Decarbonisation Whisky Distilleries
Biogas + CHP Result
Assumptions:
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The sight will install an anaerobic digestion plant as well as a combined heat and power plant.
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Biogas produced from the whisky waste through the same AD plant will now be used to fuel a combine heat and power (CHP) plant instead of a biogas boiler.
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The electricity and heating conversion efficiency of the CHP plant is 35% and 45% respectively [1].
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Current cost of selling electricity to the grid is 7.64 p/kWh [11].
Results
Heat produced from the CHP plant meets 42% of process heating requirement. Electricity produced from the CHP plant meets 100% of the electricity demand. Additionally, CHP Plant is capable of producing 3.76 times surplus electricity which can be sold to the electricity grid.
​Overall reduction of 76% in process heating CO2 emissions can be achieved not only by replacing the natural gas and electricity from the grid but also by contributing renewable power in the grid electricity.
CAPEX of £3.1 million is required to install AD of 65 m3/hr rating and CHP equipment of 140 KW. Despite an overall positive yearly cash flow which includes savings on natural gas, savings by selling electricity and operational costs of AD and CHP plants, the net present value of the project is – £1.3 million making it economically infeasible.
Sensitivity Analysis
One of the key factors to make a strong case for the installation of AD and CHP plant is the renewable electricity selling price to the national grid. Currently biogas electricity is purchased at very low rate by the government [11]. Based on 2022 economic parameters; the net present value of this project can be positive if the electricity selling price to the national grid is at least 19 p/kWh.
