Measurement Equipment

Flow meters for carbon project field work

Calibrated gas flow measurement for biogas, landfill gas, and anaerobic digester projects. What to look for, what we recommend, and how to meet methodology accuracy requirements.

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For biogas, landfill gas, anaerobic digester and cookstove projects, accurate flow measurement is central to your MRV methodology. Thermal mass flow meters are the standard — they measure mass flow directly without needing additional temperature or pressure compensation, and they handle the wet, dirty conditions typical of biological gas sources.

Verification bodies expect NIST-traceable calibrated instruments. Make sure any meter you purchase ships with a calibration certificate, and budget for recalibration at intervals required by your methodology — typically every 12 months.

Top Pick
Portable Biogas & Methane Measurement
Alicat Scientific Portable Mass Flow Meter

The industry benchmark for portable methane measurement. Measures across a wide operating range — 1% to 100% of full scale — with sub-10ms response times and accuracy to ±0.8% of reading. Anticorrosive construction handles the wet, dirty conditions of biogas and landfill gas environments. Widely used by monitoring contractors on EPA and Verra-regulated projects worldwide.

±0.8% accuracyAnticorrosive bodyWide turndown ratioMethane & biogasCalibration certificate

Alicat meters ship with NIST-traceable calibration certificates as standard — important for Gold Standard and Verra VCS MRV submissions where auditors will ask to see instrument documentation.

Approx. price£1,800–£3,500
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Professional
Fixed Installation — Anaerobic Digesters
Fox Thermal FT4A Biogas Flow Meter

Purpose-built for biogas and digester gas monitoring. Handles the wet, corrosive mixed-gas environment of anaerobic digesters — typically 70% methane, 30% CO₂ with H₂S traces. Features CAL-V calibration validation so you can verify the meter is still in original calibration without removing it from the pipe, which is valuable for continuous monitoring projects requiring audit trails.

Digester-grade corrosion resistanceCAL-V in-situ validationDirect mass flowMethane & CO₂Wide flow range

The CAL-V feature allows you to demonstrate calibration integrity to a VVB without interrupting monitoring — important for projects where continuous data coverage is a methodology requirement.

Approx. price£2,200–£4,000
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Budget Option
General Gas Flow — Smaller Projects
Tactical Flow Meter TFM-5700

A thermal time-of-flight meter for methane and natural gas at a more accessible price point. Uses MEMS sensor technology inside a laminar flow channel — highly accurate at low flow rates without needing external compensation. Good for smaller projects during development and feasibility phase before committing to full MRV instrumentation.

MEMS sensorAccurate at low flow ratesNo pressure compensation needed½" to 2" NPT fittings

More accessible price for early-stage monitoring. Suitable during feasibility and project development phases, or for smaller projects where a lower-cost instrument still meets methodology accuracy thresholds.

Approx. price£600–£1,200
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Common questions

What flow meter accuracy does Gold Standard require for biogas projects?
Gold Standard methodology AMS-III.R typically requires flow measurement accuracy of ±5% or better. Verra ACM0010 and similar methodologies usually require ±2–5% depending on the project type. Always check the specific version of your methodology — accuracy requirements can vary between versions and project scales.
Do I need an ATEX-certified flow meter for biogas sites?
Yes, if your installation is in a classified hazardous zone (Zone 1 or Zone 2 under ATEX). Biogas production areas are typically classified Zone 2 at minimum. Check with your site safety engineer and ensure both the meter and any transmitters carry appropriate ATEX or IECEx certification for the zone classification.
How often do flow meters need recalibrating for carbon project MRV?
Most methodologies require annual recalibration with a NIST-traceable certificate. Some require more frequent calibration if the meter is exposed to corrosive gases. Build recalibration costs into your project economics from the start — typically £200–600 per instrument per year depending on the meter and calibration lab.

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