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Capturing emissions from slurry

Date Published: 31/10/2023

According to the Climate Change Committee’s ‘Progress in reducing emissions’ 2023 report, 48% of the UK’s methane emissions come from agriculture. Speaking in the Future of Farming seminar at Cenex LCV on 7th September 2023, Penny Atkins, CEO of the International Fugitive Emissions Abatement Association (IFEAA), shared an update on progress towards methane emissions reduction in agriculture and other industries in the UK.   

Read on to understand the key points from her talk and to find out how capture of methane from slurry presents an opportunity to reduce fugitive methane emissions, provide a source of renewable energy and improve dairy farm incomes.

What is meant by fugitive emissions?

Fugitive emissions are any emissions from unintentional or intentional release of greenhouse gases (GHG) to the atmosphere, as a result of human activities. Sources of fugitive emissions come from across all industry sectors, and include:

  • Leaking, venting and flaring from oil and gas processing
  • Emissions from processing wastewater
  • Emissions from agricultural waste like ammonia and methane

Methane from slurry is an example of fugitive emissions from the agricultural sector.

Why focus on methane in agriculture?

In the UK, there has been a reduction in methane emissions in recent years, but more progress is needed. Looking at data from 1990 to 2020, emissions have declined primarily as a result of reduction in coal use and reduced quantities of waste going to landfill. Now, the largest sources of methane in the UK are agriculture and waste management.

The UK has signed up to the global methane pledge, committing the country to reducing methane emissions by 30% compared to 2020 levels by 2030. The net zero strategy has several measures to contribute towards achieving this target, which include:

  • In oil and gas there is ambition to replace 15,500 km of cast iron gas pipes with plastic pipes in 5 years, to cease routine flaring and venting by 2030
  • In agriculture there’s an ambition for 75% of farmers in England to be engaged in low carbon practices by 2030, rising to 85% by 2035. It also includes implementation of the Farming Innovation Programme and Farming Investment Fund to improve environmental performance and profitability, and investigation of feed additives to reduce methane from ruminants
  • For waste, no more than 10% municipal waste to landfill by 2035

But are these measures enough? The Climate Change Committee has been looking at the data and measures in place to report on the UK’s progress towards net zero targets. The evidence they present is not encouraging. They’ve concluded that the measures will have a role in advancing progress, but our contribution towards the methane pledge is weak and the UK is currently unlikely to meet the target of 30% reduction by 2030.  

What has been achieved in terms of methane emissions reduction is far less than what is needed. In agriculture, there has been a 0.4% reduction in the last six years, leaving an extra 3.1% reduction which remains to be achieved.

Reducing methane emissions from livestock farming

Bennamann and CNH have developed technology for the capture and use of methane from slurry, which could reduce the methane emissions from livestock farming. By covering slurry to capture the methane, purifying it and then selling it as energy, methane emissions can be prevented and the gas used as a replacement for fossil fuel derived natural gas.

In Cornwall, the county council funded a pilot project, to understand the potential benefits of the technology in the region. Trenance Farm, one of the farms involved in the pilot, was able to reduce the carbon footprint from 800 tonnes of CO2 equivalent to 87 tonnes of CO2 equivalent in the first year after installing the cover to capture the methane from slurry.

The county council was interested in the emissions savings, the potential for local production of renewable energy and also whether the capture and sale of methane could increase skilled employment opportunities for people living in the region.

The project identified that the main sources of methane in Cornwall were 300,000 cattle and wastewater from the 585,000 people living in the region. It was estimated that by covering and capturing methane from slurry throughout farms in Cornwall, 89,876 tonnes of methane could be abated each year. The volume of methane that can potentially be captured from slurry in Cornwall equates to approximately a third of the region’s natural gas usage, so capturing the methane provides an excellent opportunity to contribute towards the decarbonisation of energy in the region.

Earning income from methane capture

The local authority was also interested in the income that could potentially be derived from methane capture. In the study, they calculated that if the captured methane is used to replace natural gas for heating homes, then income from the sale of the methane will be approximately 10p per kg. But if it is used for road traffic fuel and RTFO credits are claimed, the region would be looking at approximately £66 million gross income from methane. Finally, if the methane were to be used to generate electricity for EV charging points in the region, the total income generated from methane in the region could be as much as £150 million.

From the perspective of an individual 100-cow dairy farm, the methane could be used on-farm in place of fossil fuel, which save approximately £10,000 per year. Or, the farm could earn between £25,000 to £50,000 per year by selling the gas. In other words, they concluded that capture and sale of methane from slurry could change the financial picture for dairy farms in the region.

In summary, the activities currently taking place in the UK to reduce methane emissions are not expected to enable the country to meet its commitment, so there is a need to do more. In her talk, Penny Atkins shared how capturing fugitive methane emissions from slurry could lead to reduced emissions and improved farm incomes. Find out more here.