Anaerobic Digestion Costs: How Much Does a Digester Cost?

Anaerobic digestion costs depend on the plant’s capacity, feedstock, location and equipment. The price of a digester tank is only one part of the installed project cost. To estimate a project properly, calculate both the initial investment and the annual cost of operating it, then compare these with realistic income and savings.

Published examples can help establish the scale of investment, but they are not interchangeable quotations. A dairy-manure system, a packaged small-scale plant and a commercial food-waste facility can have very different requirements.

This guide explains what to include in an AD budget, how to compare published figures, and how to use Washington State University’s free calculator. For an introduction to the process, see our guide to anaerobic digestion.

The following video we produced set out the principal costs to be considered:

How much does an anaerobic digester cost?

There is no single price that applies to every anaerobic digester. Start by defining the project: how much material it will accept, how it will be treated, whether the gas will produce electricity and heat or be upgraded to biomethane, and where the digestate will go.

The examples below show reported development or facility values. They do not establish a typical farm-digester price or a universal cost range.

The dates above are announcement dates, not independently established construction-price base years. Do not convert historical figures into current quotations simply by applying an exchange rate. These projects differ in scale and scope, so their figures should not be averaged.

Farm-scale anaerobic digestion cost examples

Published farm projects show why herd size, feedstocks and the use of the gas must accompany any cost figure. These US dairy examples are historical reference points, not 2026 supplier quotations or a price range for a typical UK farm.

How to use these examples: the figures have not been adjusted for inflation or converted into pounds. Installation dates are not necessarily the cost base years. The projects differ in technology, gas use and included infrastructure, so dividing their costs by cow numbers would create a misleading comparison. Fair Oaks is an exceptionally large dairy installation. For your own farm, obtain a current quotation with a defined scope and model operating costs, feedstock availability, energy use and financing separately.

What is included in the capital cost?

Ask suppliers to state what their quotation includes and excludes. Use the same scope when comparing proposals.

• Site and civil works: access, foundations, drainage, buildings and utilities.
• Feedstock reception and preparation: storage, pumps and any sorting, depackaging or treatment required.
• Digestion equipment: tanks, heating, mixing, pipework, controls and instrumentation.
• Gas handling and use: gas storage, treatment, flare, CHP equipment or biomethane upgrading.
• Connections: electrical or gas-network connection and associated metering or compression.
• Digestate management: storage, separation and any further treatment.
• Project delivery: design, approvals, commissioning and training.
• Budget allowances: contingency, working capital, taxes and financing during construction, where applicable.

Keep land purchases and recoverable taxes visible as separate assumptions. An equipment-only price can look attractive while leaving substantial construction and connection costs outside the quotation.

What are the annual running costs?

Build an operating budget around the proposed plant and site. Include labour, servicing, repairs, replacement parts, insurance, utilities, consumables, monitoring and administration. Add feedstock purchasing or collection costs where applicable, and digestate storage, transport and outlet costs.

Allow for planned maintenance and interruptions. Model net saleable energy after the plant’s own consumption, rather than treating gross gas production as revenue. Separate annual operating expenditure from loan repayments and major replacement investments so the cash-flow model remains clear.

Is anaerobic digestion profitable?

Profitability depends on the relationship between investment, running costs and dependable revenue. Consider energy sales or avoided energy purchases, contracted waste-treatment income, and realistic digestate value. Count each benefit once and check whether the project qualifies for any assumed support.

A gate fee is a waste-treatment payment, not the construction cost of the plant. Its contribution depends on contracts and the cost of accepting and treating that material.

Simple payback can provide an initial comparison, but a discounted cash-flow assessment also accounts for timing. The EPA AgSTAR Project Development Handbook, particularly Chapter 6, provides a framework for examining project economics.

Test lower gas yield, downtime, lower selling prices, higher operating costs and construction overruns. A project that relies on every assumption being favourable needs further work before investment.

Free anaerobic digestion costs calculator from WSU

Washington State University publishes the Anaerobic Digester System Enterprise Budget Calculator and a user guide. It supports dairy AD investment scenarios, including different gas-use and nutrient-recovery options.

The calculator is useful for comparing assumptions. It is not a supplier quotation, and its default values should not be treated as current local prices.

1. Download the workbook and guide from WSU’s resource page.
2. Save a separate working copy for your project.
3. Choose the relevant technology options.
4. Replace editable assumptions with local quotations, feedstock data and realistic prices.
5. Create downside, base and upside scenarios.
6. Review the outputs and assumptions with your project adviser.

WSU says the workbook uses macros. Follow the university’s guidance and your organisation’s Excel security requirements. The resource page currently lists ADBCv2-48.xlsm and a PDF guide; the listing alone does not establish that its default costs have been updated for 2026.

How to compare cost per tonne or per unit of energy

Keep capacity and output measures consistent. Capital cost divided by annual treatment capacity describes investment per unit of capacity; it is not the annual treatment cost per tonne. For operating cost per tonne, divide annual operating expenditure by actual annual throughput.

Likewise, investment per installed electrical kilowatt is different from cost per kilowatt-hour generated. An energy-cost comparison should specify net output, operating life, maintenance, financing and the treatment of other revenues.

