The re-fitting of one of London’s lesser-known power plants is set to provide a big boost for the city’s future heat and energy requirements.

E.ON have just completed a three-year, £26m refit of the Citigen combined heat and power plant beside Smithfield market, making it the largest such plant in the UK.
Citigen combined heat and power plant
E.ON has owned the plant, located at the Port of London Authority and the Central Cold Store since 2002, and it produces enough power for 11,300 homes and heat for buildings in the City of London via a district heating network. It also provides chilled water, which is used for district cooling in several properties’ air conditioning systems.

The Guardian reports that the upgrade to the facility entailed replacing two unreliable and dirty ship engines with smaller, cleaner gas versions at the start of 2017.

In the process, it has signed up new customers such as Blake Tower, a recently refurbished block of flats and Barts Square, a mixed residential-commercial development – the first new connections to the heat network for a decade.

John Armstrong, who heads E.ON’s decentralised energy unit, said: “The company previously didn’t necessarily know what to do with it [Citigen], but now we’ve invested heavily in it and recognise its importance in the heart of the city. The new connections show that there’s a demand for lower carbon heating and chill.”

The central location and listed buildings made the upgrade a challenge. The roof was taken off and a tower crane used to pluck out the enormous old engines and vast tank holding the 1m tonnes of diesel that powered them.

Above ground sits a new control room that now not only runs the power station beneath it but manages the 60 other district heating schemes that E.ON owns around the UK.

The new plant comprises two gas engines, heat recovery equipment, a 50-metre tall thermal store (effectively a big hot water tank), and the chilling machines.

Water is heated to 105C-110C in the thermal store, before being piped out to the 17 connections served by the plant.

The facility produces three times as much heat as it does chill, but the demand for cooling is growing faster, said Armstrong. From Smithfield, the network spiders out underground for 4 miles of heating and 2.7 miles of chill, taking in Guildhall to the south-east and the Barbican Centre to the east.

District heat networks in the UK supply around the country’s heating demand, but the government believes this could reach by 10 per cent by 2030 and have allocated £320m to funding the networks over the five years.