How much does an Anaerobic Digester cost to construct, commission and run? That's the vital question for AD utilisation on manure management projects on farms.
If the sum of these costs is known and the price payable for the outputs in energy and biofertiliser available to any farm business they will be able to work out the ROI. How long an AD plant investment will be likely to pay back, is the crucial question we try to answer here.
When we published the first edition of this page back in 2013 we said:
- For the right farm business or operator of any process which produces as a by-product a consistent organic waste, an anaerobic digester producing biogas coupled to a generator can be an excellent long-term investment;
but, subsequently, the cost of solar and wind turbine based energy has fallen and it makes no sense to compete with these other cheaper (admittedly not reliable 24/7) options. Now, in 2021 we say:
- Add a system to upgrade the quality of the biogas and produce biomethane and you will gain both a huge market to sell your energy into, and a market for transport fuel especially, which is growing more rapidly than new AD capacity can ever hope to match.
The following is our article as first published in December 2013. It remains relevant as it concentrates on providing sources of Anaerobic Digester Cost data and Calculators:
Anaerobic Digester Cost Data and Calculators (2013)
The best examples of implementing an anaerobic digester can mean a facility pays nothing for fuel. Facilities that need to replace a life-expired electric generator set should consider all options, and include a biogas digester model within their energy options. The decision should ultimately be based on what works best for a particular site and operator when the balance between investment risk incurred by adopting an Anaerobic Digestion process, against the benefits.
But, unfortunately, finding anaerobic digestion cost data to help put a price to the power over a set payback period is as hard as ever.
Looking to Government Bodies Who Provide Information on their view on Anaerobic Digestion costs, does not lead to in-depth analysis. We concentrated on finding costs for so-called “manure management” biogas plants, and we found the following statements:
Cost estimates for installing anaerobic digester systems [given here] have been based on manure-fed on-farm digesters. The estimated cost for a digester alone is between $400 and $700 per 1000 pounds of livestock weight to install. For dairy farms producing electricity, the installed cost is estimated at $800 to $1200 per cow for anaerobic digester system installation. The engine-generator can be up to half the cost of the project. Besides installation, it is important to consider insurance, operation and maintenance costs. Annual operation and maintenance costs can range from $11,000 for a small digester to $51,000 for a large system.
The U.S. E.P.A.’s AgSTAR program has advised that anaerobic digester installation may not be economical for farms with less than 500 animal units (an animal unit is defined as 1000 pounds live weight), based on energy payback and using solids for bedding or selling as a soil amendment. If generating electricity, the electricity purchase price will have a large influence on the payback rate. Most systems can not be justified on producing electricity alone. Avoided costs of using digested solids as bedding and off setting some heating costs are usually necessary to justify the investment. As anaerobic digester technology continues to improve, it may become more feasible to install anaerobic digester systems on smaller farms.
An anaerobic digester system does not run itself, it is not self-maintaining. [There are additional costs.] The system requires continuous monitoring, which is often done using computer-operated sensors. An anaerobic digester system requires temperature and pH regulation, as well as feedstock consistency. It will usually require 30 minutes to an hour per day to make adjustments and perform maintenance. Most systems that have failed were in part because of a lack of oversight and a person to champion the system.
Agstar Themselves Say:
The profitability of a biogas digester depends on the size of the operation, the method of manure management and local energy costs. According to AgSTAR, biogas recovery can be profitable and most effective at existing operations of at least 500 cows or 2,000 swine. Manure should be collected frequently (at least once a week) in a liquid, slurry or semi-solid state. Any electricity that is not used on-site can usually be sold to the local utility.
and Agstar also provides the following table of manure management anaerobic digestion costs:
In addition to the above, we have found some examples of press releases that provide at least some indication of the cost of their Anaerobic Digestion Plants and may be worth reading in full to find information about individual biogas project costs.
The small city of Junction City is home to Oregon's first anaerobic digester, at the family-owned and run Lochmead Farms. Although not an incredibly new technology, Lochmead Farms, a dairy producer, is truly a frontrunner in green dairy technology in Oregon. The digester captures methane gas from cow manure and burns it in a turbine to create power. The anaerobic digester cost $2.2 million and was built by Revolution Energy Solutions of Washington, D.C.
The digester creates 1.5 million kilowatt-hours of electricity, enough to power 300 homes each year. So much energy is produced that there is enough to sell some to a local public utility. The dairy farm itself, which was founded in 1941, has been at the cutting edge in alternative energy sources as well as local food and vertical business integration. The farm is building solar panels and produces 80 percent of the hay for its dairy cows.
On 26th August 2013, the second biogas plant at the Viessmann Company’s headquarters in Allendorf (Eder) was inaugurated. The first biogas plant went into operation three years ago.
The new wet fermentation plant built by its subsidiary, Schmack Biogas, cost around €7 million. The biogas plant produces 1.5 million cubic metres of biogas annually, enough to provide about 1,650 households with electricity and 370 households with heat.
This article has so far admittedly, not yet provided an abundance of data on the cost of biogas digesters for manure management. We thought this while writing and tried searching for an “anaerobic digester calculator” by using the Google search engine, and while wondering whether our readers might be able to calculate their costs that way we discovered that such calculators do exist.
First, we found an interactive Excel spreadsheet calculator. This one is an alternative method for assessing the viability of an on-farm biogas digester and is available to members of the National Non-Food Crops Centre (NNFC} which you can join for a charge. There are two membership levels. Non-members can also buy this but at an increased price.
Follow the following link below for more information: www.nnfcc.co.uk
Other biogas digester cost calculators are also available at:
End of Article first published December 2013