What is anaerobic digestion (AD)?

AD works by naturally breaking down organic materials inside sealed tanks to generate biogas – a renewable fuel that comprises mainly of methane (the same as the gas in our gas supplies). Biogas can be converted into electricity or put through an ‘upgrader’ to produce biomethane – an alternative to fossil fuel gas – which can be readily injected into the gas grid network.

To find out more about AD, please watch this video:

The government has committed to achieving net zero carbon emissions by 2050 and aims to reduce methane emissions by 30% by 2030. Addressing the urgent need to establish sustainable systems and infrastructure for reducing greenhouse gas emissions is paramount. A recent announcement by DEFRA has underscored the necessity for all Local Authorities to implement segregated food waste collections by 2026. Therefore, it is crucial to develop local, sustainable methods for processing food waste, emphasizing the importance of environmentally responsible practices.

How will the new plant reduce the need for fossil fuels?

The plant will have the capacity to produce up to 1,000 cubic metres of biomethane an hour – enough to heat more than 7,400 homes. This means the AD Plant will have the ability to sustainably meet the town’s gas needs.

This will be produced using up to 100,000 tonnes of locally sourced organic and unavoidable food waste each year that could be collected from households or businesses and processed at the AD plant. The resulting ‘green gas’ (biomethane) is injected into the gas grid, displacing the need for fossil fuel.

Why are you building a plant to process food waste when surely we should be reducing the waste in the first place?

We do not seek to increase avoidable food waste, just to feed the plant. Food waste comes from many sources, including households, supermarkets and food manufacturers. A lot of this is unavoidable waste, such as peelings, offcuts and inedible parts of fruits and vegetables.

Currently, only 30% of the UK’s food waste is segregated (which means 70% goes to landfill or incineration). Suffolk is one of the councils that does not currently segregate its food waste. Therefore, the proposed AD plant presents an opportunity to process this waste in a much more sustainable way. The recent DEFRA announcement has clarified the requirement for all Local Authorities to segregate food waste collections by 2026, so having a sustainable means of processing this locally is vital.

Is there still a need for gas with the rise of electric, solar and wind?

While electric, solar and wind technologies are important elements in the energy transition, no single solution can address the complex energy demands of the UK. Following a mixed technology approach is essential to fully decarbonise the economy.

As they are weather-dependent. solar panels and wind turbines are intermittent sources of power. Nights and calm days can lead to dips in supply, and recent data shows that without gas, the UK would not have had enough electricity for 262 days of the year.  A large portion of the UK's electricity actually comes from turbines that are powered by gas.  Replacing the use of fossil fuel-derived gas with biomethane to power these turbines creates green electricity whilst also stopping the release of further Carbon Dioxide previously locked away underground into the atmosphere, preventing additional warming of the atmosphere.

AD complements these sources by providing a round-the-clock solution to generate green gas, turning an otherwise unused resource into valuable renewable energy. This ensures a consistent energy supply is available when needed.

In addition, the UK has a diverse mix of housing stock, certain property types, appliances or applications are unsuitable for electric technologies, therefore there is still a need for renewable gas in the long-term.

What is ‘green gas’ and will consumers notice a difference in the gas in their homes?

The ‘green’ definition is used to differentiate the gas from fossil fuel gas.  The biomethane produced from an AD plant is identical to the gas that is currently supplied to homes and businesses. It must meet strict quality criteria set by National Gas before it can be injected into the grid.

Therefore, consumers will see no difference in the gas they use.

How can using ‘green gas’ be any better for the environment than fossil fuel gas?

Food waste derived gas is sustainable, whereas fossil fuel derived gas is not sustainable (it will eventually run out), The carbon in fossil fuels has been buried for millions of years, and by burning it, we add to the amount of carbon already in the atmosphere.

Carbon dioxide released into the atmosphere from green gas is replacing carbon dioxide that was absorbed when the food was grown, so there is a continuous and sustainable cycle in place that does not keep adding more and more carbon to the atmosphere over time.

What other environmental benefits are there?

As a further result of the AD process, up to 90,000 tonnes of bio-fertiliser will also be produced annually. This is suitable for agricultural use and offers farmers a more sustainable alternative to synthetic fertilisers, which are extremely energy and carbon intensive to produce.

Up to 8,000 tonnes of CO2 is also produced in the process, which will be captured and supplied to industry for beneficial use, or sequestrated, permanently removing the CO2 from the atmosphere.

