UK distilleries and breweries are saving energy and reducing CO2 emissions by generating renewable energy from waste materials, via anaerobic digestion.
With very high electrical and thermal energy demands (and associated costs), distilleries are exploring ways of enhancing their energy efficiencies and improving their environmental performance. Increasingly, distilleries are investing in low carbon and renewable energy technologies, including renewable energy from waste.
The distillation industry produces large amounts of liquid and solid organic waste by-products (biowaste) which could be ideally used in the renewable energy process known as anaerobic digestion (AD). This can not only make distilleries energy self-sufficient and decrease waste management transport costs, it can also help them to meet their corporate social responsibilities, such as reducing their carbon footprint.
What is anaerobic digestion?
AD is a process in which organic feedstock in a heated digester tank is broken down by bacteria. In the absence of oxygen, the fermentation of the feedstock produces biogas – a methane-rich gas suitable for combustion.
How is biogas used?
Biogas can be used with a new efficient boiler; but the optimal use of this fuel is with a Combined Heat and Power (CHP) unit which generates on-site electricity and heat.
The benefits of using renewable energy from waste
The energy generated by the biogas CHP unit can be used in the distillery’s production facility, effectively displacing energy purchased from the national electricity and gas grid supplies. The generation of renewable energy is more efficient (85%) than conventional energy generation (52.5%), resulting in significant energy and cost savings.
2. Carbon savings
By using an organic source with a short carbon cycle* in a process which does not add any extra CO2 emissions, this results in an overall reduction in greenhouse gas emissions. The biogas produced is considered to be a sustainable, carbon-neutral energy source.
*The naturally occurring processes in which carbon is exchanged between living organisms and the environment.
The cycle is considered relatively short when it occurs in months/years compared to the millennia of long-term
The government has introduced significant financial incentives which encourage the use of renewable energy from waste:
Moreover, if the biogas capacity from AD is greater than the distillery’s energy load, the excess can be upgraded to biomethane gas (by cleaning to remove contaminant gases and increasing the methane content to the level of natural gas (>97%)). It can then be injected into the national gas grid or compressed for use as transport fuel. This provides an additional financial income.
The EU Waste Framework Directive provides the criteria on how businesses should collect, transport and dispose of their biowaste, to protect the environment. Using AD provides additional positive benefits and incomes for distilleries:
The production of high-quality digestate: expired process feedstock (90–95% original volume) which can be used as a superior biofertiliser or soil conditioner.
If this anaerobic digestate complies with the required quality standards, the site’s biowaste may no longer be regarded as normal waste and no longer subject to the normal waste management controls.
Wastewater treatment of digester effluents will provide reusable clean water, reducing consumption and waste discharges into sewers.
An increasing number of distilleries are using their organic waste materials to generate renewable energy.
The two main benefits are the huge energy and carbon savings.
Incentives are available to provide users of anaerobic digestion with additional financial income.
Anaerobic digestion will improve a site’s waste management practices.
Many distilleries are reducing rising effluent costs by using Anaerobic Digestion.