Anaerobic digestion in Scotland can make a key contribution to meeting the goals set out in the Scottish Energy Strategy, according to the UK’s trade body for anaerobic digestion (AD).
Charlotte Morton, Chief Executive of the Anaerobic Digestion and; Bioresources Association (ADBA), said today:
“The Scottish Government has set itself ambitious but necessary targets for generating renewable energy in its new Energy Strategy, and renewable heat and electricity produced through AD can make an important contribution to these goals, as well as reducing emissions from landfill, creating rural jobs, and helping to restore degraded soils.
Watch our video below for more information and then scroll down further for more details of Scottish Energy Strategy, including energy from waste targets:
“There are now over 50 operational AD plants spread across Scotland, recycling a range of wastes including animal slurries and manures, food waste, grass silage, sugar beet, and various grains and wheats from Scotland’s famous distilleries. With more than half of these plants commissioned within the last four years, farmers, businesses and government are increasingly seeing first-hand the multiple benefits that green gas delivers.”
AD is a technology that uses natural processes to recycle organic wastes and process purpose-grown energy crops into green gas that can then be used to produce renewable heat and power, low-carbon transport fuel, and nutrient-rich biofertiliser.
The Scottish Government’s Energy Strategy, the first of its kind in Scotland, sets a new target for at least 50% of all Scotland's heat, transport, and electricity consumption to be supplied from renewable sources by 2030. The Strategy notes that biogas and biomethane produced through AD will have a role to play in helping to decarbonise Scotland’s energy system, and notes that existing AD biomethane sites in Scotland already produce enough gas to supply the equivalent of 85,000 homes.
Morton’s comments come ahead of the ADBA Scottish National Conference 2018, taking place in Glasgow on the 28th February.
Last year’s conference was the first dedicated solely to the Scottish AD industry, and this year’s event will focus on AD’s potential contribution to business and farming in Scotland, with Cabinet Secretary for Environment, Climate Change, and Land Reform Roseanna Cunningham MSP giving the keynote presentation on Scotland’s proposed new Climate Change Bill.
Scotland has significant medium term targets for renewable energy since 2010 when they aimed to achieve: 11% of all heat by 2020, and 50% of all electricity.
Developing Scotland's Previous Anaerobic Digestion in Scotland Energy Strategy
Back in 2010 this Scottish study reported that energy from municipal waste could make a contribution to these targets, though it should be noted that not all energy produced by energy from waste plants would necessarily be classified as renewable.
The “Sustainable Development Commission Scotland – Energy from Waste Potential in Scotland (2010)” study shows that EfW in Scotland could contribute approximately 2.0 TWh of useful heat and 0.90 TWh of electricity per year, from incineration and anaerobic digestion combined.
This is equivalent to approximately 3% of Scotland‟s total heat demand and total electricity demand. The study takes existing and planned waste targets (Scotland's “Zero Waste Plan‟, currently under consultation) as a baseline.
Thus a 25% cap on combustion of Municipal Solid Waste (MSW) is taken as a given.
Waste diversion scenarios from the Scottish Government Waste Team are used to estimate proportions of all waste streams that might potentially be used to recover useful energy. Direct combustion of solid wastes (aka “incineration‟) and anaerobic digestion (AD) with biogas capture are the main energy from waste (EfW) technologies which were considered. via Sustainable Development Commission Scotland – Energy from Waste Potential in Scotland (2010) via Energy from Waste Potential in Scotland
Anaerobic Digestion Boom in Scotland as Food Waste Falls
ADBA noted in 2015 that while amount of food thrown away in Scotland each year has fallen by 8% since 2009, less than half of Scotland’s household waste was sent to landfill in 2014 – the first time that figure has ever dipped below the 50% mark, and a sign that technology like AD can help reduce demand on landfill space.
Further, under the Waste (Scotland) Regulations 2012 more will become available to due increased numbers of household food waste collections.
“These new ADBA figures show that AD is being taken extremely seriously by Scottish businesses,” commented Stephanie Clark, policy manager at Scottish Renewables.
“Increasingly, waste has value. The AD process recognises that, and turns things we don’t want, like food waste and farmyard slurry, into something we desperately need – clean, affordable electricity,” she continued.
Charlotte Morton, chief executive of ADBA, added:
“Scotland is leading the way in demonstrating how anaerobic digestion extracts value from our waste, while supporting farming resilience, reducing billions in carbon abatement costs, improving food security and production and generating employment and investment opportunities for rural economies.
“We are particularly excited to see AD plants working in partnership with local authorities to collect residents’ food waste and to distribute in its place heat and electricity for local homes. via Anaerobic Digestion Boom in Scotland as Food Waste Falls …
And, in the Wastewater Treatment Industry in Scotland they aim for self sufficiency:
Veolia helps Scottish Water achieve energy self-sufficiency
Veolia, the global resource management company, is now helping Scottish Water to achieve the target of energy self-sufficiency at its Seafield Wastewater Treatment Works, WwTW, the largest treatment works in the east of Scotland.
Since 2015 Veolia has extended the site’s capability to generate its own energy from 55 percent to around 85 percent in 2017 by boosting the renewable energy derived from a combination of anaerobic digestion in Scotland of sludge and biogas-fired combined-heat-and-power (CHP) plants.
In fact full self-sufficiency has already been achieved at various points during 2017 when Seafield used no electricity from the Grid.
Seafield WwTW treats waste for a population equivalent of approximately 850,000 people from Edinburgh and the surrounding area which equates to 300 million liters of wastewater every day—enough to fill 121 Olympic sized swimming pools. By implementing a range of innovations and increasing efficiency the target of energy self-sufficiency has been set as the practical target and will further sustainability and lower carbon emissions.
The advances to date mean that the Seafield site has also reduced its energy costs by 50 percent, which will help meet the value-for-money consumer criteria set for the industry.
The water industry is the fourth most energy intensive U.K. industry and uses around 3 percent of U.K. generated electricity for pumping, water treatment and waste management which directly contributes around 1 percent of the U.K.’s greenhouse gas (GHG) emissions.
Working in partnership with Scottish Water, Veolia have introduced a wide range of measures to derive renewable energy using anaerobic digestion in Scotland from sludge as a valuable resource. Measures installed to date include a thermal hydrolysis process that has increased biogas production by around 10 percent, investment in an additional CHP unit to provide greater energy generation and to take advantage of the additional biogas, and a further 3 percent increase in the yield of biogas. via Veolia helps Scottish Water achieve energy self-sufficiency
Conclusion on Anaerobic Digestion in Scotland
The Scottish Government has a much more progressive and optimistic outlook on the benefits of “green gas” (biogas) for anaerobic digestion in Scotland than the government sees for the process in England.
Is it too much to hope that the much larger benefits which could flow from similar policies being established and then promoted, via green gas incentives in England, will eventually become a reality?