Britain’s circular economy strategy is part of a wider plan to mitigate climate change and will change how society operates; the materials we use, how we generate electricity, and how we consume and manage our waste.
The circular economy
The circular economy model is a key framework to realise a more sustainable future. It focuses on keeping materials and resources within the system for as long as possible or, if possible, indefinitely. As opposed to a linear model, where a resource is extracted, refined, consumed, and disposed, the circular model ensures the material is repurposed and reused either through recycling into another product, extraction of key metals and other materials, or potentially even conversion into energy. This approach is one of many potential catalysts for a sustainable future, where fewer virgin resources are extracted from rapidly depleting sources.
The role of waste
To fully embrace and refine this model, a major part of the circular economy is managing waste. The UK is currently following the EU strategy, with the aims to achieve a 60% recycling target for municipal waste by 2030. Landfill capacity is expected to expire by 2023 and, while newer sites will become available, they are not being opened fast enough to meet demand. The UK does not yet have its own strategy on dealing with waste management as part of the circular economy and, with the looming shadow of Brexit, it is unclear if these targets will be maintained or others developed.
Currently, UK policy is having a positive impact on waste. While 48% of total waste in 2016 was recycled and around 25% went to landfill – which includes municipal waste from construction and industry – the weightage amount is still too high to be sustainable. Municipal solid waste is defined as waste coming from homes, schools, shops and small businesses. Since 2010, there has been a 40% reduction in municipal waste sent to the landfill.
Energy from waste
One of the ways that we can reduce waste sent to landfill and support a more sustainable economy is by extracting energy from the waste for heating and electricity generation, a process known as energy from waste (EfW). The process outputs heat, which can be used for district heating, while the energy can be used to create steam, which is in turn used to generate electricity. Materials such as glass and metals, which do not combust in the process, are left at the bottom, known as bottom ash and can be used as aggregates in construction, with the remaining metals being sent for recycling.
There are many advantages of this approach. For instance, when we compare carbon emissions of EfW against sending waste to landfill, EfW has much lower emissions. Research on EfW has also shown that the health risks – cancerous and non-cancerous – from waste incineration are five times lower in comparison to landfill. Given that we are running out of landfill space, EfW can take as much as 60Mt out of landfill in the coming decade and be used to provide electricity to 1.8m homes. Currently, around 3.5m tonnes of waste are being sent abroad to be utilised to generate electricity, which the UK is then buying back.
There are still problems with EfW, the EU has recently removed EfW from its directives to be incorporated into the circular economy on the grounds that, compared to traditional fossil fuels, EfW produces twice as much carbon per unit of electricity generated, passing the limit set by the EU. Research into the technology involved in ensuring the emissions are purified is improving, however, and treatment of air pollution control (APC) residues may rectify some of these problems in the coming years.
What does this mean for the UK?
Weighing up the pros and cons, EfW should be a key part of the UK’s post-Brexit policies. Given we are unable to meet space demand for landfills, EfW will enable us to free up space and reduce the amount of CO2 emissions that would normally be generated. Exporting waste – to be turned into electricity and to be bought back – makes no sense when there is an option to reduce costs, provide investment opportunities, and create domestic capacity for baseline power generation.
EfW does not necessarily need to be a long term strategy for the UK. With society undergoing a transformation in the energy sector and climate being at the top of the agenda, using EfW in a short-to-medium term could provide a stepping stone to a cleaner world. While there are concerns about EfW emissions, a comprehensive national strategy needs to be developed to effectively place EfW in the future of the UK’s circular economy.
Usman Farooq is a data scientist at an international engineering consultancy.