Refuse put to use: the case for biomethane in the UK
For many Britons, turning the heating on (or up) is a reflexive action for a large part of the year. So much so that approximately 47 percent of energy in the UK is used for heating – which is in turn responsible for one-third of the country’s carbon emissions. Suffice it to say that decarbonising heat is on the agenda for anyone seeking to reduce the UK’s carbon footprint, and one particular solution is increasingly sparking corporate interest: biomethane gas.
What is biomethane and how is it produced?
According to Dr. Kiara Zennaro, the Head of Biogas at the Renewable Energy Association, the UK has the fastest-growing biomethane sector in the world. Biogas is produced through anaerobic digestion – a natural process in which plant and animal-derived material is broken down by microorganisms in an airtight container. It’s not wholly dissimilar to what occurs in your average garden compost heap, but an anaerobic digester must be a sealed vessel in which bacteria can work without the presence of oxygen.
“The microorganisms are pretty much the same,” Zennaro says of the difference between composting and anaerobic digestion. “They are already in the waste; you don’t have to add anything. In the absence of oxygen, they will break down material, though it will need some stirring and mechanical mixing to make it more effective.”
The type of organic matter ‘fed’ to a digester tends to fall into two categories: municipal food waste and other waste and residues (e.g. from agriculture or processing), and so-called ‘energy crops’ grown solely to be used in the process of making biogas.
There are two major by-products of anaerobic digestion, the so-called ‘digestate’ matter and biogas. The former can be used as a crop fertiliser because of its nutrient-rich composition, while the latter, a methane-rich gas, can be burned at the site of the anaerobic digestion plant to generate both renewable power and heat.
However, biogas still contains a relatively large amount of CO2 and other impurities. It must be further processed in order to be injected into the National Grid, where it can then be used for heat, electricity or transport in much the same way as traditional natural gas. This purified form of biogas is referred to as biomethane.
Which businesses and organisations in the UK are currently using biomethane?
In March of this year, the state-of-the-art Leyland Filling Station, a collaboration between CNG Fuels and the National Grid, launched in Lancashire, with the facility set to open for business at the end of this year. It is the UK’s first high-pressure connected compressed natural gas (CNG) filling station and it exclusively supplies biomethane created from food waste. CNG can be used in place of traditional petrol, diesel or propane, and the station is capable of refuelling up to 500 HGVs in a single day.
“By being connected to the high pressure system, it means the carbon footprint is much lower when compared to other filling stations because it requires less energy demand,” Zennaro says.
With their large cumulative quantities of food waste, and long-distance transport needs, major supermarket chains have naturally started to notice the potential of biomethane. Waitrose is already powering two of the Scania tractors used at its regional distribution centre at Leyland using compressed biomethane from the nearby filling station.
Not to be outdone, Sainsbury’s has recently partnered with recycling and waste management company ReFood to power a handful of its stores with biomethane. Under the partnership, ReFood will collect food waste from two of the supermarket’s depots, convert it into gas and fertiliser at one of its anaerobic digestion facilities and inject the biomethane into the grid. A third party will then export the gas to select Sainsbury’s locations where it will be used to generate carbon-neutral heat and electricity.
“I think we’re seeing an increased interest from energy consumers, from corporate companies like Diageo and big supermarkets,” says Zennaro of biomethane’s growing appeal. “So far they have been mainly interested in green electricity, but now the green gas element is starting to raise more interest.”
What are the challenges currently facing the sector?
Zennaro sees biomethane as one of a growing number of renewable solutions that will need to be utilised in order to further decarbonise the UK’s energy sector. However, there are a number of legislative obstacles to its growth.
“The main issue is that the policy landscape keeps changing,” she says. “It’s very difficult for investors and developers to know what level of support we’ll have by the time they build a plant and the plant becomes operational.”
Biomethane plants are reliant upon the UK government’s Renewable Heat Incentive -- a policy introduced in 2011 in which the government pays a tariff on each kilowatt hour of biomethane injected into the grid. In recent years, the tariff has been cut through a budget control mechanism designed to apply reductions if a particular technology is developing too quickly.
In addition, suitable feedstock for an anaerobic digester can be surprisingly difficult to come by. The government intends to restrict the growth of energy crops and their use in biogas plants because of concerns that they will displace land that could be used for growing food crops. It follows that the industry could turn to food waste for feedstocks, but even that is easier said than done:
“Forty-five percent of local authorities in England are not collecting food waste, because food waste collections are quite costly and are not mandated by Government,” Zennaro says.
So, could biomethane ever become a market rival for traditional gas?
Policy restrictions aside, it is unlikely that biomethane will ever usurp natural gas singlehandedly. But this isn’t to say that it won’t account for an integral portion of the UK’s energy mix. Biomethane will not be a rival but a partner to natural gas.
“We could probably meet 20 percent of the UK gas demand 2035,” Zennaro says. “There is a huge opportunity for biomethane to fuel heavy vehicles, buses, and decarbonise the transport sector, as well. We really lag behind in terms of achieving our target for renewable transport, and the Government really sees biomethane as strategic not just to decarbonise the transport sector, but to improve air quality, which is the other important issue.”
