Environmental Impact Assessment (EIA) for Anaerobic Digestion Projects: What Is It and How Much Does It Cost?
Environmental Impact Assessment (EIA) is a critical part of planning any significant project in the anaerobic digestion and biogas industry. If you’re planning to build or expand a biogas plant in the UK, understanding EIAs and their costs is essential.
In this guide, we’ll explain what an EIA involves, when it’s required for AD projects and how much you should budget for this process. We’ll also share tips to get the most value from an EIA and ensure your project moves forward smoothly.
What is an Environmental Impact Assessment (EIA)?
An Environmental Impact Assessment (EIA) is a structured process that evaluates how a proposed project might affect the environment. In practical terms, it means collecting detailed information about potential environmental effects on land, air, water, ecology, local communities, etc. and presenting it to the planning authority before the project can be approved. The goal is to ensure that decision-makers (and the public) know about any significant environmental impacts in advance and that developers have a plan to avoid or reduce those impacts.
In the UK, EIAs are governed by law, notably the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, which implement the requirements of the EU’s EIA Directive into UK planning rules. If your project is likely to have a notable effect on the environment, you must go through an EIA as part of your planning permission process. The output of an EIA is an Environmental Statement (ES), a report containing all the findings, which the local council will review before deciding on your application.
EIA is not required for every project, only those that meet certain criteria. When it is required, it’s a mandatory part of getting approval. Think of it as an extensive environmental “health check” for your project. During an EIA, specialists will study various aspects such as: potential impacts on wildlife habitats, emissions to air and water, noise and traffic from the site, visual impact on the landscape, effect on local residents, and so on. Public input is also typically involved – the community and other stakeholders can comment on the proposals and the environmental studies. The end result is that everyone understands the environmental trade-offs of the project and how you’ll address them, before a shovel hits the ground.
From a developer’s perspective, an EIA might sound a bit daunting, however, it’s also an opportunity. A well-done EIA will highlight ways to improve your project. For example, suggesting better odour control at your AD plant, or safer traffic management for trucks – which can make the project more sustainable and often more acceptable to the public and regulators. Rather than just a bureaucratic hurdle, think of EIA as a vital planning tool that ensures your biogas facility is designed responsibly and in harmony with its environment.
When is an EIA Required for Anaerobic Digestion Projects?
One of the first questions to ask is whether your particular anaerobic digestion project will actually require an Environmental Impact Assessment. In the UK, not all AD or biogas projects need a full EIA, it depends on the project’s size, nature, and location. EIA requirements are generally determined by schedules in the EIA Regulations, which list types of projects and thresholds. AD plants can fall under categories like waste management facilities or energy projects, which are often in “Schedule 2” (projects that need EIA if they are likely to have significant effects).
As a rule of thumb, your AD/biogas development will likely need an EIA if it’s large in scale or situated in an environmentally sensitive area. A common benchmark referenced in the industry is an AD facility processing over 50,000 tonnes of waste per year. Above that volume, an EIA is usually mandatory. For context, 50,000 tonnes/year is roughly equivalent to about 135–150 tonnes of feedstock per day – so this threshold captures fairly large commercial biogas plants (for example, those taking in municipal food waste or large agricultural/industrial AD units). Additionally, any size of AD project might require EIA if the site is in a sensitive location – such as a protected wildlife area, Green Belt land, a floodplain, or close to lots of homes where odour/noise could be an issue. Environmental sensitivity can trigger an EIA even if the project is not huge.
It’s important to note that these are not hard-and-fast rules, but guidance. In fact, many local planning authorities take a precautionary approach: some councils have asked for EIAs even for projects well under the 50,000 tonne threshold if they felt there could be significant impacts. For example, a mid-sized farm AD plant might be asked to do an EIA if it’s near a village and people worry about odour or traffic. On the other hand, a similar sized plant in a remote area might avoid a full EIA if impacts are clearly minimal.
So, how do you know for sure if you need an EIA?
