Training guide
What the FMS questionnaire is for
The Fuel Measurement and Sampling (FMS) questionnaire sets out the procedures you will follow to determine eligible biomethane and to meet the sustainability reporting requirements of the non-domestic RHI scheme.
Submission and approval of the FMS forms part of the RHI accreditation process. Accreditation cannot be granted until FMS procedures have been submitted and approved, and once accredited you must keep working to the procedures you described.
Keeping the FMS up to date is an ongoing obligation. Any change to consignments or practices must be reflected in the FMS, and an amended FMS must be emailed to rhi.biomass-sustainability@ofgem.gov.uk. Changes need to be reviewed and approved before you continue periodic data submissions.
The completed questionnaire goes in as a PDF alongside the RHI application, quoting the RHI number. Supporting evidence such as lab reports and GHG calculations goes by email.
Declaration
Declaration and signature
Confirms the information is correct to the best of your knowledge and that you will notify Ofgem when procedures or feedstocks change.
What Ofgem is looking for
- Signature of the authorised signatory of the biomethane producer
- A date on the signature
- Confirmation the signatory understands the duty to notify Ofgem of changes
Common mistakes
- Signed by someone who is not the authorised signatory — the document is returned, delaying review and the RHI application
- Undated signature blocks
- Sending an amended FMS without re-signing it
Worked example — Hemswell Biomethane
Signed by the authorised signatory on 21 January 2025 and submitted with RHI0000024078 quoted.
Section A
Installation information
General information about the installation. Answers must match the registration application exactly.
What Ofgem is looking for
- A.1 RHI number in full, e.g. RHI0000024078
- A.2 Installation name exactly as given in HA100 of the RHI application
- A.3 Maximum initial capacity (or maximum additional capacity for additional biomethane)
Common mistakes
- Using the site's trading name instead of the HA100 name
- Quoting a shortened RHI reference
- Capacity that does not tie back to the application
Worked example — Barnes Farm
RHI0000024090, installation name 'Barnes Farm (P0081)', maximum initial capacity 4,380,000.
Section B
Feedstock consignments
Lists every feedstock consignment used and determines its classification.
What Ofgem is looking for
- Every consignment listed with a reference, source and country of origin, classification, description and physical state
- EWC codes where the material is a waste
- B.2 reasoning for anything classified as waste or residue, ideally tied to Appendix 2 of the Sustainability Self-Reporting Guidance
Common mistakes
- Liquid consignments classified as products or residues — not permitted under the RHI Scheme Regulations
- Leaving a consignment off the list because it is only used occasionally
- Claiming a waste classification with no Appendix 2 reference or Ofgem correspondence to support it
Worked example — Bubwith (R100)
P0080_03 Argent glycerol is classified as waste on the strength of Ofgem correspondence dated 31/10/2023, with a weighted-average %MONG calculation applied whenever it is used in a quarter.
Section C
Assessing consignments
Explains how the quantity of each consignment used in a quarter is established.
What Ofgem is looking for
- C.1 whether consignments are mixed before entering the digester — this decides whether you answer C.2–C.5 or C.6–C.11
- Where measurement happens and with what equipment (weighbridge on entry and exit, for example)
- Stated accuracy as ±X%, plus calibration standard and frequency
- The feedstock records retained as evidence for each quarter
Common mistakes
- Answering both the unmixed and the mixed blocks, or neither
- Giving equipment but no calibration standard or frequency
- Saying records are 'kept' without saying what is recorded or where
Worked example — Bubwith (R100)
Vehicles cross a weighbridge on entry and exit; weights load into SAP with point of origin, distance travelled, EWC code, description and haulier. Weighbridge tested annually to the UK Weighing Federation code with a typical tolerance of ±20 kg.
Section D
Apportioning biogas yields to feedstocks
Splits the biogas produced across the feedstocks used. Skipped where there is only one consignment.
What Ofgem is looking for
- D.1 dry matter percentage and biogas yield per feedstock, with the source of each figure (literature, lab test, Ofgem conservative value)
- D.2 the apportionment route — the Ofgem RHI Biogas Apportioning Tool or an alternative
- D.3 a full description if an alternative tool is used
Common mistakes
- Leaving out ineligible feedstocks — they still need dry matter and yield figures so the deduction can be worked out
- Yield figures with no stated source
- Selecting the Ofgem tool but then describing a different in-house calculation
Worked example — Park Farm
Ineligible glycerol suppliers such as Alexander Scott Oils and Olleco Liverpool are listed at 21.10% dry matter and 508.8 biogas yield using conservative values provided by Ofgem, with apportionment through the Ofgem RHI Biogas Apportioning Tool.
Section E
Greenhouse gas emissions
Sets out how the GHG emissions of the biomethane will be calculated.
