SGHC is a pioneering project, being one of the UK’s oldest and largest commercially developed city centre district energy schemes. ENGIE has grown the scheme through new connections across a diverse range of customers and installing additional energy centres. Over last 10 years the energy supply has grown by over 50%, original contracts have been renewed and the agreement with Southampton extended.

In 1986, the scheme began delivering heat from the geothermal borehole through a district heating network. Over the years, the main heat station has added several combined heat and power (CHP) engines (6.7MWe) and back-up boilers (8.0MW) for heating along with absorption chillers and back-up vapour compression machines for cooling (13.1MW) and now has a total of five energy centres across the city feeding into the networks.

The scheme, which started with a single customer (the Civic Centre) now has thousands of customers supplied via heat network and five energy centres to ensure a 24-hour heat supply. It provides heating and cooling to over 2,500 residential customers (apartments and student accommodation), several large office buildings, a hospital, a university , a large shopping centre with multiple outlets and department stores, a supermarket, several hotels (666 beds from luxury to budget), BBC television studios, a swimming and diving complex and the main city police station, among others.

The original heat station established in 1986 on land adjacent to the Pirelli General Cable Works was on open land surrounded by stacked containers. 10 years ago the Pirelli Works had been replaced by a retail park, including an Ikea store which is both a heat and chilled water customer. The energy centre has also had an extension. At the northern extent of the heat network is the Royal South Hampshire (RSH) Hospital. A 725kWe CHP engine and boilers supply the hospital with its heat and electricity, as well as pumping heat into the network to supply other nearby customers, such as the Liberty Point student accommodation and Southampton Solent University campus.

Between the heat station and the RSH Hospital is the Civic Centre, where SGHC maintains and operates the council boilers as a further heat supply for top-up and standby. The City of Southampton continues to grow and develop and the Southampton networks similarly grow, with opportunities for energy centre expansion, new connections and, as a mature scheme, contract renewals. The scheme is therefore continuing to deliver low carbon, competitive, secure energy to the City and diverse range of customers.

History of the scheme

In the early 1980s, as part of the city's plan to become self-sustaining in energy, the council (led by Alan Whitehead, now the MP for Southampton Test) took advantage of a geothermal borehole commissioned by the Department of Energy, to examine the potential of geothermal heating in the UK. Due to insufficient resources in the geothermal aquifer, the Department of Energy decided not to proceed but Southampton took the decision to pioneer district heating, and carried on after entering into a ground breaking co-operation arrangement with Utilicom Ltd (now ENGIE.)

In 1986, Southampton began pumping heat from the geothermal borehole through a district heating network. Over the years, several combined heat and power (CHP) engines and backup boilers for heating have been added, along with absorption chillers and backup vapour compression machines for cooling.