Hydrogen stored in salt caverns could be converted into flexible power source

Storing hydrogen in salt caverns and converting it into a power source could help meet the UK’s future peak energy and load-following demands. 

The proposal is put forward in the Energy Technologies Institute (ETI) report Hydrogen – The role of hydrogen storage in a clean responsive power system by carbon capture and storage (CCS) strategy manager Den Gammer.

This uses findings from a techno-economic study carried out by Amec Foster Wheeler into the technologies used in hydrogen production, the stores themselves and the power sector that converts hydrogen into electricity.

It concluded that using salt caverns to store hydrogen for power generation when the demand for electricity peaks would reduce the investment needed in new clean power station capacity.

“We discovered that the ability to store hydrogen in large quantities and convert that hydrogen into power is a reliable, affordable and flexible way of creating power to meet peak energy demands in the UK,” Gammer said in a statement.

“The UK’s energy landscape is changing very rapidly. More renewable power supplies are being installed and, although clean, these new supplies are intermittent, which increases the need for a low-cost, clean, on-demand power supply that currently only fossil fuel plants can provide.

“The country needs a system that follows the load the public creates and our research shows that systems involving the storage of hydrogen, and creating power from it, can do that in a very flexible way.”

Modelling showed that such schemes would become effective in 2030–2040, Gammer said.

“The main benefit is one of cost, as it would be a low-cost way of providing clean power for peak and load-following demand,” he added. “Large amounts of energy can be stored, with one cavern providing enough storage capacity to satisfy the peak demands of a single UK city.”

Salt caverns are already used for storing oil and natural gas. There are about 30 very large caverns in the UK.

The ETI believes fossil fuels will still have a role to play in the UK’s energy system beyond 2030 but says the plants should be equipped with CCS technology. It also believes that building a 10GW-scale CCS sector in the UK by 2030 is feasible and affordable.

Apart from providing low-carbon electricity, CCS can capture emissions from industry, help deliver low-carbon gas and deliver ‘negative emissions’ when combined with bio-energy.

“Beyond 2030, to get the most out of the investment required for installing a CCS plant you would need to reduce the time it is spent idle because its power production may not be required,” Gammer said.

“If you can store hydrogen that is produced continuously by modestly sized hydrogen plants in salt caverns, then you release that to generate electricity only when the system demands it.”

A recently published ETI report, Insight Infrastructure and Investments – Preparing the UK for the Energy Transition, concluded that the UK can implement an affordable transition to a low-carbon energy system over the next 35 years by developing, commercialising and integrating technologies and solutions that are already known but are underdeveloped.

The report also said that decisions taken in the next decade are critical in preparing for the transition.