GE Vernova modernizes UK combined-cycle gas power plant

In the power generation and energy infrastructure sector, GE Vernova has completed a major modernization project at InterGen’s 800-MW combined-cycle Coryton Power Plant in the United Kingdom, demonstrating how advanced gas turbine upgrades can improve efficiency, flexibility and emissions performance in existing thermal assets.

The project involved a major outage and the installation of High Efficiency (HE) upgrades on two GT26 gas turbines at the Coryton site, located east of London along the River Thames. Following commissioning, plant performance exceeded initial expectations in both power output and efficiency, reinforcing the role of modernized gas-fired generation in supporting grid stability alongside growing renewable capacity.

Higher output and improved thermal efficiency
The HE upgrade applied at Coryton integrates advances in gas turbine aerodynamics, compressor design and combustor technology. As a result, the upgraded units delivered up to 85 MW of additional power, surpassing the originally expected 77 MW increase. Unit efficiency improved by 2.46%, enabling the plant to generate the same electrical output while consuming less fuel.

From an operational standpoint, higher efficiency translates directly into lower operating costs and reduced fuel demand, while also contributing to longer maintenance intervals for critical components.

Measured emissions reduction through fuel savings
By improving efficiency and output without increasing fuel input, the modernization is projected to reduce emissions by approximately 67,500 tonnes of CO₂-equivalent per year, assuming unchanged annual electricity production and around 6,500 operating hours. The reduction results from lower fuel consumption per kilowatt-hour generated rather than from fuel switching.

This performance aligns with UK and European energy policies that emphasize decarbonisation through efficiency improvements, particularly in flexible gas generation assets that support intermittent renewable sources.

Comprehensive outage and large-scale execution
Beyond the turbine upgrades, the outage scope included borescope inspections of generators and steam turbines, valve inspections and full electrical testing across the plant. More than 300 specialists from GE Vernova’s global engineering, manufacturing, logistics and field services teams were involved in the execution.

The project was completed after over 122,000 working hours with no recordable environmental, health or safety incidents, highlighting the complexity and scale of the intervention on an operational combined-cycle facility.

GT26 platform modernization and future fuel flexibility
The Coryton project forms part of GE Vernova’s broader GT26 modernization program, which was introduced in 2019 and combines design elements derived from both F- and H-class gas turbine technologies. The HE upgrade incorporates additive-manufactured components, advanced materials and combustion dynamics, enabling higher output and efficiency without changing the plant’s fundamental architecture.

GT26 gas turbines are designed to operate on a range of fuels, including natural gas and hydrogen-natural gas blends, providing operators with options to further reduce emissions as fuel infrastructure evolves. As of 2025, eleven GT26 units worldwide are operating with the HE upgrade in service.

www.gevernova.com