European pocket-digestion costs: historical case studies

Inagro’s 2015 brochure, Small-scale anaerobic digestion: case studies in Western Europe, documents five projects. Two dairy examples illustrate the importance of identifying infrastructure costs and CHP separately.

Source: Inagro pocket-digestion case studies (PDF), pages 6 and 11. These are historical figures, not current quotations. Paybacks depend on the report’s local energy prices and support arrangements; they should not be transferred to a present-day UK project.

CREST: a second tool for modelling AD economics

The CREST Cost of Renewable Energy Spreadsheet Tool provides Excel cash-flow models, including an anaerobic digestion model, for assessing project economics and the effects of support schemes. It can help examine first-year and levelised energy costs, complementing the dairy-focused WSU calculator above.

The official resource page also provides a 2013 user manual. CREST originated in a 2009–2010 US partnership; it is a modelling framework rather than a current plant price list. Replace costs, energy prices, tax and financing assumptions, and support rules with values appropriate to your location and project. Check the manual and model suitability before relying on the results.

AD project cost checklist

Use this checklist when requesting quotations and preparing your project budget. For each item, record the amount, price date, source, whether it is included in a supplier quotation, and any exclusions. Mark an item as not applicable with a reason rather than leaving it blank.

Capital and project delivery

• ☐ Land or lease costs; site surveys, ground conditions and site preparation.
• ☐ Access, foundations, buildings, drainage, utilities and civil works.
• ☐ Feedstock reception, storage, preparation, depackaging and any required pasteurisation.
• ☐ Digesters, heating, mixing, pumps, pipework, controls and instrumentation.
• ☐ Gas storage, gas treatment, flare and safety equipment.
• ☐ CHP and heat distribution, or biomethane upgrading, compression and metering.
• ☐ Electricity or gas connection, connection studies and network reinforcement.
• ☐ Digestate separation, treatment, storage and loading facilities.
• ☐ Design, planning, permits, professional fees and project management.
• ☐ Commissioning, performance testing, training and initial spare parts.
• ☐ Construction contingency, initial working capital and taxes. Identify recoverable taxes separately.

Annual operating costs

• ☐ Labour, management, training and administration.
• ☐ Feedstock purchases, collection, haulage and handling.
• ☐ Electricity, heat, water and other utilities used by the plant.
• ☐ Servicing, repairs, spare parts, lubricants, chemicals and other consumables.
• ☐ Monitoring, sampling, laboratory analysis and permit compliance.
• ☐ Insurance, rent, rates and other recurring charges.
• ☐ Digestate storage, transport, spreading, treatment and outlet charges.
• ☐ Waste disposal, rejected loads and cleaning.
• ☐ Planned shutdowns, unexpected downtime and emergency call-outs.

Financing and lifetime costs

• ☐ Loan fees, interest during construction, repayment schedule and financing charges.
• ☐ Grant eligibility, payment timing and any conditions or repayment obligations.
• ☐ Major replacements, including engines, membranes, pumps and other equipment.
• ☐ Equipment life, end-of-life removal and site restoration allowances.

Revenue and budget checks

• ☐ Use net saleable energy after the plant’s own consumption and downtime.
• ☐ Confirm energy prices, heat use, gate-fee contracts and digestate income or savings.
• ☐ Check eligibility and duration of any assumed support payments.
• ☐ State currency, price date, inflation assumptions, tax treatment and quotation validity.
• ☐ Record every supplier exclusion and allocate its cost elsewhere in the budget.
• ☐ Test construction overruns, lower gas yield, lower revenue and higher running costs.
• ☐ Avoid counting the same income or saving twice. Keep operating costs, capital replacements and financing cash flows distinct.

Final check: every relevant item should have either a supported allowance or a documented reason for exclusion. This is a starting template; add costs specific to your site, technology and permit requirements.

What information does a supplier need?

Prepare annual and seasonal feedstock quantities, composition and laboratory information where available; site constraints; the intended gas use; connection requirements; and the digestate outlet. Request a written scope, exclusions, performance assumptions, maintenance requirements and delivery programme.

For smaller projects, see our small-scale anaerobic digestion guide. For gas-use choices, read about biogas upgrading technologies. You can also contact us to discuss an AD cost-estimating brief.

Frequently asked questions

How much does it cost to build a biogas plant?

The cost depends on capacity, feedstock treatment, location and gas-use equipment. Define a complete installed scope and obtain project-specific quotations. The reported examples above illustrate particular projects, rather than a price list for all biogas plants.

Can I use a US dairy calculator for a UK project?

It can help explore scenarios if the configuration fits, but local currency, prices, construction costs and market assumptions must be replaced. Check the model’s suitability with an adviser before relying on its outputs.

Are old published digester prices still useful?

They can explain historical projects and cost categories. They should retain their original dates and scope, and should not be presented as current offers.

Historical material and further reading

Earlier versions of this article discussed UK economics from 2005 and US farm examples from 2015. Those findings describe their original periods and assumptions; they do not establish present-day profitability. This revision replaces undated headline ranges with identified examples and an estimation method.

Further guidance: EPA project planning and financing and the WSU calculator and user guide.

[Published November 2014. Rewritten October 2026.]