Use this Biogas Calculator for Assessing Your Potential On-Farm Biogas Digester Yield
(Updated November 2011)
Are you wondering whether your farm would be a suitable location for an On-Farm Anaerobic Digestion Plant, based on the use of the farm’s own manure as the feedstock?
This simple online biogas calculator will give you a very approximate assessment of the likely biogas yield in cubic metres per year.
If you then alsoadd your estimated payment for the exported electricity in pence/kilowatt hour which will be:
at least 12p/kWh from the Feed in Tarrif payment (UK)
according to the UK Energy Bill the revenue will possibly also include a ROCS paymentof at least 4 p/kWh* (subject to acceptance of the digester into the scheme by Defra/Decc).
your annual income from biogas will be shown.
This income is not profit and it would need to be used to pay the AD Plant’s construction costs and its operation and maintenance costs. However, the idea is to make the point that there is substantial real income from producing power from biogas under current UK government incentives.
Please Note! All those that use of our calculator below, and the spreadsheet download on this page - during testing and until further notice - must treat both as provided for test and development purposes only, until the output they gives has been tested fully.
* - this amount will rise after Energy Bill implementation later in 2009.
Free Biogas Calculator Plus Free Downloadable Spreadsheet Version
New Software Biogas Calculator for December 2011!
We are improving and extending the use of our highly popular biogas calculator.
Please use the feedback form to contact us if you are interested in discussing sponsorship.
Scroll down and find out how much revenue you can make from electricity sales, if you install a biogas plant!
You can also use our spreadsheet version of the biogas calculator above, for a more detailed assessment of your farm biogas project’s economic feasibility, and you will see the various assumptions made at each of the stages used in the assessment.
Download the above calculator as a spreadsheet .odt file suitable for use in the Open Office (www.openoffice.org) spreadsheet application.
The calculator higher on this page is based upon, the same method of calculation, but the spreadsheet version can be used to create a more sophisticated assessment.
Number of downloads of the biogas calculation sheet since 2 April =
Please Note! This spreadsheet is still in development and is also a Draft version. It may contain multiple errors.
We recommend that you also download the Defra (United Kingdom) Report here in which the many assumptions which have been used are documented (see Appendix 4),and which have been made about the efficiency of the plant. Other variables exist in the calorific value of the manure used etc. All the many factors used in combination have resulted in the conversion factors we have used in the simple biogas calculator above.
Additional Data for Biogas Calculations
The following biogas yields per tonne of anaerobic digestion plant feedstock material are taken from Table 4. 2 of the booklet “Anaerobic Digestion” published by the IWM Anaerobic Digestion Working Group 1998.
Gas yield in m3 per tonne Total Solids (TS)
Solids Content %
Household and commercial waste
MSW (30% Biodegradable)
Paper and cardboard
Hotels and restaurants
Alcohols: ethanol, methanol
Liquid concentrates: sugar, glycol
Liquid wastes: beer, cultures
Solid wastes: tobacco, food processing
Cattle (fresh farmyard)
.4 (per animal/day)
Pigs (fresh farmyard)
.1 (per animal/day)
.01 (per animal/day)
As slurries - typically
Energy equivalents used in biogas calculations:
1 Watt = 1 joule second-1
1 Wh = 1 x 3600 joules (J)
1 kWh = 3600000 J
1 kWh = 3.6 MJ
22 MJ is the commonly accepted energy value for 1m3 biogas)
22 MJ = 22/3.6 kWh
= 6.1 kWh
But we must allow for the electrical conversion efficiency = 35%