About Anaerobic Digestion

Anaerobic digestion (AD) is the process that transforms organic waste into renewable gas.

Anaerobic digestion: The future of sustainable energy 

Anaerobic digestion (AD) is one of the most promising technologies in the renewable energy sector, and at ENGIE we’re proud to be a leader in its UK development and implementation. AD is a biological process that breaks down organic materials, such as agricultural waste, food waste, and sewage, to produce biogas. This biogas is cleaned and can then be injected into the national gas transmission system or converted into electricity and heat, creating a sustainable and efficient energy source. 

 

The circular economy

Anaerobic digestion plays a vital role in the circular economy by transforming waste into valuable resources. By diverting organic waste from landfills and converting it into biogas, we reduce waste, lower emissions, and generate clean energy. This process supports a more sustainable system where resources are continuously reused, reducing reliance on fossil fuels and promoting sustainability across industries. 

Circular economy

Supporting rural economies

  • Farmers are paid fair, guaranteed and consistent prices for the feedstock they supply to AD plants, allowing them to diversify. It also offers some protection from the fluctuations in commodity markets.
  • The high-quality renewable fertilisers that AD facilities supply across agriculture, breaks the link with fossil fuel derived artificial fertiliser. In turn, this drives down the agricultural carbon foot print.
  • Renewable energy can be supplied directly to rural businesses, providing a cost effective and fully traceable alternative to fossil fuels.
  • AD plants work in partnership with feedstock providers to ensure best practice land management for a better environment.
Circular economy

Supporting the food industry

  • AD plants can convert waste from food manufacturers into renewable energy, rather then disposing of it in a less environmentally friendly manner.
  • Innovative food production centres such as vertical and urban farms are ideally suited to AD plants, because they can take advantage of the energy and heat that is produced.
Circular economy

Boosting community success

  • The AD sector provides jobs both at the facilities and within local communities (including managing feedstock production, fertiliser management and maintenance services).
  • AD facilities provide educational opportunities for all age groups. Partnerships with local communities and education providers support local communities and get residents really bought into green energy. This provides a platform to inspire future innovation and the green leaders of tomorrow.
  • Innovative projects are generated, including the development of new and exciting uses for AD outputs. These range from artificial fertiliser replacement, to CO2-based animal feeds – and even alcohol.

Achieving net zero

At ENGIE, we are committed to achieving net zero emissions through the expansion of anaerobic digestion technology.

By scaling up biomethane and AD projects and improving their efficiency, we help reduce carbon emissions while generating green energy. AD not only contributes to the fight against climate change but also supports industries in their efforts to meet sustainability goals and reduce their carbon emissions. 

 

 

Debunking myths about anaerobic digestion

MYTH: Anaerobic digestion is just for big companies who want to improve their reputation

Anaerobic digestion is great for businesses of all sizes that produce organic waste. It may seem like it’s more popular with big companies, but that’s only because they tend to shout about their green practices more!

Over half of the feedstock providers we work with are small local businesses and farmers. Anaerobic digestion is not just a rich person’s play thing, it’s a real way to sustainably create value out of waste. For many farmers, AD is especially useful as our digestate bi-product makes great fertilizer and the biogas helps fuel their farms.

MYTH: Anaerobic digestion machines reduce job opportunities

Anaerobic digestion actually increases the demand for jobs. While machinery does the bulk of the digesting work, the whole operation requires a hardworking, meticulous team to check the machines are running as they should be. On top of this, AD boosts a range of other jobs, such as managing feedstock production, fertiliser, and maintenance.

MYTH: Anaerobic digestion takes crops that should be entering the food chain

Some people are concerned that using crops as a feedstock for producing green energy is a waste, when these crops could become food instead. Arable land is already being used for purposes other than food production, though – more cereals are grown for brewing and distilling than for energy crops!

It’s not possible or sustainable to continuously grow food crops, as the soil will gradually lose its nutrients. AD feedstock crops are grown as part of a crop rotation cycle with natural digestate fertiliser, helping to replenish organic matter and improve the soil. This means farmers can grow better quality food in the next cycle.

MYTH: Anaerobic digestion is smelly

Some of the feedstocks that fuel a digester can produce a bit of a stink (such as manure and chicken litter), but these smells aren’t permanent. Plants want to turn their feedstock into green gas as quickly and efficiently as possible, so the feedstock isn’t around for long. This also means that the smell rarely spreads beyond the plant. In fact, one of our AD plants is situated directly next to a wedding venue and we haven’t had any complaints!

MYTH: Anaerobic digestion creates increased traffic and disruption in local communities

This is the most common misconception about AD. AD plants are often situated on agricultural land, as this is the most beneficial location for our feedstock providers who tend to be farmers and small, rural businesses. This helps cut travel costs and allows farmers to make profit from their waste.

Prior to AD plants, farmers had to remove their waste, (often via large lorries or tractors), to a landfill or similar facility that could be miles away. Instead, AD diverts the waste to a different place, which is usually just a short trip down the road.

Prior to AD plants, farmers spread their agricultural wastes and residues, such as farmyard manure and cow slurry, straight onto their land. Therefore these feedstocks were already being transported, but they are now being directed to a local AD plant, rather than being spread on fields.

MYTH: Anaerobic digestion sites are dangerous and messy

We aren’t too sure where this myth came from, as all the AD sites we’ve seen are safe – and very clean!

Having clean, tidy and safe working conditions for our team means we are able to operate even more efficiently.