Optimising energy at wastewater plant in South Australia

The Bolivar Wastewater Treatment Plant (WWTP) is claimed to be the largest wastewater treatment plant in the Adelaide region, processing almost 70% 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 on-site electricity generation fuelled with the digester gas produced during the treatment plant process.  The reduction of greenhouse gas emissions and support for renewable energy projects are aligned with the state’s strategic plan.

Clarke Energy Australia was awarded the contract to design and construct the turnkey gas to power cogeneration plant using GE Jenbacher gas engines and 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 the existing power house, each producing 2.4 MWe. The gas engines will operate either solely on digester gas or a blended mix with natural gas during times of low digester gas production. The gas engines will 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.

The project is due to be commissioned in July 2013 and handed over to the facility’s operations and maintenance alliance contractor, Allwater. Once completed, the plant will generate up to 85% of the plant’s annual electricity demand. This means annual electricity savings of $1.3 million with a capital payback period estimated at eight years. Additionally, it is estimated electricity market revenue of $0.7 million per annum will be earned and approximately $0.9 million worth of additional Renewable Energy Certificates (RECs) will be created.

Clarke Energy’s Managing Director, Greg Columbus, said: “As a local South Australian-based business, we are proud to be working with SA Water bringing some international knowledge and class-leading technology to South Australia for this Bolivar project. Projects such as this typify the added value Clarke Energy brings to the GE Jenbacher product ensuring a sustainable long-term solution for our customers long after the installation is completed.”