Bioenergy in the UK’s path to net zero


As the UK moves closer to its 2050 net zero target, it is becoming increasingly critical that we accelerate investment into stable, renewable energy solutions. While the Energy and Climate Intelligence Unit (ECIU) has recently reported that for the first time ever investments in fossil fuel projects have begun to be overtaken by renewable energy sources, there is still a lot of work to be done if the UK is to be on track to achieve carbon neutrality in less than 30-years’ time.

The recent energy price crisis, caused by the war in Ukraine, has shown how vulnerable the UK’s energy supply is to disruptions such as geopolitical instability as well as extreme weather events and supply chain issues. As part of the response to this, we saw last month UK Energy Security Secretary Grant Shapps invite his US counterpart, Jennifer Granholm, to discuss energy independence as the UK looks to ramp up its homegrown renewable energy sources.

We need to look at all options

However, despite the government claiming in 2021 that it wanted all electricity to be generated from low-carbon sources by 2035, the government spending watchdog, National Audit Office (NAO), has warned that the government has made little progress in producing a long-term delivery plan.  While we have made progress in areas like wind generation, the UK needs to look at other sources of renewable power if we are to meet growing demand for energy.

Anaerobic Digestion (AD) is a solution that offers just that – local, secure, and reliable renewable energy. According to the Anaerobic Digestion and Bioresources Association (ADBA), AD could provide up to 30 per cent of the UK’s domestic gas demand by 2030, reducing our reliance on imported gas and ensuring a sustainable energy supply.

AD is the process of breaking down organic matter, such as food waste or agricultural products, in a controlled environment. Removing the technical terminology, it is akin to the process that takes place in the human body every day – digesting food to create energy.  The process produces a high performing, low carbon biogas – a mixture of methane and carbon dioxide. This can be used for renewable electricity generation or injected into the gas grid as biomethane (a renewable natural gas), for home heating and vehicle fuel use, directly replacing fossil fuels.

 “Anaerobic digestion will increasingly become an important part of the UK’s energy mix as we move away from our reliance on fossil fuels,” Peter Sharpe, CEO of Bio Capital, who own and operate a large portfolio of AD plants across the UK, says. “Investing in these local energy solutions will be key when bridging the transition away from gas and LNG imports”.

Supporting the war on food waste

As reported by the European Biogas Association (EBA), biomethane is the cheapest and most scalable form of renewable gas available today. As a direct substitute for natural gas, it can be readily stored and deployed across the whole existing energy system.

The organic matter that is fed into the digestion tanks can come from a range of sources: One of which is food waste. The UK throws away around 9.5 million tonnes of food waste in a single year. While this figure undoubtably needs to be reduced from the outset, what is worse is that much of this goes directly to landfill. In landfills this food waste then breaks down to release harmful greenhouses gases – most notably methane, a gas that is 25 times more harmful than carbon dioxide. Energy Saving Trust highlight that approximately eight to ten per cent of the world’s greenhouse gas emission relate to food waste. If it were a country, this would make it the third biggest emitter, sitting only behind the US and China.

Prior to Covid-19, the Department for Environment, Food and Rural Affairs (Defra) had begun to explore mandatory food waste reporting for some large retailers. However, this has since been delayed. Defra has also since gone quiet on their plan for food waste collections to be available for all homes in England by the end of 2023, which was a part of the Resource and Waste Strategy.

“While these are far from progressing, the increasing recognition of the environmental impact of food waste is likely to push more and more private and public bodies to look for green solutions to extend the life cycle of their waste,” Sharpe continues. “It is about recognising these problems, and finding a smart and deliverable solution that works – for both our planet and people.”

Giving back to the land

Beyond renewable energy, anaerobic digestion offers numerous positive environmental and social impacts. A by-product of the process is a bio-fertiliser, which can act as a direct substitute for highly expansive and carbon intensive chemical fertilisers. This is particularly salient in today’s economic landscape with food prices being pushed up by the price of chemical fertilisers. Figures from the Agriculture and Horticulture Development Board (AHDB) have shown that in May 2022, the price of UK-produced ammonia nitrate fertiliser in Great Britain had increased by 152 per cent since the previous year and imported prices had increased by 171 per cent. The price of potassium chloride fertiliser (potash) had increased by 165 per cent and phosphate fertilisers had increased by between 120 per cent and 128 per cent depending on the type.

As a result, the voices of farmers calling for support are increasingly growing louder. In February’s National Farmers Union Annual Conference, the group urged the government to support domestic food production, which included pushing for sustainable farming practices, new technologies, and schemes to incentivise positive environmental action by farmers. 

“With the right technology and process, the valuable natural bio-fertiliser produced by the AD process has been shown to build soil carbon, enhance soil health, increase resilience to pests and weeds and provide significantly higher yields than carbon intensive chemical fertilisers,” Sharpe concludes. “In our current climate, enabling farmers with this will support the sustainable production of UK grown food.

“From collecting food waste with vehicles fuelled by biomethane to using the by-products of the anaerobic digestion process to support crop growth, an optimised process of AD offers a true model of circularity. These ideas are vital to meet the UK’s net zero goals whilst supporting local economies and livelihoods”. 

In a macro environment of unstable gas prices, global shortage of chemical fertilisers and a need to lower emissions across the board, anaerobic digestion provides a sustainable answer to these challenges. Through positive investment and Government support to local authorities and farmers, it can serve a key part of supporting the UK through the bumpy energy transition road the country is set to face ahead.

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