The Bolivar Wastewater Treatment Plant (WWTP) is the largest wastewater treatment plant in the Adelaide region, and processes almost 70 per cent of Adelaide’s metropolitan wastewater.
The South Australian Government has approved a $25.8 million project for SA Water to optimise the energy utilisation on the site. This project will provide a major upgrade to the WWTP power supply by the installation of onsite electricity generation fuelled with the digester gas produced during the treatment plant process.
Clarke Energy Australia, one of the short listed tenderers, was awarded the contract to design and construct a fully operational turn-key gas to power the cogeneration plan. The design will utilise GE Jenbacher gas engines to fully integrate the electricity generated into the existing electrical infrastructure.
Clarke Energy’s cogeneration power plant design provides three GE Jenbacher high electrical efficient dual-fuel gas engines installed inside of the existing power house, each producing 2.4MWe.
The gas engines operate solely on digester gas or a blended mix with natural gas during times of low digester gas production. The gas engines also produce hot water to supply the heat to the plant digesters that is necessary to sustain the treatment process.
The low carbon emission electricity generated will result in a significant reduction in site greenhouse gas emissions of more than 11,000 tonnes per annum which is equivalent to reducing 2200 motor vehicles on the road.
The project is due to be commissioned in July 2013, and will be handed over to the facility’s operations and maintenance alliance contractor Allwater. Once completed, the plant will generate up to 85 per cent of the plant’s annual electricity demand. It’s hoped this will lead to annual electricity savings of $1.3 million with a capital payback period estimated at eight years.
Additionally, electricity market revenue of $0.7 million per annum will be earned and approximately $0.9 million worth of additional Renewable Energy Certificates will be created each year.