BIOGAS
"In Southeast Asia, with its large agriculture sector, no other source of renewable energy comes close to biogas in terms of contribution to the Sustainable Development Goals."
Des Godson, CEO
What is biogas?
Biogas is produced when organic matter decomposes in an anaerobic environment (without oxygen). It is a mixture of methane (CH4) and carbon dioxide (CO2) with trace elements of other gases including hydrogen sulphide (H2S).
A biogas system is best described as a giant anaerobic microbiome consisting of diverse groups of bacteria as well as their ancient cousins – archaea. Billions of anaerobic microorganisms work to break down organic material into simpler and simpler molecules until eventually the methanogens produce methane gas.
A skilled operator feeds the biogas digester with organic waste and controls the temperature and acidity levels. The aim is to maintain consistent gas quality, maximising methane production and minimising hydrogen sulphide.
Raw biogas is saturated and water vapour and H2S must be removed to acceptable levels for the intended final application: boiler fuel or power generation. Where the gas is used for transport fuel or for injection into a natural gas pipeline it needs further upgrading.
waste sources
In Southeast Asia agricultural and agro-industrial waste is an abundant and excellent organic substrate for biogas production. Every tonne of palm oil generates 3-4 tonnes of palm oil mill effluent and 1 tonne of empty fruit bunch. Every tonne of cassava starch generates 19 tonnes of process wastewater and other solid wastes. Asia Biogas has many years of experience producing biogas from agricultural waste from the cassava and palm oil industries.
Biogas produced directly from food and energy crops such as maize is known as a ‘first generation‘ biofuel. The biogas we produce in Southeast Asia is almost always a ‘second generation‘ biofuel, produced from waste. This premium product has much more positive environmental and social impacts.
Biogas systems
There are many types of biogas system including in-ground “covered lagoon” and “tank based” systems. Each one has strengths and weaknesses. In Southeast Asia, due to the high ambient temperatures and the remote location of most projects, covered lagoon systems are generally the best technical and economic solution. There are many types of covered lagoon biogas systems. Most important is that the design is suitable for the type of substrate to be digested.
Asia Biogas has gained a wealth of experience in the construction and operation of cost-effective and reliable covered lagoon biogas systems. Our focus is to maximise biogas production. Our design team and directors also have experience in designing and commissioning tank-based solutions. We are pleased to share this knowledge with our clients.
what is biomethane?
Biomethane is produced by removing CO2 and impurities from biogas using a variety of proven gas separation processes. This high value source of renewable energy offers a climate friendly way to replace fossil fuel natural gas. Its high methane concentration, usually 85-95%, is matched to the natural gas specification in each country. Biomethane is often referred to as ‘green gas’ or ‘renewable natural gas’ because it is 100% renewable.
Biomethane may be sold as vehicle fuel or injected to natural gas pipelines. Compressed Biomethane Gas (CBG) is a direct substitute for Compressed Natural Gas (CNG) which is sold as natural gas vehicle fuel (NGV) in Thailand. With its large agricultural sector, Southeast Asia has an enormous potential to supply biomethane but this requires active supports from government policymakers.