Odorant Testing for RNG and Biogas Producers: What Interconnection Requires
- 1 day ago
- 3 min read
Updated: 23 hours ago
Renewable natural gas and biogas producers face a version of the odorization problem that traditional natural gas operators rarely have to think through from scratch: proving, at the point of pipeline interconnection, that the gas entering the system is odorized to the same detectable standard as the rest of the network. For a new RNG facility, that isn't a formality. It's usually a hard gate in the interconnection agreement, and getting it wrong can delay a project that has already taken years to permit and build.
Why Interconnection Odorant Verification Is Different for RNG
Most pipeline operators odorize gas once, upstream, and rely on the pipe wall and flow conditions to keep that odorant detectable downstream. RNG and biogas producers are usually injecting into an existing distribution or transmission system at a single point, which means the interconnecting utility needs direct, field-verified proof that the gas meets odorant concentration requirements at the moment it enters their system, not an assumption based on upstream conditions elsewhere in the network. That verification typically has to happen at commissioning and then periodically afterward, and it has to be documented in a form the receiving utility will actually accept.
Common Challenges in RNG and Biogas Odorant Testing
Biomethane upgraded from landfill gas, digester gas, or other biogas sources doesn't always behave like pipeline-quality natural gas at the sensor level. Depending on the upgrading process, trace contaminants, moisture, and inconsistent flow rates, especially during startup or low-production periods, can all affect how reliably an odorant reading holds up. A few practical issues come up repeatedly:
Flow can be intermittent or low-volume, especially at smaller digester-based facilities, which changes how odorant distributes through the interconnection point
Gas composition can vary batch to batch depending on feedstock, which affects how odorant is absorbed or diluted
The receiving utility may specify a particular odorant blend or concentration standard that differs from what the producer's own equipment was originally calibrated for
What a Field Analyzer Needs to Confirm at Interconnection
At minimum, verification at an RNG or biogas interconnection point should confirm:
Odorant concentration in parts per million, measured directly at or near the interconnection point
Consistency of that reading across varying flow conditions, not just a single spot check
Calibration traceable to a certified standard gas, since a utility reviewing your documentation will want to know the instrument itself was verified, not just the gas
Results captured in a form, timestamped and exportable, that can be handed to the receiving utility or regulator without additional work
Choosing the Right Testing Approach
For a first-time interconnection, testing usually needs to happen at commissioning and then on a recurring schedule afterward; the exact frequency is typically set in the interconnection agreement itself.
A portable odorant analyzer built for field use, rather than a fixed lab instrument, lets a producer run and document these checks without shipping samples out or waiting on a lab turnaround, which matters when a delayed reading can hold up gas flow. If the interconnection also involves a new pipeline segment on the producer's side, that segment may need its own conditioning process before startup to avoid odor fade complicating the first verification reading. See our overview of
pipeline pickling and conditioning for how that process works.
Building Compliance Documentation From Day One
Because RNG interconnection agreements are often reviewed periodically, and can be revisited if a utility has any concern about odorant levels, it's worth treating documentation as part of the testing process itself, not something assembled after the fact. That means logging concentration readings, calibration records, and testing dates in a consistent format from the very first commissioning test, so that if a utility or regulator asks for a testing history two years into operation, it already exists in a usable form.
If you're bringing a new RNG or biogas facility to interconnection and need a practical way to verify and document odorant levels in the field, our portable odorant analyzer was built specifically for this kind of work, and we can help you think through the testing plan before you're standing at the tie-in point.