Wiseman is by no means alone in looking at ways to save money while becoming more "green" in its business. A number of other companies are investing in technology intended in one way or another to reduce fossil fuel usage.

This month Diageo, the international drinks group, announced a plan to invest £65m in a "bioenergy facility" at its distillery in Cameronbridge, in Fife. Diageo has yet to gain planning approval but the intention is that the facility will combine an anaerobic digester and a biomass boiler. The digester will capture the methane gas - a powerful greenhouse gas - produced by decomposing organic matter such as wheat, barley and yeast from the distillery. Then the biomass boiler will use the dried solids from the digester as a fuel.