Methane and greenhouse gas monitoring means using instruments that measure methane and carbon dioxide in the air directly, together with software that turns the readings into emissions reports. Methane is the main gas in natural gas, and it warms the planet far more than the same weight of carbon dioxide. It leaks from gas pipelines, wells, landfills and coal mines.
Most companies' emission figures are estimates, worked out from what they spent and from averages. A measurement is different from an estimate, because it starts from the gas actually in the air. The main demand for measurement comes from outside India. In the United States and Europe, rules on oil and gas companies, and on gas imported into Europe, ask operators to show measured methane leaks. India does not yet have a comparable rule for pipeline leaks, and its new carbon market asks mostly for estimates. So in India the buyers are fewer: gas pipeline and city gas companies, oil fields, landfill operators and research groups, and some who sell gas or goods to foreign customers.
An instrument called an analyser draws in a sample of air and measures how much of each gas it holds. Some analysers sit at a fixed point, such as the edge of a plant. Others are fitted to a vehicle, a drone or an aircraft and are moved along a pipeline or around a site. The software combines the gas readings with wind speed and direction, to work out where a leak is and how large it is.
Imagine a gas pipeline operator in Assam that drives a van with an analyser along its pipeline. Normal outside air holds about 2 parts of methane per million. Near one valve the reading rises to 20 parts per million. The software marks that spot on the map, so a repair team can visit the valve. A leak that is repaired also stops the loss of gas that the operator would have sold.
The measured figure then replaces an estimate in carbon accounting software. A wider view comes from earth observation satellites, which can spot large leaks from space, and the analyser is then used to check the leak on the ground. What is measured is counted under Scope 1, 2 and 3 emissions, and the whole area is described in sustainability management.