If we take the most conservative of these forecasts, using only waste feedstock, then we can see that the total potential for AD in the UK is around 8 TWh of biogas, or 8,000,000 MWh. Based on these figures, current UK capacity is a tiny fraction of the theoretical maximum.

Biogas is most commonly also known as biomethane. It's also sometimes called marsh gas, sewer gas, compost gas and swamp gas in the US. Biogas is a naturally occurring and renewable source of energy, resulting from the breakdown of organic matter.

If upgrades to the local network are involved, this may require NIE to obtain planning permission which may add a time delay to the process. Biogas can be upgraded to biomethane and injected into a gas grid. This can be the national high pressure gas transmission grid or a local low pressure gas distribution network.

Biogas contains roughly 50-70 percent methane, 30-40 percent carbon dioxide, and trace amounts of other gases. The liquid and solid digested material, called digestate, is frequently used as a soil amendment. Some organic wastes are more difficult to break down in a digester than others.