The process usually starts with a Screening. Screening is an application or request to the planning authority where you describe your project, and the authority decides whether an EIA is required or not. You can submit a screening request early in your planning stage, this is highly recommended. The council will evaluate your proposal against the regulations and issue a screening opinion confirming if an EIA is needed. If they say “yes, EIA required,” then you must go through the EIA process and submit an Environmental Statement with your planning application. If they say “no EIA needed,” you can proceed without that step (though you’ll still need to address environmental issues in the normal planning documents, just not at the same level of detail).
Top Tip
It’s wise to engage in a pre-application consultation with your local planning authority and even the community early on. Discuss your AD project informally and raise the question of EIA before you submit anything formal. Early dialogue can give you a sense of whether the council is likely to demand an EIA and what their main concerns might be, allowing you to prepare accordingly. As industry guidance suggests, initiating a pre-application enquiry and informing the local community at an early stage can save time and money by heading off issues upfront.
The EIA Process: Steps Involved (Step-by-Step Overview)
The EIA process might seem complex, but it can be broken down into a series of standard steps. Each step serves a purpose in making sure your project’s impacts are thoroughly examined and addressed.
Here’s an overview of the typical EIA stages for a biogas project:
Screening
Determining if an EIA is needed for the project. You (or the council) compare the project to threshold criteria and likely impacts. The local authority then issues a screening opinion stating whether a full EIA is required. If your proposed AD plant could have significant effects (e.g. due to size or location), they will say “EIA needed” and you proceed to the next steps.
Scoping
Defining the scope of the EIA study. In this stage, you identify which environmental topics and issues need to be investigated in detail. You can ask the council for a scoping opinion on what to include. For example, relevant issues for an AD plant might include odour emissions, traffic, noise, impacts on local waterways, ecology (if near natural habitats), landscape/visual impact, etc. The scoping step ensures the EIA focuses on key significant issues and sets terms of reference for consultants.
Baseline Studies
Gathering data on the current environment. Your team of environmental consultants will conduct surveys and research to establish the baseline conditions before development. This can involve field studies such as wildlife and habitat surveys (to see what species are on site), measuring background noise levels, air and water quality sampling, traffic counts, archaeological assessments, and more. These baseline data provide a benchmark to predict how your project might change things. It can take several months to collect adequate baseline info, especially if seasonal studies (e.g. breeding bird surveys in spring) are needed.
Impact Assessment
Predicting and evaluating impacts. Using the baseline data and project details, specialists assess what effects the AD plant could have on each aspect of the environment. For instance, modeling the dispersion of air emissions (odour, bioaerosols), calculating the increase in traffic on local roads, assessing risk of water pollution from digestate, evaluating greenhouse gas savings, etc. Both construction impacts (temporary) and operational impacts (long-term) are considered. Each potential impact is examined for its significance – how severe it would be, and on whom or what. If an impact is significant, it must be addressed.
Mitigation Measures
Identifying solutions to avoid or reduce impacts. A core part of EIA is figuring out how to mitigate negative effects. For every significant impact identified, the EIA will propose mitigation measures or design changes. For example, if traffic is an issue, the mitigation might be a new access road or limiting truck hours. If noise is a concern, perhaps acoustical enclosures for equipment. Odour concerns might be mitigated by advanced scrubbing systems and management plans. Sometimes compensation measures are included (e.g. planting trees elsewhere to offset habitat loss). At the end of this step, you should have a clear plan of how you will deal with each environmental impact. Importantly, if an impact is too harmful and can’t be mitigated, you may need to reconsider or redesign that aspect of the project.
Environmental Statements
Reporting the findings. All the work above gets compiled into an Environmental Statement. The ES document will typically include: a Non-Technical Summary, chapters detailing each environmental topic (with baseline, impact analysis, mitigation, and any residual impacts after mitigation), appendices with technical data, and drawings/maps. The ES is the document that you submit to the authorities and the public. It must be prepared by competent experts and cover all the required information as per the EIA regulations. This is the centre piece of your EIA, the deliverable that decision-makers will study.
Public Consultation
Stakeholder and public engagement. Once you have submitted the Environmental Statement along with your planning application, it gets publicized. Statutory bodies (like the Environment Agency, Natural England, local highways authority, etc.) are consulted for their feedback. The general public also has the right to view the ES (often online or at council offices) and submit comments. For a biogas project, you might hold public exhibitions or meetings as well to explain the project and EIA findings. Public consultation ensures transparency and community input.
