29 JAN 2024

InterGen's power stations: their history, and their future

InterGen is one of the longest operating independent energy generators in the UK, with over 25 years’ experience in energy markets.

We operate four power plants across the UK, with a generating capacity of over 2,800 MWs. We are proud to provide power to over 2 million homes across the UK and employ nearly 120 people at our sites.

Below, we share some information about each of our power stations, their history and their future.


Located just 30 miles east of London, next to the London Gateway Port, sits our Coryton plant – a natural gas fired CCGT plant with a capacity of 800MW. In one of the largest UK infrastructure projects in the last decade, the plant recently commissioned a private wire connection to the port, capable of delivering 75MW of power.

Coryton’s roots go back over a century, with the station occupying the site of a former munitions factory dating back to 1895. The plant has now been operating for over 20 years and powers 800,000 homes across the south of England.

InterGen are also investing in an upgrade to Coryton’s HE technology which will increase its efficiency, reduce carbon emissions and allow it to take advantage of a blended hydrogen stream as and when available.


As our first generating asset in the UK, Rocksavage holds a special place in the InterGen story. The plant was opened by Her Late Majesty Queen Elizabeth II in 1998.

Located in Cheshire near Runcorn, at the junction of the River Weaver and River Mersey, its name came from a now-ruined Elizabethan mansion ‘Rocksavage’. This mansion also had royal connections, and was visited by King James I in the 17th Century.

A combined cycle natural gas fired power plant, Rocksavage powers over 800,000 homes, and has a capacity of 810 MW.

We are now looking to the future and plan to bring hydrogen to Rocksavage in conjunction with the HyNet project and we achieved an efficiency improvement of 1% in 2022 following a £1.2m investment to upgrading our technology.


Spalding, another combined cycle gas plant, celebrates its 20th anniversary this year. It recently enjoyed a significant upgrade to Advanced Gas Path Technology in 2018.

Located in Lincolnshire on a former British Sugar site, the station is currently able to export 950MW - with plans for further increase – and powers over one million homes.

Linked to the plant is the Spalding Energy Expansion, an open cycle gas turbine plant (OCGT) capable of producing 300MW.

Beginning commercial operations in 2019, the plant provides essential back up for renewable sources of generation such as wind and solar and was constructed in partnership with Siemens, Atlantic Projects Company and Darke Engineering.


For all of our sites, we recognise the need to meet net zero and move towards flexible generation. We are not only a key delivery partner in the just transition away from gas, but we are also investing significantly in adopting new technologies too.

In addition to developing our leading 900MWh Gateway battery storage project, we have a pipeline of five further large-scale battery storage projects representing 2.5GW of flexible supply. As mentioned previously, we are also investing in a major upgrade at Coryton, and our work with the HyNet project will bring hydrogen to Rocksavage.

All of our plants are also active in supporting their local communities. From the purchasing of new defibrillators units to developing close links with colleges and training centres are providing opportunities for local young people, we know the importance of being good neighbours.