Using Waste To Green The Gas Grid

Charlotte Morton, chief executive of the Anaerobic Digestion & Bioresources Association (ADBA), sets out how recycling organic wastes can play a key role in greening the UK’s gas grid… 

When questioned on the government’s climate-change credentials, ministers are often quick to point out that renewables now account for 30% of electricity generation; indeed, 75% of all emissions reduction since 2012 has come from the power sector.

While these figures are commendable, the same unfortunately cannot be said for heat generation. While emissions from power have fallen dramatically in recent years, emissions from heat (and other sectors) have plateaued.

Biomethane is already abating more than 250,000 tonnes of carbon each year (equivalent to taking almost 100,000 cars off the road each year) by recycling wastes, displacing fossil-fuel energy, and reducing the need for fossil-fuel-based artificial fertilisers through producing nutrient-rich biofertiliser as part of the AD process.

The Committee on Climate Change’s 2018 Report to Parliament says that “Detailed plans should be published to phase out the installation of high carbon fossil fuel heating in homes and businesses in the 2020s”. Heat is arguably one of the most difficult sectors to decarbonise in the UK’s energy system, and doing so presents a huge challenge for policymakers and politicians.

But right in front of their eyes is a technology that can make a significant contribution to decarbonising the UK’s gas grid today, as well as providing a whole suite of other benefits. That technology is anaerobic digestion (AD), and one of its key products is biomethane.

Biomethane is produced by the natural breakdown of organic wastes and/or energy crops in an AD tank, which produces methane-rich biogas that can be upgraded into biomethane. This green gas can be used either as a direct replacement for natural gas in the gas grid or as a transport fuel for large vehicles such as HGVs and buses.

The benefits of biomethane

First, using biomethane to help decarbonise the gas grid is good for energy security. Green gas is home-grown and supplies are constant and reliable, meaning that the UK doesn’t need to be as dependent on imported fossil-fuel gas.

As a source of baseload energy, biogas offers greater value than other intermittent options such as solar or wind as its storage costs or alternative generation required for periods of low output are lower. Our conservative calculations suggest that this value is between £30 and £60/MWh in the UK.

Biomethane is already abating more than 250,000 tonnes of carbon each year (equivalent to taking almost 100,000 cars off the road each year) by recycling wastes, displacing fossil-fuel energy, and reducing the need for fossil-fuel-based artificial fertilisers through producing nutrient-rich biofertiliser as part of the AD process.

Importantly, biomethane can also replace natural gas in our heating supplies with no need for consumers to change technology or behaviour, in contrast to other low-carbon heating options that would require the eye-wateringly expensive replacement of every boiler in the country.

The AD process that produces biomethane also helps to achieve a range of government objectives, including:

  • Reducing emissions from, and providing a waste-treatment solution for, organic wastes such as food waste, manures, and sewage, abating significant amounts of carbon and methane;
  • Supporting farmers by diversifying their income and by recycling nutrients back to farmland to support food production;
  • Strengthening the rural economy by employing 3,500 people, with the potential for a further 30,000 if the industry meets its full potential; and
  • Developing low-carbon technology and expertise that can be exported to the global biogas market, which has the potential to be worth a staggering £1 trillion.

Biomethane’s potential

With almost 100 biomethane AD plants currently in operation across the UK and almost 50 more expected to be built over the next two years as a result of recent changes to incentives, millions of people can already use renewable heat generated through AD.

The 13 TWh of biogas produced by the AD industry today, however, is only a quarter of the 53 TWh that AD as a technology could produce if all suitable organic wastes (including manures, slurries, sewage, and inedible food waste) are recycled through AD. And with additional investment in research and development, the total energy output potential of AD in the UK could be as large as 78 TWh, enough to provide for 30% of UK domestic gas demand by 2032.

ADBA is calling on ministers to urgently confirm support for biomethane into the 2020s and beyond, whether through an extension of the RHI or a similar policy mechanism that will give investors long-term certainty.

Of course, it’s not just ADBA that is trumpeting the benefits and potential of biomethane. The Committee on Climate Change, the government’s watchdog that sets and track progress on the UK’s Carbon Budgets, regards biomethane as a “low-regret option” for reducing emissions, while Parliament’s Energy & Climate Change Committee has identified biomethane as “critical” to meeting the UK’s 2020 target for generating 12% of heat from renewable sources.

National Grid’s Future Energy Scenarios (FES) identify low-carbon gas as having a central role in decarbonising the gas grid, with AD and biomethane figuring most strongly in the ‘Two Degrees’ scenario under which the targets of the Paris Accord and the UK’s Carbon Budgets would be met.

Professional service company KPMG has also estimated that using green gas and existing infrastructure is 2-3 times cheaper than other scenarios for delivering heat, while think-tank Policy Exchange has encouraged expansion in biomethane for grid injection, noting that it “goes with the grain of consumer preferences and minimises costs to the consumer”.

Support for biomethane moving forward

To date, the UK biomethane industry has been able to grow thanks to the Renewable Heat Incentive (RHI), the government’s support mechanism for renewable heat generation. Support from government has been essential to the development of a successful biomethane industry and will continue to be so over the coming years (in the absence of an effective carbon price) while the cost of building and running plants and the comparative cost of renewables continue to fall.

However, despite a recent boost to the scheme, the RHI effectively closes to new biomethane projects injecting into the grid at the end of 2020. The Tariff Guarantees introduced as a result of recent changes are not on offer to plants commissioning beyond 31 December 2020. Without support for biomethane post-2020, government currently has no practical plans for gas grid decarbonisation in the 2020s and beyond.

This is why ADBA is calling on ministers to urgently confirm support for biomethane into the 2020s and beyond, whether through an extension of the RHI or a similar policy mechanism that will give investors long-term certainty.

It’s important as well, of course, that biomethane supported by the RHI (or its replacement) continues to deliver value for money for government and the taxpayer. ADBA is working closely with the AD industry to reduce the need for incentives by improving performance, reducing costs, investing in R&D, introducing the AD Certification Scheme, and continuing to work with government and regulators.

Indeed, it is only by working closely with the AD industry and government that we can ensure that biomethane continues to deliver such an exceptional return on investment, helping the UK become a greener and more circular economy.

You can find out more about ADBA’s work at adbioresources.orgor at @adbioresources.


 

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