The facility uses well-established mass-burn incineration technology for the
combustion of 420,000 tonnes of municipal solid waste a year. This waste, which comprises
domestic waste from about 400,000 homes together with commercial waste from local
businesses, is delivered by road to the plant. The raw waste is deposited into a
totally enclosed tipping hall capable of storing up to four days' supply for the plant,
sufficient to cover weekends and extended holidays. Waste is fed by crane from the
storage bunker into one of the two identical incinerator streams, each capable of burning 29
tons per hour (tph). The two furnaces use Martin reverse-acting stoker grates to agitate
the waste during combustion, and energy recovery will be achieved via integral CNIM
three-pass membrane-wall boilers and economisers, nominally producing 152tph of
superheated steam at 47 bar 395°C. The steam fed to a single medium-pressure
steam turbine driving a four pole synchronous 31MW alternator with automatic regulators
at a nominal 11kV. Exhaust steam from the turbine is condensed by means of air-
cooled condensers. This full system redundancy gives operating flexibility in the event of a
shutdown of one system, and enhances the reliability of the 24 hours a day, 7 days a week
operation. Plant availability is expected to be greater than 85%.
SELCHP also has plans to sell excess heat left after electricity generation to over 7,500 homes and local schools in the London Borough of Southwark via a district heating system. Implementation of this part of the project has been postponed until the Non-Fossil Fuel Obligation (NFFO) contract has expired, but when constructed, over 6km of double- insulated underground pipes will be used to connect the plant to both new and existing heating networks via heat exchangers. Use of the heat from SELCHP will avoid the need to run the six fossil-fueled boiler plant which currently provide heat to the homes. These boiler plant will be retained, however, to provide heat when SELCHP is closed for maintenance or as a top-up during especially cold periods when heat demand is high.
To minimize pollution, SELCHP uses carefully controlled high temperature combustion and advanced flue gas cleaning equipment, including acid-gas scrubbers and bag filters to remove particles and dust. The plant has received authorization from Her Majesty's Inspectorate of Pollution (HMIP) under the stringent standards imposed by HMIP IPR 5/3.