Case Study - Reducing Reliance on Fossil Fuel
31 May 2012
Our Commitment: By 2020
we will ensure that 20% of the industry's primary energy
requirements will be derived from non-fossil fuel sources, with a
target of 80% by 2050, thereby reducing greenhouse gas emissions
from fossil fuel sources to a minimal level.
Distillation is energy-intensive but produces co-products which
can be used as a fuel source. Whisky-making results in two key
co-products. Draff is a residue, resulting from malted and unmalted
cereals soaking in warm water to remove the sugars as wort. Spent
wash or 'pot ale' is the residue in the still after fermentation
and distillation of the wort has taken place. Both have
traditionally been reused as animal feed products known as 'dark
grains' or as a fertiliser and soil improver.
The industry is investing in new ways to recover energy from
co-products as an alternative fuel to produce heat and power. This
will significantly reduce reliance on fossil fuels.
Work has started on a new £65m bio-energy facility at Diageo's
Cameronbridge distillery in Fife, believed to be the largest
investment in renewable energy technology by a non-utility company
in the UK. The facility will use a range of technologies, including
anaerobic digestion and biomass combustion to provide 98% of the
steam and 80% of the electrical power required to run the
Spent wash will be separated into a liquid and a solid fraction
using belt filter presses. The liquid will be subjected to
anaerobic digestion which produces biogas.
The solid fraction in combination with the biogas, will fuel a
combined heat and power plant. This will dramatically reduce
current gas requirements. Fossil fuel CO2 emissions are expected to
fall by 56,000 tonnes a year, and the need to transport 90,000
tonnes of draff offsite will be reduced.
The Combination of Rothes Distillers (CORD) is a consortium of
six distillers - Chivas Brothers, Glen Grant, Inver House, Diageo,
The Edrington Group and BenRiach. CORD is investing nearly £30m to
build a new Combined
Heat and Power (CHP) Plant to replace the existing dark grains
facility. This is the first project of its kind in the UK, using
draff and pot ale as a biomass source. The
investment in a centrifuge and membrane filtration plant will
generate over 7MW electricity. Excess energy will be sold to the
National Grid - enough to power 9000 homes.
The filtered liquid will be high in nutrients and be sold to
local farmers as an organic soil conditioner. The separated
dewatered solids will be used as a fuel source for the CHP plant.
Water usage will be reduced. It is expected that 47,000 tonnes of
CO2 will be saved each year, as well as the saving in transport of
animal feed to markets outside Speyside.
Work has now finished on Diageo's new £40m malt whisky
distillery at Roseisle in Moray. The plant has been built to the
BREEAM standard, which is recognised as best practice in
Roseisle employs anaerobic digestion to convert carbohydrates in
distillery co-products into methane and 'clean' water. The water is
used in the malting process,
whilst the methane is fed into a biomass boiler to reduce reliance
on fossil fuels. The distillery is sited next to Diageo's existing
Burghead maltings, which allows waste heat from distilling to be
diverted to the maltings plant, again minimising fossil fuel use
and CO2 emissions from raw material transport.
The combined technology offsets the distillery fossil fuel
demand by 85%, with half the power requirements coming from biomass
and biogas. This together with the heat recovery system will
recover 8.6Mw of the 10.2Mw demand.
As a prototype project, Scottish Bioenergy is building a reactor
at The Edrington Group's Glenturret distillery, near Crieff. CO2
from the distillery boiler will be captured by algae growing in
nutrient rich effluent. The biomass will be converted into oil
which can be used as fuel and proteins for animal and fish food.
The system has an added advantage in that the algae will remove
copper from the effluent.