercial vehicles ‘offer clear advantages over hydrogen powered vehicles. With most journeys by private transport being short and charging times for small vehicles continuing to fall there is simply no benefit in investing in the extensive refuelling infrastructure (and accepting the energy efficiency losses) necessary for adopting hydrogen for these purposes’.
And it says ‘hydrogen is the lightest element, the smallest atomic size, and has a very low energy density, meaning it is highly inefficient as a source of heat’. It will take time, but instead of using green hydrogen for heating, it looks to ‘a combination of strategies including maximising energy efficiency and the installation of heat pumps, solar thermal and photovoltaic panels, and non-fossil-fuelled district heating systems’
By contrast, the 100% Renewable UK paper is strongly opposed to the use of fossil gas and Carbon Capture and Storage to make blue hydrogen. It says that ‘the deployment of CCS and the extraction of hydrogen from fossil fuels primarily serves to prolong the use of fossil fuels, and the profits the industry generates, long beyond the limited timeframe left to avert catastrophic climate change.’ Also understandable is its opposition to the use of nuclear power to make hydrogen, not least given its likely high cost. However, its position on green hydrogen for home heating is not shared fully by all. For example, although the recent Hydrogen Champion report noted that ‘domestically, heat pumps offer higher efficiency in terms of heat output per unit of energy input’ it added that ‘there is a need to take into account wider costs and barriers such as hard-to-insulate properties and electricity network constraints’. So it says there might still be a role for it, including for back-up heating.
That may be debatable, with heat pumps usually seen as best for heating, but it is clearly true that hydrogen has a role in some key non-heating applications, as the 100% Renewable UK position paper, and also others, accept. The UK is aiming for 10GW of green and blue hydrogen by 2030, with their being a debate over the relative proportions. For example, the Climate Change Committee thinks blue will lead and green hydrogen will have to wait a while - see my next post.
However, although its use in the various end-use sectors will vary, overall, with demand for clean gas rising, demand for green hydrogen does seem likely to expand around the world. For example, Africa has a vast renewable energy potential, for solar especially, mostly well suited to electrolytic hydrogen production (apart from where water is scarce), and, as fossil gas becomes scarce, markets for green hydrogen will grow. Indeed it is already happening. But there are issues - the market for green power elsewhere e.g in the EU, will no doubt also grow and be very lucrative and that it will detract from the use of green sources for Africa’s energy needs.
There are also other potential expansion zones and also potential issues elsewhere for green hydrogen. For example, it has been much talked of in the USA. However, there are problems. The new federal tax credit rulings may make it harder to get full funding for green hydrogen produced using solar PV, given the tight criteria that have been adopted for carbon emissions. Hydrogen Insight notes that ‘green hydrogen produced wholly from solar power would not be able to receive the top $3/kg rate of the US production tax credit (PTC) due to the upstream emissions from the manufacturing of solar panels, according to figures in a new report by the International Energy Agency.’ It adds that ‘only wind power made using the most eco-friendly turbines would qualify for the $3/kg PTC rate, due to the lifecycle greenhouse gas (GHG) emissions rules set out in last year’s Inflation Reduction Act (IRA)’.
We do want to minimize emissions and certainly few greens want us to use fossil gas derived blue hydrogen, given that emissions from that are much higher. So it's good that they may be blocked. However, the IRA ruling for green hydrogen may be too tight at least for the initial phase- until we have moved on to using lower carbon PV materials, and improved wind turbines. There are also proposals for very tight regulation about the use of local green sources - to avoid regional transmission blockage issues. And as Grist notes, IRAs proposals that ‘hydrogen producers must match their operations with these renewable energy resources on an hourly basis… means if they buy power from, say, a solar farm, they have to shut down when the sun goes down’. That really is a major constraint, likely to undermine electrolyser efficiency. How to kill off green hydrogen! Unless, maybe, it’s off grid and used/stored by niche prosumers.
While, as noted above, the 100% renewable UK position paper see some key sectors as being well suited to green hydrogen, but it suggests blocking some uses of it, and also of CCS. However it also says that ‘there may be a case for the development and deployment of biologically-enabled carbon capture and storage (BECCS) to mitigate the release of carbon dioxide from the production and use of biofuels’. Given the land-use and biodiversity issues, not everyone will agree with that, even if it could lead to net negative carbon emissions, although some global scenarios have included it. The new 100% renewable UK scenario produced by LUT does not seem to included it. Indeed, in it, although renewable e-fuel use expands rapidly, the biomass contribution progressively falls. See my earlier post, reporting on the London conference organised by 100% renewable UK, based on the LUT work. But LUT does see a role for Direct Air Capture, so as the allow for methane production from green hydrogen. Given that DAC needs quite a bit of energy to collect the small amount of CO2 in the atmosphere, that’s a bit debateable.
Clearly the use of hydrogen and its derivatives opens up a range of strategic issues and can lead to disagreements. I will be exploring some more in my next two post.
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