Energy security: what is the role of the waste industry?

Nature Energy

Circular’s editor Ian Farrell asks has the UK’s dependence on imported energy weakened our energy security? And if so, what can the waste industry do to help redress the balance?

At the heart of the UK’s cost-of-living crisis is energy. Russia’s invasion of Ukraine, and the sanctions that swiftly followed it, have left a hole in the world’s natural gas supplies that has pushed up wholesale prices to record levels and left some countries desperately scrabbling around for supplies.

The UK is not one of them. Unlike Germany, Denmark and other European countries, there is no direct gas pipeline from Russia to the UK, so any Russian imports come in the form of liquified natural gas (LNG) shipments. These made up just 4% of imports in 2021 and, as of June 2022, have now dropped to zero. The government is confident that “the UK is in no way dependent on Russian gas supply”.

This does not, however, mean that we are immune to the current energy crisis. The market for gas is global, so a rise in wholesale prices affects all countries, not just those that import gas from Russia. There are other factors at play too: a cold winter in Europe last year left gas stocks unusually low and demand is increasing as the worldwide economy rebounds after the Covid-19 pandemic.

There are roughly 650-700 anaerobic digesters operating in the UK right now, including those on farms.

The UK also imports electricity from Norway, which has more than it needs thanks to abundant hydroelectric power, but poor rainfall in Scandinavia means a surplus might not be available in future months.

Traditionally, energy insecurity is mitigated by not relying too heavily on one source of power. This is an area where – in theory at least – the UK has been making some progress. Wind, solar, tidal and nuclear all work together, alongside gas, in a strategy that’s designed to insulate us from market volatility. The problem is that around half of the UK’s electricity is still made from natural gas, and the vast majority of residential homes still rely on gas heating.

The government is committed to increasing energy diversity, but this will take time as new renewable and nuclear facilities are built. What’s needed in the short and middle term is a source of gas that fills the hole. And it’s here that the waste industry might be able to help.

Biogas is a mixture of methane and CO2 that’s formed by decomposing organic waste. It’s made in anaerobic digesters and captured from landfill sites. Once the two gases have been separated, the biomethane component (which is identical to natural gas) can be either “dropped into” existing gas supply networks or used to generate electricity that is fed to the national grid. Which is a lot better than allowing it to vent into the atmosphere, where it has a greenhouse effect 30 times more powerful than CO2. 

Too good to be true?


In a world where we have too much waste and not enough energy, it’s hard to fathom why we don’t use technology such as anaerobic digestion more – to plug both gaps in one go. Look at the figures and the potential for biogas is obvious.

Jenny Grant, head of organics and natural capital at the Renewable Energy Association (REA) says: “There are roughly 650-700 anaerobic digesters operating in the UK right now, including those on farms.

“About 200 of these are fed with waste, with 120 taking in food waste. In 2020, these processed 3.5 million tonnes of waste, but WRAP [Waste and Resources Action Programme] has estimated that 9.5 million tonnes of food is thrown away every year. There is just massive potential for anaerobic digestion at the moment.”

So, what’s the hold up? Grant says the waste industry is waiting for government to reveal the fine details of its consistent collections legislation before pulling the trigger on investment. “When food-waste collections are mandated, there will be much more organic matter for anaerobic digesters and therefore more renewable energy. 

In the future, your can of CocaCola or cold pint of lager could well be carbonised with gas produced from waste.

“Our members tell us they are ready to expand facilities or build new ones, but until they have the concrete details of the policy – which we are still waiting for from Defra – nobody is going to be able to build anything,” she says.

While investment might be on hold, Grant admits there is some spare capacity in the system right now for food waste. “It’s a buyers’ market,” she says. “The spare capacity means that gate fees are low right now and this is an opportunity to move food waste further up the hierarchy and away from landfill or incineration.”

Anaerobic digestion also alleviates other problems brought on by the natural gas shortage. Both food-grade CO2 and mineral fertiliser rely on natural gas in their production, making them very expensive right now (to the point where much CO2 production has ceased). Fortunately, they are both also produced in the anaerobic digestion processes – the digestate is a superb fertiliser that’s 80% readily available nitrogen; CO2 can be separated from the biogas itself.

Currently, about 15% of the UK’s CO2 comes from anaerobic digestion, but this has the potential to increase if more plants retrofit with CO2 capture technology – filling the void left by the spiralling cost of fossil-fuel-derived natural gas. 

“In the future, your can of CocaCola or cold pint of lager could well be carbonised with gas produced from waste,” Grant chuckles.

Pieces in the puzzle

Nature Energy

Anaerobic digestion is not the only form of power production the waste industry can offer. You’ll find energy-from-waste (EfW) plants all over the country, which burn residual waste to produce energy.

It’s a technology that makes a bigger overall contribution to UK power than anaerobic digestion at the moment, though this is likely to change as we get more food waste collected at the kerbside. Nevertheless, EfW has a crucial part to play in energy production because it’s a base-load technology.

“A straight replacement of fossil gas with digester biomethane isn’t the whole picture,” says Stuart Hayward-Higham, technical development director at Suez. “Wind, solar, hydropower and anaerobic digestion can all fluctuate, but EfW doesn’t, so it can be used as a reliable base-load energy source – just as we do with fossil gas.”

Hayward-Higham explains that as the contribution from EfW replaces natural gas, so that gas is then available for heating homes. “It’s a good contributor and helps energy security, for sure,” he says.

In an ideal world, we wouldn’t have EfW or landfill.

EfW is a controversial topic among the public. Its critics point out that it’s not a sustainable energy source, since it’s often burning things such as non-recyclable plastic, which has its origins in fossil fuels. It also emits greenhouse gases and other air pollutants. But Hayward-Higham argues the pros and cons of EfW need to be weighed against each other. “In an ideal world, we wouldn’t have EfW or landfill,” he argues. “But until the country stops producing waste that cannot be recycled, EfW is a good contributor.

“Nobody claims it’s a completely renewable energy source – it’s a mixture,” he says. “The government doesn’t incentivise it as renewable. But when I’m off-setting EfW against the fossil gas that would have been used by a gas-fired power station, I don’t just count the renewable part of the EfW, I count the fossil fuel part too. I’m offsetting fossil with fossil,” he says.

The bigger picture

Nature Energy

Technologies such as anaerobic digestion and EfW have a large role to play in future UK energy security, but it’s also worth looking a little higher up the waste hierarchy for inspiration. We often talk about dealing with waste, but what about preventing it in the first place?

It’s the same with energy. As well as considering how to find more sustainable power sources, we must reduce how much we use too. There are ways of doing this in homes and businesses, of course: insulating buildings, redesigning heating systems, turning off appliances at night and not using standby modes. But there are also ways the waste sector can help behind the scenes. 

We are literally offsetting other people’s need for energy by recycling; by saving energy elsewhere in the economy.

The very act of recycling materials saves vast amounts of energy compared to sourcing virgin materials, for example with glass, aluminium and steel. “We are literally offsetting other people’s need for energy by recycling; by saving energy elsewhere in the economy,” Hayward-Higham says. “The energy saved reduces our dependence on imported energy and makes us more energy-secure as a nation.”

The waste sector already does a lot to help energy security and much of it is hidden – behind-the-scenes activities that are perhaps taken for granted by the population as a whole. But there is an opportunity to do much more in the coming years. And it is an opportunity: to protect energy consumers from price spikes, build new revenue streams in our sector and ultimately build a better cleaner world to live in.

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