Reducing energy costs and CO2 for Southern Water - Bexhill, Ford and Sandown
Routed through a sewer network of 39,000km, 730 million litres of wastewater get treated and recycled at the company's 368 treatment works daily.
Southern Water set an objective of reducing carbon emissions and expanding energy efficiency schemes between 2010 and 2015. These would enable the company to generate 20% of its energy from renewable sources by 2020. Efficient generation is important to support the water supply infrastructure and service to water customers.
Through biogas-fuelled combined heat and power (CHP) technology, Veolia has been able to use renewable power from sewage treatment to generate electricity for Southern Water at its Bexhill, Ford and Sandown wastewater treatment works. The £2.5m biogas CHP plants were delivered by Veolia's specialist CHP team (Cogenco) and bring Southern Water a step closer to generating 20% of its energy from renewable sources by 2020.
The project included the design, build and supply of the biogas CHP units by Veolia. The CHP plants use biogas, which is created during the wastewater and sewage treatment processes through anaerobic digestion. This biogas becomes the fuel source for the CHP engines that provide power and heat to the works, with any surplus electricity exported to the National Grid.
While the biogas is used to generate electricity, the 772 kWe CHP plants at Bexhill and Ford, and the 360kWe at Sandown, also recover heat from the engine and exhaust systems through water from heat exchangers. The hot water then serves to heat the treatment tanks and thus helps to speed up the bacterial digestion of organic matter. This process efficiently increases waste digestion.
CHPs provide electricity and heat from a single fuel source and are more than twice as efficient as conventional power stations. The result is cost savings, greatly reduced emissions and improved carbon footprint, independent electricity supply with better energy stability and therefore less exposure to electricity price fluctuations.
The CHP units will help to reduce energy costs and save 7,500 tonnes of CO2 each year across the three sites in line with Southern Water's environmental policy. Southern Water benefit from the biogas CHP design, installation and operation expertise from Veolia's teams who support this site applications on a 24/7 basis. The installations provide renewable energy from the waste water treated on the sites.
“Harnessing recoverable energy through the use of CHP plants is just one of the innovative ways Southern Water is helping reduce its impact on the environment by reducing our carbon footprint while also cutting our energy costs”
Southern Water Project Manager