In late July, some local volunteers joined with local environmental group the Wasteless Society who organised a group visit to the Fre-Energy anaerobic digester (www.fre-energy.co.uk) near Wrexham. Hosted by its designer James Murcott, and
his colleague Angie Bywater, who gave us a fascinating explanation and guided
tour of the facility.
This is an on-farm digester, located on the largest organic dairy farm in Wales, with a
daily intake of 30 tonnes of cow slurry plus 6 tonnes of chicken litter a day
from a local broiler unit.
The outputs
are 160kW of electricity and 200kW heat, of which approx 30kW electricity is
used on site to power the adjoining engineering business, the Fre-energy
office, and a large 7 bedroom farmhouse. Approx 60kW of heat is used to heat
the cow slurry and chicken litter in the digester up to 40°C and the rest is
used to heat the house and office. The surplus of the electricity is exported
to the National Grid.
The digestate
produced, is then separated with the liquid being stored in a lagoon before
being spread onto the grassland using an umbilical cord through a spike
aerator. The solid digestate, which contains a higher proportion of the
phosphate and potash, is transported by road to land used for growing winter
crops to feed the dairy herd. Several allotment owners in the local village
have used this product and have been so impressed that the owners say they
could market it for a substantial sum.
The Fre-energy
digester was designed specifically to take farm and organic waste, such as
food, or as previously noted, by-products from intensive chicken production.
The owners do not agree with the principle of diverting the growing of crops to
fuel digesters, just to produce electricity, but rather believe that the use of
slurry and organic and food waste, is a key solution to many of the energy,
fertilisation and pollution challenges in farming and food production today.
A big thanks to Kate Evans who organised the fascinating trip which hopefully helps to raise awareness of this emerging green technology.