Decision & Conditions
Planning decision-making. Finally, the local planning authority examines the Environmental Statement together with all the feedback from consultees and the public. They then decide whether to grant planning permission for your AD plant, and under what conditions. The EIA plays a big role here as the council must take the ES and all comments into account in their decision. If approval is given, typically there will be a set of conditions attached, some of which likely enforce the mitigation measures you committed to in the EIA (e.g. a condition to implement noise insulation, or to do environmental monitoring during operation). If the project is refused, the EIA results might be part of the reasoning (e.g. “project refused due to unacceptable impact on landscape that cannot be mitigated”). In either case, the decision is made public along with main reasons.
Monitoring & Follow-up
Ensuring compliance and monitoring impacts. Although strictly this goes beyond the EIA report, it’s worth noting: if your project is approved, you may be required to carry out environmental monitoring or follow-up actions during construction and operation. This could include things like noise monitoring at the site boundary, regular checks of water quality in a nearby stream, or an ecological clerk of works supervising during construction to protect wildlife. These measures ensure that the project actually does what it promised in the EIA. Many developers integrate these into an Environmental Management Plan. Monitoring results might need to be reported to the council. This stage closes the loop – checking that the predictions made in the EIA are accurate and that mitigation is effective.
An EIA is multi-faceted and collaborative. You’ll likely have a team of experts involved, environmental consultants specialised in areas like ecology, noise, air quality, traffic, archaeology, landscape, etc. It’s essentially a project within the project. The timeline for a full EIA can range widely, but for a typical AD plant you should expect it to take on the order of 6 to 12 months from start to finish (including the consultation period). Larger or more controversial projects can stretch longer
How Much Does an EIA Cost?
What is the cost of an Environmental Impact Assessment? The answer is, unsurprisingly, “it depends.” EIA costs can vary dramatically based on the size and complexity of your project, and the scope of studies required. We’ll break down the factors in a moment, but first let’s talk ballpark figures.
For many typical projects (not mega infrastructure, but say a commercial development or mid-sized industrial facility), an EIA often costs somewhere in the range of £10,000 to £100,000
On the lower end (~£10k–£20k) might be an EIA for a relatively small or straightforward project – perhaps a modest AD plant with few impact areas to study, or cases where a lot of environmental data already exists.
Mid-range (£20k–£50k) could cover many medium-scale AD projects where you need several different surveys (ecology, noise, air, traffic, etc.) but nothing out of the ordinary.
Higher end (£50k–£100k+) would be for complex or larger projects, where extensive fieldwork is required and maybe the EIA report is very detailed. If an AD plant is large (handling hundreds of thousands of tonnes per year) or contentious, you might see costs climb in this upper range due to the need for more in-depth analysis and possibly legal reviews.
Key Factors Influencing EIA Cost
Why do some EIAs cost £15,000 while others reach £150,000? Several factors influence the overall cost:
Project Size and Complexity
Larger projects – or those with multiple components – require more extensive studies. There is more land to survey, more potential impact pathways, and more data to analyse. A small on-farm AD unit might only need a few focused studies, whereas a large, waste-fed biogas plant could involve comprehensive traffic impact assessments, detailed air dispersion modelling, and extensive ecological surveys. Novel technologies or complex sites can also add to the effort. In short: the bigger and more complicated the project, the more expensive the EIA.
Environmental Sensitivity of the Site
If your project is located in or near a sensitive environment, the EIA will need to explore these issues in greater depth. For example, building next to a protected habitat or wetland may require year-long ecological studies, habitat assessments, and detailed hydrogeological analysis. Similarly, proximity to communities can lead to additional social impact and health assessments. In contrast, a less sensitive brownfield site might avoid many of these costly surveys.
Scope of Studies Required
Depending on the likely impacts, you may need to commission a range of specialist studies. Common areas for a biogas plant include noise, air quality (including odour), climate impact, traffic and transport, biodiversity, water quality and hydrology, landscape and visual impact, archaeology and heritage, and human health risk. Each study requires experts, and the broader the scope, the higher the cost.