“There is huge potential, that’s the bottom line.”
Carbon dioxide removal revenues worth £2bn a year by 2030
Carbon dioxide removal revenues could reach £2bn a year by 2030 in the UK with costs per megatonne totalling up to £400 million, according to the National Infrastructure Commission.
Engineered greenhouse gas removals will become "a major new infrastructure sector" in the coming decades - although costs are uncertain given removal technologies are in their infancy - and revenues could match that of the UK’s water sector by 2050. The Commission’s analysis suggests engineered removals technologies need to have capacity to remove five to ten megatonnes of carbon dioxide no later than 2030, and between 40 and 100 megatonnes by 2050.
The Commission states technologies fit into two categories: extracting carbon dioxide directly out of the air; and bioenergy with carbon capture technology – processing biomass to recapture carbon dioxide absorbed as the fuel grew. In both cases, the captured CO2 is then stored permanently out of the atmosphere, typically under the seabed.
The report sets out how the engineered removal and storage of carbon dioxide offers the most realistic way to mitigate the final slice of emissions expected to remain by the 2040s from sources that don’t currently have a decarbonisation solution, like aviation and agriculture.
It stresses that the potential of these technologies is “not an excuse to delay necessary action elsewhere” and cannot replace efforts to reduce emissions from sectors like road transport or power, where removals would be a more expensive alternative.
The critical role these technologies will play in meeting climate targets means government must rapidly kick start the sector so that it becomes viable by the 2030s, according to the report, which was commissioned by government in November 2020.
Early movement by the UK to develop the expertise and capacity in greenhouse gas removal technologies could create a comparative advantage, with the prospect of other countries needing to procure the knowledge and skills the UK develops.
The Commission recommends that government should support the development of this new sector in the short term with policies that drive delivery of these technologies and create demand through obligations on polluting industries, which will over time enable a competitive market to develop. Robust independent regulation must also be put in place from the start to help build public and investor confidence.
While the burden of these costs could be shared by different parts of industries required to pay for removals or in part shared with government, the report acknowledges that, over the longer term, the aim should be to have polluting sectors pay for removals they need to reach carbon targets.
Polluting industries are likely to pass a proportion of the costs onto consumers. While those with bigger household expenditures will pay more than those on lower incomes, the report underlines that government will need to identify ways of protecting vulnerable consumers and to decide where in relevant industry supply chains the costs should fall.
Chair of the National Infrastructure Commission, Sir John Armitt, said taking steps to clean our air is something we’re going to have to get used to, just as we already manage our wastewater and household refuse.
"While engineered removals will not be everyone’s favourite device in the toolkit, they are there for the hardest jobs. And in the overall project of mitigating our impact on the planet for the sake of generations to come, we need every tool we can find," he said.
“But to get close to having the sector operating where and when we need it to, the government needs to get ahead of the game now. The adaptive approach to market building we recommend will create the best environment for emerging technologies to develop quickly and show their worth, avoiding the need for government to pick winners. We know from the dramatic fall in the cost of renewables that this approach works and we must apply the lessons learned to this novel, but necessary, technology.”
The Intergovernmental Panel on Climate Change and International Energy Agency estimate a global capacity for engineered removals of 2,000 to 16,000 megatonnes of carbon dioxide each year by 2050 will be needed in order to meet global reduction targets.
Yesterday Summit Carbon Solutions received "a strategic investment" from John Deere to advance a major CCUS project (click here). The project will accelerate decarbonisation efforts across the agriculture industry by enabling the production of low carbon ethanol, resulting in the production of more sustainable food, feed, and fuel. Summit Carbon Solutions has partnered with 31 biorefineries across the Midwest United States to capture and permanently sequester their CO2 emissions.
Cory Reed, President, Agriculture & Turf Division of John Deere, said: "Carbon neutral ethanol would have a positive impact on the environment and bolster the long-term sustainability of the agriculture industry. The work Summit Carbon Solutions is doing will be critical in delivering on these goals."
McKinsey highlights a number of CCUS methods which can drive CO2 to net zero:
- Today’s leader: Enhanced oil recovery Among CO2 uses by industry, enhanced oil recovery leads the field. It accounts for around 90 percent of all CO2 usage today
- Cementing in CO2 for the ages New processes could lock up CO2 permanently in concrete, “storing” CO2 in buildings, sidewalks, or anywhere else concrete is used
- Carbon neutral fuel for jets Technically, CO2 could be used to create virtually any type of fuel. Through a chemical reaction, CO2 captured from industry can be combined with hydrogen to create synthetic gasoline, jet fuel, and diesel
- Capturing CO2 from ambient air - anywhere Direct air capture (DAC) could push CO2 emissions into negative territory in a big way
- The biomass-energy cycle: CO2 neutral or even negative Bioenergy with carbon capture and storage relies on nature to remove CO2 from the atmosphere for use elsewhere