The site
The Boral Biogas to Energy plant is at Boral’s Deer Park facility. It utilises biogas generated through the decomposition of organic materials in household waste at Boral’s Western Landfill, the group’s co-located landfill business. The facility began producing renewable energy and exporting green electricity in February 2006. A second module is currently being commissioned, and there are plans for up to ten modules.
Technology
Landfill Management Services (LMS) installed the biogas collection system, a network of wells drilled into the waste mass. Biogas is piped to the Biogas to Energy facility where it is used by a 1.1 MW Caterpillar 3516 reciprocating engine to produce renewable electricity, which is exported to the national electricity grid. Based on 50 per cent methane content, each generator module uses about 650 m3 of landfill gas per hour. Excess biogas is flared.
Article continues below…Energy purchase and supply
The first module installed is expected to export about 9,100 MWh per annum, increasing to 18,200 MWh per annum in October 2007 when the second module is commissioned. Power generated from the project is sold to Origin Energy under a long-term power purchase agreement. The plant operates on a 24-hour basis, contributing baseload for the national electricity grid. It is registered as a non-market, non-scheduled generator in the National Electricity Market, and is an accredited generator under the Mandatory Renewable Energy Target and NSW Greenhouse Gas Abatement schemes. Boral also proposes to seek accreditation for the second and future modules under the Victorian Renewable Energy Target scheme. The modules produce electricity at 415 V which is stepped up to 22 kV for the connection to the Powercor distribution network.
Environmental impact
Each module is expected to save 49,000 tonnes of greenhouse gases per annum (the equivalent of removing about 11,400 cars from the road), by utilising landfill gas that would otherwise escape into the atmosphere, and by offsetting fossil-fuel fired electricity generation.
Outlook
In mid-2007 the site had one generating module operating. A second 1.1 MW module, being built by contractor Energy Power Systems Australia (EPSA) at a further cost of $2 million, is expected to be operational by October 2007. Up to 11 MW total capacity is planned. Further modules are expected to be added every one to two years as biogas production increases, with plant export generation eventually reaching 73,000 MWh per year.
