Shifting to hydrogen is a major part of the energy transition and is essential to achieve the UK’s Net Zero emissions target, experts from the University of Edinburgh-supported £1.4m HyStorPor project report.
The multi-institution HyStorPor project (partners include Scottish Carbon Capture and Storage, The University of Edinburgh, Heriot-Watt University, Imperial College London and SAMS) has been investigating hydrogen storage in the subsurface as part of the UK's future low-carbon energy mix, culminating in a final conference at ECCI in July.
The project also includes a multidisciplinary information hub on hydrogen usage and storage, based at the University of Edinburgh.
Scottish Carbon Capture and Storage (SCCS) Director and Professor of Carbon Capture and Storage Stuart Haszeldine said: “When we started three and a half years ago people questioned why we were looking at hydrogen storage in porous media,”
“Sentiment changed pretty rapidly. The project has benefited from leadership by Dr Katriona Edlmann and Dr Mark Wilkinson; and has been spectacularly successful in publishing journal papers – 34 in total covering a huge range of output with a strong international reach.”
Being able to store large amounts of hydrogen is key to the energy transition and to the move to renewable sources. When electricity demand is low, wind and solar power can be converted into hydrogen and stored, before being drawn down and turned back into energy when demand is high.
"At present, we are storing very little power – just 3GW worth, a number which will need to rise to 20GW by 2030 and 30GW by 2040" said Prof Haszeldine "but we also need to plan for multi-week periods when wind energy output is small. That means storing 60-120 TWhr of energy for the UK. That’s a huge amount and way beyond the present 0.03-0.3 TWhr so that batteries or pumped storage have tiny reserves. That’s why we calculate that hydrogen storage will be essential."
"As a result of the HyStorPor project, geological aspects of site selection are much more clearly understood" Professor Stuart Haszeldine said. "The project’s research suggests that storage reservoirs hotter than 122 C or with salinities above 5.1 M NaCl equivalent will be less favourable to microbial growth – and so will be favoured for hydrogen storage. No significant geochemical reactions of porous reservoir rocks or overlying seal rocks have been observed in our reactive experiments. Calculations indicate that the caprock will retain a thicker column height of hydrogen than methane and that this increases with increasing depth, so will securely hold the hydrogen in place. We have identified huge significant storage capacity in depleted gas fields, minimising subsurface competition with other low carbon geoenergy applications such as Carbon Capture and Storage, heat mining or Compressed Air Energy Storage. Salt caverns in domes and bedded salt also show good promise, and are abundant beneath NW and east England, offshore of Scotland, and in Europe."
Associate Professor Grant Wilson of the University of Birmingham re-enforced the need for immense energy storage with hydrogen in that mix. He noted that in future the UK energy system will need to cope with back-to-back low-wind events, potentially at times of year during the heating season.
“This strongly suggests the need for low-carbon sources of stored energy at a minimum range of 10s of TWhs of electrical energy equivalent to be drawn upon over days to weeks,” he told the conference. “These could be nuclear, interconnections of low-carbon electricity or gas, hydrogen storage within national boundaries, or low-carbon energy imports of some sort via shipping. It’s likely that all of the options will be used to some degree in Great Britain, as a portfolio approach to energy system balancing over days-to-weeks and seasonal timeframes has benefits.”
Hydrogen essential for Net Zero
Stuart McKay, Head of Hydrogen Policy in the Scottish Government also spoke at the event, reinforcing that Hydrogen is essential to achieve the UK’s Net Zero emissions target because we cannot electrify everything. Key sectors such as heavy transport, industrial heat and some parts of the domestic heat networks will require hydrogen gas for power.
“I would like hydrogen to play a role in balancing the energy system and providing storage in the short and medium term for the electricity grid as more renewables come online. I would also like to see it playing a role in decarbonising industrial heat and particularly the distillery sector – that’s the lowest hanging fruit.” - Stuart McKay, Head of Hydrogen Policy in the Scottish Government
Being able to store large amounts of hydrogen is key to the energy transition and to the move to renewable sources. When demand is low, wind and solar power can be converted into hydrogen and stored, before being drawn down and turned back into energy when demand is high. He said the Scottish Government, which published a hydrogen action plan in December, supports blue and green hydrogen but that it doesn’t support any new grey hydrogen coming online. Green hydrogen is hydrogen produced with renewable energy; blue hydrogen is hydrogen produced with natural gas with carbon capture and storage; while grey hydrogen is hydrogen produced with natural gas without capturing the greenhouse gas emissions made in the process.
Mr McKay predicted that the pattern of Scotland’s hydrogen production map would remain diverse with both small and large producers.
“There will be small regional hydrogen projects which are green and which are coming forward and multiplying. There are also a handful of very large projects being proposed linked to the installation of offshore wind that are due to come online in the late 2020s,” he said, giving the example of the Repsol Sinopec 2GW Orkney Flotta project, the largest planned to date.
The Scottish Government is supporting the sector with two hydrogen innovation funds. The first, a £10m fund, is backing 32 projects, with a further £90m fund due later this year.
In terms of the hurdles currently faced by developers, these include securing firm offtakers for the hydrogen and also uncertainty over some aspects of the regulatory framework.
“We’re also aware of the pressure these projects will put on local planning authorities to process planning applications,” he said.
University research has a key role
As for how university research could support hydrogen deployment, Mr McKay said the efficiency of hydrogen production could be improved “immensely”.
“A better understanding of how that could progress would be extremely useful for Scotland’s prospects in hydrogen production,” said Mr McKay. “The design of electrolysers to be able to use salt water to produce hydrogen would be a potential gamechanger.”
Two key potential developments for hydrogen in Scotland depend on action from the UK government, he noted.
“A positive decision from the UK government on the blending of hydrogen into the gas grid would be a step change intervention in the hydrogen market in the UK and Scotland,” he said. “And a positive decision on the Scottish CCUS cluster from the UK government would be the catalyst for significant supply chain deployment and for blue hydrogen production in Scotland. That would make such a difference.”
Scottish Carbon Capture Storage
With a secritariat based at ECCI, SCCS is the largest carbon capture and storage (CCS) research group in the UK, providing a single point of coordination for CCS research, from capture engineering and geoscience to social perceptions and environmental impact through to regulation and economics.