HyScale: How we can exploit curtailed renewable wind power

Every year, British energy customers pay wind turbine operators not to receive their power – when the wind blows but there isn’t demand to meet it. An Ofgem funded project led by SSE with National Grid ESO recently concluded that unused wind generation could be deployed for domestic heating in Scotland by 2030, saving £24m per year in wind constraint payments (The 4D Heat project). However, a new consortium led by gas network operator SGN could further change the balance in favour of customers.

HyScale is an innovative project that aims to access curtailed wind generation to create green hydrogen as a storage medium for renewable energy. Working with partners Cadent, National Grid Gas Transmission and Wales & West Utilities, HyScale is investigating opportunities to use Liquid Organic Hydrogen Carriers (LOHCs) to capture, store, transport and release hydrogen at bulk scale around the UK.

Hydrogen would be produced using electrolysis powered by renewable wind and then hydrogenated – stored within a suitable liquid carrier.  The hydrogen, as LOHC, can be stored and transported in low cost containers and tankers and has the potential to be used as bulk storage underground without any degradation. When required for use the hydrogen is dehydrogenated from the liquid carrier and piped into a distribution network under pressure, in the same way natural gas is distributed today.

Hydrogen stored within a liquid is a potential carbon free solution to the problem of mass storage and transportation of electricity, for use at periods of high demand when the power grids are at capacity, or when customers can’t access energy where they need it. It has significant advantages over compressed hydrogen gas, not least its easy storage and portability. 

It would provide an alternative to storing energy in expensive high-risk pressurised steel vessels as LOCHs can be stored at normal atmospheric pressure. Hydrogen in a LOHC state can be stored and transporter in the same way as liquid fuels such as diesel, but at less risks due to the very low volatility of LOHCs.

One of the key advantages of LOHCs verses compressed hydrogen is that it has a much higher energy storage density. A compressed hydrogen storage vessel operating at 100 bar provides 8kg/m3, whereas a LOHC such as DBT (dibenzyltoluene) at atmospheric pressure can provide 54kg/m3 of hydrogen. This seven-times multiple has the potential to make storage and transport of hydrogen using LOHC much more attractive and economically viable in the future.

So LOHC is a safe, zero carbon energy storage solution that could re-purpose existing storage and transportation infrastructure currently being utilised by diesel and petrol fuels. Its familiarity as a liquid makes it compatible with existing logistics operations handling diesel and petrol, making a future market for LOHC a real possibility.  It can aid the transition away from off-grid solid fuel and oil users, support the distribution of hydrogen to remote refuelling stations and potentially provide additional storage solutions for future hydrogen gas networks.

HyScale’s first phase of development is expected to conclude in March 2021, with the hope that a trial build will commence soon after that would provide the evidence base to support larger scale development.