Greenfinch carried out pilot scale digestion trials on maize, grass, and fodder beet in 0.5m 3 stainless steel digesters.   The digesters were mixed semi-continuously using biogas mixing, and heated to 42 o C.   The digesters were fed daily (7 days per week) and discharged from regularly throughout the week.   The biogas was collected in a bell over water gas holder at the back of the digester and measured through a gas flow metre.   The feedstock was purchased from a local farmer on a weekly basis to ensure a constant quality of feedstock.   Gas production has been as expected for all feedstocks, but more importantly Greenfinch has learnt a tremendous amount about the detailed design required for digesting energy crops, specifically regarding soil, stones and grit build-up.  

Over a period of 15 months Greenfinch fed an 18m 3 digester a mixture of energy crops, whey and glycerine.   The energy crops were seasonal, using freshly mown grass during the summer months, and ensiled maize from a local farmer in the winter months.   The mean gas production was 25.3m 3 biogas per day.