National Grid goes carbon-free with hydrogen-powered substation trial

  • Hydrogen powered unit (HPU) quietly provided carbon-free electricity to National Grid’s Deeside Centre for Innovation
  • Only emission is water
  • HPUs could save an estimated 500,000 kg of carbon across all National Grid substation sites

National Grid has completed a ten-week trial to test a hydrogen-powered generator at its Deeside Centre for Innovation (DCI), a state-of-the-art testing facility hosting a 400 kV modified substation, designed as a unique environment for development and trial of innovative technologies and practices.

A GeoPura 250kW hydrogen power unit (HPU) contained within a transportable shipping container measuring 7.2 m by 2.5 m was installed at DCI and produced the energy to power low-voltage equipment needed for National Grid’s innovation testing projects and site operations. The trial tested the capabilities and feasibility of HPUs as direct replacements for backup diesel generators across more than 250 National Grid substation sites, the data will now be analysed and shared later this year.

National Grid currently use diesel generators alongside batteries to provide backup power to a substation for key activities such as cooling fans, pumps, and lighting, enabling it to continue to perform its crucial role in the electricity transmission system.

These backup generators are rarely used and have less than a 1% chance of operating per year, however, on the rare occasion that backup power is required, changing from diesel to low-carbon emission alternatives have the potential to reduce carbon intensity by 90%* and save over 500,000 kg of carbon emissions.

The HPU at Deeside has power capabilities of up to 100 kW in continuous operation mode and up to 250 kW for 45 minutes and uses 100% green hydrogen. The unit is quieter and the hydrogen cannisters used to fuel the generators can be safely stored on site.

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.

Prem Ranjan, Test Engineer at Deeside Centre for Innovation said: “The HPU has been tested for different load profiles including typical critical substation equipment. The trial results for electrical performance and environmental aspects along with hydrogen management at our substations will now be examined as viable zero-emission alternatives to diesel backup generators.”

Sean Coleman Manager for Deeside Centre for Innovation said: “We are delighted to have trialled this innovative off-grid power source at National Grid’s Deeside Centre for Innovation. 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.”

Andrew Cunningham, Managing Director at GeoPura said:” Backup power plays a critical role in the UK's electricity transmission system, and this is a fantastic example of how hydrogen can be used to eliminate harmful environmental emissions in the event of a primary power loss. We are thrilled to have supported National Grid to undertake this comprehensive testing programme, providing a reliable, critically backed, zero-emission alternative to high polluting diesel generators.”

Visit Deeside Centre for Innovation for more information.


*Emissions calculations are based on an estimated 66 diesel fuelled engines used for black start recovery on the electricity transmission network in England and Wales. Assuming the diesel engines have the minimum emission control devices, the EU carbon intensity values for class 2A diesel used in an engine is 977 g/kWh. Hydrogen produced via electrolysis is 82g/kWh. It's assumed that one alternative, a hydrogen powered fuel cell could return the quoted figures under the proposed new electricity restoration standards.