The Prince of Wales will open the innovative plant at The Rainbarrow Farm in Martinstown - which will also include a Biomethane-to-Grid Plant. The digester is owned and run by JV Energen - a joint venture between local farmers and the Duchy of Cornwall.
The plant will provide renewable gas directly to the local community in Poundbury - and could supply up to 56,000 new-build homes in the summer with renewable gas.
Simon Conibear, Dorchester Estate Director for the Duchy of Cornwall, said: "This project is a major milestone for Poundbury, Dorchester and the Duchy of Cornwall and for the UK renewable energy industry.
"It is the result of exemplary collaboration with local farmers and producers of waste, and it will provide a substantial amount of renewable electricity and gas to houses and businesses on the development and further afield."
Anaerobic Digestion is a natural process where without oxygen, organic material such as food is broken down by micro-organisms to produce bio-gas which is rich in methane.
Rainbarrow Farm will use around 41,000 tonnes of maize, grass silage and food waste each year, sourced from local businesses including Dorset Cereals and the House of Dorchester Chocolate Factory.
Local farmer and member of JV Energen Nick Finding said: "Growing maize for the Anaerobic Digestion plant means we can produce much more energy per acre and we no longer have to send crops abroad to convert into bio-diesel.
"Growing energy crops is an important additional income stream for local farmers like me."
Anaerobic Digestion produces a bi-product called digestate - which can be used as an organic fertiliser on crops.
Rainbarrow Farm sits on Duchy of Cornwall land just outside of Poundbury. As well as providing environmentally waste disposal and reducing the amount of waste, the plant will save around 4,435 tonnes of CO2 emissions every year.
