Biogas is a mix of methane and other gasses generated from anaerobic digestion (microorganisms breaking down materials) of food, crop waste and manure. It requires large volumes of feedstock so it is most often generated alongside intensive operations with large waste streams, such as piggeries and diaries, or landfill sites. In some cases, a centralised plant with multiple waste streams and access to more capital may be a more cost-effective solution than on-farm biogas production.
Biogas can be combusted to generate electricity and heat. If biogas is purified to make biomethane (sometimes also referred to as renewable natural gas) by removing the carbon dioxide and other gases, the refined gas can be compressed and used to fuel vehicles or injected into the natural gas grid.
Biogas production can divert waste away from landfill, offer a secure and dispatchable source of energy and present an opportunity for regional economies to derive a source of income from waste products. In addition to producing fuel, other benefits of biogas production can include fertiliser production, reduced odour and emissions reduction. While combustion of biogas, like natural gas, produces carbon dioxide, because biogas is produced from plant matter that sequesters carbon from the atmosphere during its growth cycle, it can be a carbon-neutral source of energy. Also, the global warming potential of methane is more than 20 times higher than carbon dioxide, so capturing methane to produce biogas prevents that methane from venting into the atmosphere, resulting in lower emissions.
The Bundaberg bioHub, where the former Bundaberg East Wastewater Treatment Plant has been repurposed as a biomanufacturing precinct includes a biogas plant. For information about the Bundaberg bioHub, click the link for the Exploring Beyond Diesel 2 webinar to watch the recording and download the presentation of Utilitas CEO, Fiona Waterhouse.