National Grid posts success with hydrogen generator trial

The HPU was stored in a shipping container. Image: National Grid

The trial took ten weeks to complete and was hosted at National Grid’s Deeside Centre for Innovation in north Wales. The Centre is a testing facility, developed to enable 24/7 trials of innovative technologies and processes in an environment replicating a 400 kV substation.

During the trials, a 250kW hydrogen power unit (HPU) from GeoPura was used to power low-voltage equipment as well as site operations like cooling, pumps and lighting. The hydrogen to serve the generator was ‘green’, meaning that it was generated by running water through an electrolyser system served by renewable electricity.

National Grid was seeking to find out whether HPUs could be a feasible direct replacement for diesel backup generators, which are the chosen technology – along with battery energy storage – for providing emergency power at substation sites. National Grid operates more than 250 substations across the UK.

The trials confirmed that the HPU could provide up to 250kW for up to 45 minutes and up to 100kW for longer periods. They also revealed that the unit was considerably quieter than a diesel alternative.

While backup diesel generators are rarely used by National Grid, they are emissions-intensive when they are used. National Grid has stated that its diesel generator use generates more than 500,000 kg (500 tonnes) of carbon dioxide emissions each year.

Data resulting from the HPU trial will now be analysed. The results will be shared later this year, as well as decisions about any potential additional trials and rollout.

The manager of the Deeside Centre for Innovation, Dean Coleman, said his team is “delighted to have trialled this innovative off-grid power source”. He said: “The HPU powered our test facility 24 hours a day, seven days a week and we will now consider the findings, which we hope will help accelerate the transition to a flexible and low carbon future.”

HPU momentum

National Grid is aiming for net-zero by 2050, in line with the UK Government’s legally binding target. It is not the only organisation seeking a lower-emission alternative to diesel backup generators as the global net-zero transition builds momentum. Last year, Microsoft completed trials of HPUs to replace diesel backup generators at data centres, completing a pilot in Latham, New York.

Also using hydrogen generators is construction firm Mace Group.

Microsoft concluded that the large-scale adoption of hydrogen fuel cells should only be attempted once green hydrogen is “widely available and economically viable”. Most global hydrogen production at present is ‘grey’ – reliant on fossil fuels. This means that, while the hydrogen produces no greenhouse gas emissions at the point of combustion, it is not a low or no-emission product across its lifecycle. It also means that grey hydrogen is currently far cheaper than green, but nations have collectively pledged to bring green hydrogen to price parity with fossil hydrogen by 2030 through the Breakthorugh Agenda.

As an alternative to diesel that is more commercially mature than HPUs, some firms, including Skanska, McAlpine, Interxion and Kao Data, are choosing generators fuelled by hydrogenated vegetable oil (HVO). However, others continue to invest in new diesel generators. Just this week, distribution company completed the acquisition of a diesel backup generator for its head office and distribution centre in Hatfield.

Related story: UK risks losing hydrogen innovation race, with EU and Japan pulling ahead, IEA reveals