What Ofgem is looking for
- The calculation methodology selected
- Where a non-standard method is used, the proposed methodology emailed to rhi.biomass-sustainability@ofgem.gov.uk
Common mistakes
- Ticking 'other methodology' and never sending the method in for agreement
- Changing tool or emission factors mid-scheme without amending the FMS
Worked example — Hemswell Biomethane
'Other GHG calculation methodology' selected, with the proposed methodology sent to the biomass sustainability inbox for agreement.
Section F
Land criteria
Demonstrates land criteria compliance for feedstocks that are not wastes.
What Ofgem is looking for
- A compliance method for each consignment classified as a product or residue
- Evidence type, e.g. a certification scheme category or other evidence such as maps and land use records
Common mistakes
- Completing this section unnecessarily — if every consignment in Section B is a waste, it does not apply
- Skipping it when one consignment is actually a residue or product
Worked example — Local Generation Biomethane
All consignments are wastes, so Section F is left blank and the pack moves straight to Section G.
Section G
Measuring the energy of biomethane injected
Describes how volume and gross calorific value of the injected biomethane are measured.
What Ofgem is looking for
- Meter make, model and serial number, with an opening reading and the date it was taken
- How volume readings are corrected to standard temperature and pressure
- Any verification of the measurements, and the data source used for payment claims
Common mistakes
- Not declaring a meter change — a replaced fiscal meter is a change to your procedures and needs an amended FMS
- Volume readings not corrected to standard temperature and pressure
- Missing serial numbers, so readings cannot be tied to a specific meter
Worked example — Local Generation Biomethane
SICK FLOWSICK500 flowmeter, S/N 22280001, opening reading 0.799 on 22/08/2025 and 17,997.668 m3 on 02/09/2025 after the second replacement — both changes declared as an amendment.
Section H
Measuring the energy content of propane
Covers propane added to the biomethane for calorific value enrichment.
What Ofgem is looking for
- H.1 whether propane is added at all
- Meter details, opening readings, dates and serial numbers
- How the measurement is corrected and how often it updates
Common mistakes
- Confusing the telemetry reading with the physical meter reading
- Not stating the measurement phase and correction basis for the propane meter
- Answering the rest of Section H after ticking 'No' at H.1
Worked example — Park Farm
Endress+Hauser Cubemass coriolis meter S/N P818AB02000 updating every three to five minutes, with paired opening readings of 78.8724 kg and 149.7879 kg on 18/12/2019.
Section I
Measuring the heat to be deducted
Captures heat from an external source used at the biogas plant or to produce biomethane, which must be deducted.
What Ofgem is looking for
- How that heat is measured, or a clear statement that it is not applicable
- Heat meter opening readings, dates, serial numbers and what each meter measures
Common mistakes
- Leaving old heat meters in the table after the heat source has gone
- Writing N/A where an external boiler is genuinely feeding the digesters
Worked example — Park Farm
From 28/10/2022 no heat deduction applies to the eligible heat output calculation, because the diesel boiler feeding the digesters was replaced by a biogas boiler — recorded in the Additional Information section.
Ongoing
Keeping the FMS current
Your FMS must stay accurate for as long as you are on the scheme.
What Ofgem is looking for
- An amended FMS emailed to rhi.biomass-sustainability@ofgem.gov.uk whenever consignments or practices change
- Changes reviewed and approved before periodic data submissions continue
- The RHI number quoted on every submission and every piece of supporting evidence
Common mistakes
- Carrying on with quarterly submissions while an amendment is still unapproved
- Adding a new feedstock supplier without updating Section B
- Uploading to the register but never emailing the amendment
Worked example — Local Generation Biomethane
The fiscal flow meter was replaced on 22 August 2025 and again on 2 September 2025; both were written up as an amendment and the FMS re-signed on 19 September 2025.
Site reference cards
The details behind the scenarios and quiz answers.
RHI0000024078 · P0068 · capacity 2,080,500
Hemswell Biomethane
A food-waste fed AD plant injecting biomethane to grid, with propane enrichment. Six waste consignments, all unmixed before the digester.
Consignments
- P0068_01 Solid material waste from food manufacturersWaste — Materials unsuitable for consumption or processing. Solid, packaged/palletised/bulk. EWC 02 02 03, 02 03 04, 02 05 01, 02 07 04, 02 06 01
- P0068_02 Biodegradable kitchen & canteen wasteWaste — Food waste. Solid / palletised. EWC 20 01 08
- P0068_03 Mixed municipal wasteWaste — Mixed solid waste. Solid. EWC 20 03 01
- P0068_04 Sludges from washing, cleaning and biological treatment of industrial waterWaste — Sludges from food or industrial processes. Fluid / liquid. EWC 02 03 01, 02 02 01, 19 08 12
- P0068_05 DigestateWaste — Waste already processed via anaerobic digestion. Solid
- P0068_06 Animal tissue wasteWaste — Animal tissue waste. Solid. EWC 02 02 02
Key facts
- Mixed before digester?
