“Sustainable development… meeting the needs of the present without compromising the ability of future generations to meet their own needs.” – 1987 Brundtland Report
When it comes to looking after the future of our planet we all know there are changes both big and small we must continue to make as a society in how we live our day-to-day lives. But… how exactly does Anaerobic Digestion (AD) fit in to the picture to ensure a more sustainable future?
Renewable Energy and The Circular Economy
The task of reducing the world’s dependency on fossil fuels is one of greatest challenges of our generation. Not only do the greenhouse gas emissions created by these fuels damage our environment they are also of course a finite source of energy.
The biogas created through AD is used to power CHP (Combined Heat & Power) units and produce renewable electricity and heat. It estimated that AD could generate 10-20 TWh of electricity per year by 2020. To put this in context, the UK’s largest power station Drax sold 27.1 TWh of electricity in 2012.
Making the shift towards Circular Economy will be the key to sustainability in many areas. The AD process has this concept at its core, for example diverting food waste from landfill and utilising it instead to create a valuable resource which can then be used within the food system itself e.g. renewable energy for transporting food waste, food manufacturing and food retailing.
Biomethane and Biogas
Reducing the transport sector’s reliance on imported diesel is crucial to improve its sustainability. Plus, in order to tackle the effects of diesel on climate change the government is challenging the sector to reduce their greenhouse gas emissions by 6% by 2020.
As well as power for electric vehicles, the AD process has the capacity to create another green fuel – Biomethane.
Created by upgrading excess biogas, Biomethane represents a renewable and carbon-neutral form of CNG and is suitable for injection in to the gas grid.
Biofuel targets that came into force in April 2018 aim to double the use of renewable fuels in the transport sector within 15 years, plus, changes to the Renewable Transport Fuel Obligation (RTFO) means that owners of transport fuel who supply 450,000 litres a year or more, must ensure the mix at least 12.4% biofuel by 2032. Both Biomethane and Biogas created through AD will have a vital role to play in achieving these targets.
Many synthetic fertilisers used in farming and horticulture are made from fossil fuels. The nitrogen- rich digestate created organically through AD provides a sustainable alternative these products reducing the need for chemical fertilisers. In addition, as digestate has a faster absorption rate than chemical fertilisers, the risk of contamination to rivers, stream and other waterways is greatly reduced.
Reports have also indicated the role that AD could play in improving the sustainability of our food systems. A wide range of changes will be necessary to ensure we are able to feed a population of 10 billion people by 2050. These changes include making improvements to our food production systems and it is thought that the use of AD and digestate in adjusting nutrient ratios to more efficiently match crop needs could be valuable in this area.