This AD Plant would be carbon negative. It will outperform Net Zero objectives.

What about air and noise pollution?

We have worked closely with noise and environmental consultants to address potential concerns in these areas.

A state-of-the-art odour abatement system will be installed to the food and organic waste processing hall. The system will create a negative air pressure inside the hall by sucking air into the building via louvres and expelling the odour laden air from the hall via a filtration process that removes odorous emissions. All waste tipping occurs within this closed building, coupled with the latest in automatic fast-shutting roller doors, meaning odour release will be minimised.

Additionally, we have replaced the large, covered lagoons that were storing the digestate (the bio-fertiliser produced at the end of the AD process), with covered and sealed storage tanks. This further reduces odour emissions, enabling residual gas to be fed back into the sealed gas cleaning process, without releasing it to the atmosphere.

A report has been commissioned to explore potential impact on the local community from the noise generated by the proposed development. Any recommendation to reduce noise levels in line with existing, will be acted upon. The noise impact assessment, including the recommendations, have been shared with the planning authority.

What about increased traffic on local highways?

We have commissioned a report to quantify the traffic and transport implications that the proposed development will have on the local community. This assessment evaluates the suitability of the highways to accommodate traffic associated with the proposed development.

The report recognises the close proximity of the development to Suffolk’s HGV route network, such as the A146. The report concludes that the local highway network can safely accommodate traffic generated by the proposed development, without any safety or operational capacity concerns. As part of the planning process, the outcome of this report has been shared with the planning authority.

Whilst not highlighted in the Transport Risk Assessment as an issue, a consequence of the site redesign is that the vehicle weighbridge will be located further away from the entrance, creating an increased vehicle holding area on-site that can hold several large vehicles at any given time – far more than would ever be expected to be on site. Therefore, the risk of queuing on the public highway is reduced from very low to almost negligible.

How will you reduce vehicle emissions to and from the site?

Electric vehicle (EV) charging points will be included on the site for use by staff and visitors.

Subject to technical feasibility and adoption of compatible vehicles by the local authority, a single truck EV charging point will also be installed on-site, enabling the recharging of EVs used within the waste collection and delivery process.

As the use of biomethane fuelled trucks becomes more widespread, we will encourage our industry partners to switch from diesel to biomethane.

Will local wildlife be affected?

As part of the project, we will improve local biodiversity through a Biodiversity Enhancement Scheme on site. The proposed enhancements will include bird and bee boxes, native hedgerows and trees as well as native species-rich grassland. The planting of trees and hedgerows will alleviate any visual impact which may be caused by the proposed development.

There is an airfield nearby, what about aviation safety?

We are aware of concerns regarding aviation safety and have liaised directly with the neighbouring aerodrome to address these concerns. We have appointed an independent aviation specialist to conduct an Aviation Safeguarding Assessment, which will be presented to the Civil Aviation Authority and Planning Authority. We are confident that residents and users of the airfield alike will be reassured that the site does not pose a risk.

To maximise aviation safety of the site, we have taken the following steps:

  • Altered the layout, moving all tanks and tall structures (including lightning protection masts) as far as possible to the north-western corner of the site. This further increases the separation between proposed structures, the flight path and obstacle limitation surfaces (OLS).
  • We have specifically ensured that no part of the infrastructure on site penetrates the OLS (obstacle limitation surface)
  • Whilst not a specific requirement, we have given consideration to, and provisioned for an emergency landing space to mitigate for engine failure by maintaining a flat corridor, which is parallel to the public road, and which is clear of any buildings or structures.

We invite you to view the video at the bottom of this page, which shows one of the test flights over an almost identical AD site with the flare running at full capacity to demonstrate there are no issues. The pilot who flew the plane that day stated:

“I have been informed that gas flaring is a backup measure used only in emergency. The flare was operated as a demonstration during my assessment flight. The flaring process was not visible from my aircraft and it did not disrupt its flightpath. In my opinion the process therefore does not present a risk to aircraft in flight”.

Will the AD plant be safe in a storm?

Given recent media coverage of a fire at an anaerobic digestion facility in Oxfordshire caused by a lightning strike, we understand there may be concerns regarding this issue.

Lightning strikes on AD plants are rare. Although it is not a mandatory part of site design and infrastructure, installing lightning protection is considered best practise.

We have designed a lightning protection system that complies with the relevant British Standard, and which provides protection for the entire site.

Where can we go to find more information and share our questions about the project?

Please visit the rest of our website to learn more about the Copland Way development.