- No — all consignments unmixed
- Biogas apportionment
- Ofgem RHI Biogas Apportioning Tool
- GHG method
- Other methodology, sent to Ofgem for agreement
- Propane added?
- Yes — Endress+Hauser Cubemass DCI, S/N M5015602000
- Heat deduction
- None recorded (Section I returned N/A)
RHI0000024090 · P0081 · capacity 4,380,000
Barnes Farm
Liquid food waste and wash water delivered by road tanker, plus digestate. Heat meters on the digesters are declared in Section I.
Consignments
- P0081_01 Liquid food wasteWaste — Liquid food waste, materials unsuitable for human consumption or processing. Bulk delivery via road tanker
- P0081_02 Food waste — wash waterWaste — Waste wash water from food manufacturer cleaning process. Bulk delivery via road tanker
- DigestateWaste — Waste already processed via anaerobic digestion. Solid
Key facts
- Mixed before digester?
- No
- Weighbridge
- Tested annually to UK Weighing Federation code, tolerance ±20 kg
- Biogas apportionment
- Ofgem RHI Biogas Apportioning Tool
- Propane added?
- Yes — Endress+Hauser Cubemass coriolis, S/N P4120802000
- Heat deduction
- Digester heat meters declared, S/N 23923057
RHI0000024245 · P0012 · capacity 1,861,500
Local Generation Biomethane
Food-waste AD plant whose fiscal flow meter was replaced twice in 2025 — the FMS was amended and re-submitted to record the change.
Consignments
- P0012_01 Solid material waste from food manufacturersWaste — Materials unsuitable for consumption or processing. Solid, packaged/palletised/bulk. EWC 02 02 03, 02 03 04, 02 05 01, 02 07 04, 02 06 01
- P0012_02 Biodegradable kitchen & canteen wasteWaste — Food waste. Solid / palletised. EWC 20 01 08
- P0012_03 Mixed municipal wasteWaste — Mixed solid waste. Solid. EWC 20 03 01
- P0012_06 Animal tissue wasteWaste — Animal tissue waste. Solid. EWC 02 02 02
Key facts
- Mixed before digester?
- No
- Fiscal meter
- SICK FLOWSICK500, S/N 22280001
- Meter change
- Replaced 22 August 2025 and again 2 September 2025
- Declared amendment
- Recorded in the Additional Information section of the FMS
- Heat deduction
- Not applicable
RHI0000024378 · P0092 · capacity 1,971,000
Park Farm
Liquid food waste, wash water and Argent glycerol. Certain glycerol suppliers are treated as ineligible and drive an eligible heat output deduction.
Consignments
- P0092_01 Liquid food wasteWaste — Liquid food waste, materials unsuitable for human consumption or processing. Bulk delivery via road tanker
- P0092_02 Food waste — wash waterWaste — Waste wash water from food manufacturer cleaning process. Bulk delivery via road tanker
- P0092_03 Argent glycerolWaste — Waste glycerol; some producers unevidenced and treated as ineligible. Liquid
Key facts
- Ineligible suppliers
- Alexander Scott Oils, Olleco Liverpool and others listed at 21.10% dry matter, 508.8 biogas yield
- Biogas apportionment
- Ofgem RHI Biogas Apportioning Tool
- Propane added?
- Yes — Endress+Hauser Cubemass, S/N P818AB02000
- Fiscal meter
- SICK flowmeter, S/N 19200343
- Heat deduction
- From 28/10/2022 no heat deduction — the diesel boiler was replaced by a biogas boiler
RHI0000024335 · P0080 · capacity 1,971,000
Bubwith (R100)
Liquid food waste, wash water and Argent glycerol. Glycerol needs a %MONG calculation on a weighted-average basis to establish fossil contamination.
Consignments
- P0080_01 Liquid food wasteWaste — From food manufacturers, restaurants and kerbside household collections — over-production or out-of-date product. Liquid, bulk tanker
- P0080_02 Food waste wash waterWaste — From food manufacturer cleaning water treatment facilities. Liquid, bulk tanker
- P0080_03 Argent glycerolWaste — Approved as waste by Ofgem correspondence dated 31/10/2023. Liquid
Key facts
- Mixed before digester?
- No
- Feedstock capture
- Weighbridge in and out, recorded in SAP with origin, distance, EWC and haulier
- Weighbridge accuracy
- ±20 kg, annual test to UK Weighing Federation code
- Glycerol treatment
- Weighted-average %MONG calculation each quarter it is used
- Ineligible producers
- Eleven listed suppliers subject to an EHO deduction