How much power does an AD plant produce?
Anaerobic digestion plants come in different sizes, and are described by their engine capacity and the type of inputs, or 'feedstock', used.
For example, 1 MW AD plant has an engine which generates 1000 kW every hour. This equates to 8760000 kWh per year.
OFGEM cite the typical (median) domestic household electricity usage per year as 3,300 kWh.
An AD plant uses some of the power produced in its own operation, and there will be some capacity and efficiency variations across a year, so we use an estimate of around 2,000 households' electricity supply per MW capacity.
The Centre for Sustainable Energy website shows the typical power rating of various household appliances. A typical oven uses 2kW, so a 1 MW AD plant could supply enough electricity per hour for 500 ovens.
What is the net electrical yield of food waste?
The UK government has estimated that the net electrical yield of food waste is approximately 200kWh/tonne.
How much does a cubic metre of food waste weigh?
It’s difficult to put a weight to cubic metre capacity as it depends on the type of food waste.
For example, a caddy filled with bread crusts would weigh much less than one filled densely with wet tea bags. The nearest DEFRA conversion factor for waste category “Vegetable matter including food and bark” (22.06.00) is 0.75 tonnes per cubic metre, but this is not a direct like-for-like comparison.
Find out what happens in an AD plant here.