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In the wake of recent developments regarding China’s decision to no longer accept waste from foreign countries, it is time we started thinking differently about how to manage our waste, especially considering that China has been the largest importer of UK-exported waste.

Methane gas is a by-product of landfills, pits of land where disposed waste is buried in, which contributes to climate change. Around 25% of man-made global warming can be attributed to methane. The largest cause of man-made methane in the UK is landfills. However, what is currently a negative externality of our waste could in fact be utilised as an energy source.  

When methane is released into the atmosphere, it acts as a greenhouse gas by absorbing heat from the sun. It is one of the most harmful greenhouse gases in terms of its contribution to climate change; 28 times more potent than carbon dioxide at absorbing infrared radiation from the sun and in turn warming the planet.

But methane has a half-life of seven years, considerably less than carbon dioxide, which takes between 50 to 300 years to be removed from the atmosphere. This means that reducing the level of methane which is released into the atmosphere would have a comparatively quicker effect on reversing climate change than reductions in carbon dioxide emissions.

If biodegradable waste decomposes in an environment where there is no oxygen, such as a landfill, it produces methane. In recent times, the UK has been ranked eighth in the world for the most methane emissions released from landfills. On this basis and given methane’s prominent role in contributing to climate change, we need to urgently seek solutions for reducing methane from landfills.

One option is to incinerate waste to generate electricity and hot water. This option does not release any methane as the waste is incinerated rather than left to decompose. An excellent example of this in practice is the Amager Bakke waste-to-energy plant in Copenhagen. Over 400,000 tonnes of waste is incinerated in the plant every year, providing electricity and hot water for over half a million people. The bottom ash that is left over from the incineration process is also recycled by being used in roading construction, saving gravel.

Waste-to-energy plants such as this don’t have to be a blot on the landscape nor have a significant impact on air quality. Amager Bakke is aesthetically designed, and as for air quality, you can even partake in skiing and rock climbing on its roof right below the chimney stacks. This is thanks to its flue gas cleaning technology, which reduced sulphur (So2) emissions by 99.5% and nitrogen oxide (NOx) levels to one tenth of what they were in the 40-year-old incineration plant that Amager Bakke replaced. The plant’s emitted exhaust is comprised of water vapour as opposed to smoke.

Another solution to curbing methane emissions from landfill is to use methane recovery systems. Waste is placed within a sealed landfill chamber, and as it decomposes the methane gas amasses at the top of the chamber. The methane is then extracted out of the chamber through pipes. It can be combusted for energy generation, or simply burned in order to convert it to carbon dioxide (methane reacts to combustion by converting to carbon dioxide and water) and mitigate its impact on climate change.  

An alternative to combusting the extracted methane is to use it as a source of natural gas. Bright Blue’s recent Pressure in the Pipelines report touted greater use of biomethane (a mixture of methane, carbon dioxide, and other gases) in the gas network as a way of reducing emissions, as well as requiring gas suppliers to deliver increasing portions of low carbon gas, including biomethane. Once extracted, the landfill’s methane is converted to biomethane in a biosynthetic natural gas (BioSNG) plant, where it then goes on to supply the National Grid. This kind of technology has already arrived on UK shores, with the country’s first BioSNG plant having opened in Swindon in 2016.

These examples demonstrate that there are pragmatic options when it comes to managing our waste. In the case of landfills; a negative externality (methane) can be transformed into a positive input (source of energy). The UK needs to start thinking differently about waste management, and perhaps even seeing the potential opportunities in it.

Patrick Hall is a Researcher at Bright Blue.