Consultant and Expert Fees
Professional fees from environmental consultants form a large part of EIA costs. These vary by firm and expertise. Top-tier firms often charge more, but experienced consultants can work more efficiently and navigate the process with fewer delays. Typically, you will need an EIA coordinator or project manager to compile the Environmental Statement, alongside technical specialists. Additional expenses such as laboratory testing of soil or water samples, and travel for survey teams, should also be factored in.
Baseline Data Collection Needs
The level of effort needed to establish baseline environmental conditions has a big effect on cost. If existing data is limited, consultants may need to undertake detailed new surveys. Some studies can be quick, but others – such as seasonal ecology surveys, continuous air quality monitoring, or lengthy traffic counts – can be time-consuming. Hiring specialists, for example bat surveyors, adds to the bill.
Public Consultation and Hearings
Organising community meetings, producing non-technical summaries, and responding to feedback also adds to the budget. If a project faces significant public interest or opposition, more investment may be required in communications, visual materials, or facilitation. In some cases, legal costs may arise if objections lead to formal hearings or inquiries.
Regulatory Fees and Administration
In the UK, the EIA process itself does not carry large government fees. You will pay the normal planning application fee and, if required, additional charges for permits such as environmental permits from the Environment Agency. One minor administrative cost to expect is the requirement to advertise the EIA in a local newspaper, which typically costs a few hundred pounds.
To manage costs effectively, it is sensible to plan your EIA strategy early. Keep the focus proportionate to your project and avoid unnecessary studies, but do not cut corners where significant issues exist. A good consultant will help tailor the assessment to your site’s real risks and requirements.
Turning EIA from Burden to Benefit: Best Practices
Although an Environmental Impact Assessment can initially seem like a barrier, a proactive approach can transform it into a valuable tool for project success. Here are some best practices:
Start Early and Integrate EIA into Planning: Consider environmental factors from the feasibility stage. Early screening can influence site selection and design, and ensures that seasonal surveys are carried out on time.
Engage Qualified Experts: Work with consultants experienced in UK regulations and AD projects. They can identify what is essential and propose effective mitigation strategies.
Focus on Key Impacts: Keep the assessment targeted on the most significant environmental issues. This helps control both costs and the volume of documentation.
Maintain Communication with Stakeholders: Build an open dialogue with planning authorities, regulators, and the community. Early engagement often reduces opposition and smooths the approval process.
Use Findings to Improve the Project: Take EIA recommendations seriously. Adjustments in design or operation can make the project more sustainable and easier to approve.
Plan for Mitigation and Monitoring: Budget for mitigation measures and ensure clear plans are in place for environmental monitoring during construction and operation.
Stay Up to Date with Regulations: Keep informed of evolving guidance, such as potential changes towards Environmental Outcomes Reports, and apply the latest standards in your EIA.
By embedding the EIA into project development rather than treating it as a tick-box exercise, you are more likely to achieve consent smoothly and build a project that operates with fewer issues in the long term.
Navigating EIA for a Successful Biogas Project
Environmental Impact Assessment may seem complex, but with the right approach it becomes a powerful tool to ensure your anaerobic digestion project is both compliant and sustainable.
In summary, always check early on if an EIA is needed and plan accordingly. If it is required, allocate the necessary time and budget and assemble a capable team to carry it out. Use the EIA process to your advantage: address environmental issues proactively, engage stakeholders, and refine your project design. Doing so will not only satisfy the regulators but also improve your project’s performance and community relations.
At the end of the day, an EIA is about responsible development, making sure that as we build more biogas plants and renewable energy infrastructure, we do so in a way that safeguards the environment and community well-being. For operators, investors, and managers in the AD industry, being well-versed in EIA requirements is now part of the job.
Need help with the EIA or planning process for your biogas project?
Don’t hesitate to reach out for professional support. Contact the BIOCON Group today. We can provide guidance on feasibility, regulatory compliance, and managing the EIA and planning applications.
Getting expert advice can de-risk your project and ensure that environmental assessments and permissions are handled efficiently.
