Counting on … day 82

11th June 2025

Biogas is a mixture of methane, CO2 and other gases produced from plant and/or animal material via anaerobic digestion. It comprises between 45-75% methane by volume. Biogas can be used for cooking, heating and for electricity in biogas adapted power stations. Biogas can not as a direct substitute for natural gas. Biomethane on the other hand is nearly 100% methane and can be used to replace natural gas without changing the means of transmission or the end-user’s equipment.(1)

Biomethane is produced by upgrading biogas (ie removing the other gases by various means). Carbon dioxide produced as a byproduct can be used for industrial processes or combined with hydrogen to create more methane. At present biomethane represents about 0.1% of natural gas demand. (1)

The biomaterial used to produce both biogas and biomethane comes from the same sources as for SAF – ie waste material from farms and forestry work, solid municipal/ household waste (including food waste and packaging), recycled cooking fat ( I think MacDonald’s trucks advertise this), animal fat, virgin corn/soy/rapeseed/palm oil, sugar cane and beet,  aide and other grains, grasses such as miscanthus, algae etc – and therefore has the same issues around the sufficiency of supply. 

Should agricultural land be used to grow crops for provide biofuels or to provide food?

National Grid notes that “UK households, hospitality and food service, food manufacture, retail and wholesale sectors produce around 10 million tonnes of food waste per year. If this was all treated through anaerobic digestion, the industry could generate 11 TWh of biogas – enough to heat 830,000 homes – and cut emissions by 8.8 million tonnes of CO2 equivalent, or 2% of the UK’s annual emissions.” (2) On the other hand, as 70% of that food waste was edible, would it have been better used feeding people? Equally given that it represents £22billion (3) would it not be better if the waste been avoided in the first place and the money used for home insulation or public transport?

1. https://www.iea.org/reports/outlook-for-biogas-and-biomethane-prospects-for-organic-growth/an-introduction-to-biogas-and-biomethane

(2) https://www.nationalgrid.com/stories/energy-explained/what-is-biogas

(3) https://www.wrap.ngo/taking-action/food-drink/actions/action-on-food-waste