Landfill Gas Mining

U.S. EPA, the US Environmental Protection Agency, uses LFG for landfill gas. It forms as organic material decomposes; methane is produced mainly in the absence of oxygen. The gas is roughly half methane, chemically CH4, and half carbon dioxide, CO2, with other constituents. That is an approximate composition by volume, not a guaranteed recipe for every landfill. A reported volume of landfill gas therefore does not automatically mean the same volume of pure methane. For a fuel supply, this distinction matters. Methane is also a greenhouse gas: if it escapes into the atmosphere, it contributes to trapping heat. Losing it therefore means more than losing usable fuel. [1]

Wells or horizontal collectors and pipes gather the gas, but the system does not capture everything. U.S. EPA therefore distinguishes estimates of gas generation from estimates of recoverable gas. LandGEM models gas generation; it is not a flow meter at the generator’s inlet. Its output must be combined with an assumed collection efficiency. Collection-system coverage, equipment condition and measurement quality determine whether the estimate fits reality. A model’s number is not an amount automatically delivered to the engine. [2]

Wet gas containing impurities cannot simply be sent to any engine. U.S. EPA describes moisture removal and, as needed, removal of siloxanes—silicon-containing compounds—sulfur compounds and other impurities. Treatment depends on the gas and the equipment. Preparing gas for electricity generation is not automatically the same as producing RNG: renewable natural gas upgraded to a quality suitable for replacing natural gas, for example in pipelines. EIA, the US Energy Information Administration, explains this distinction too. Parking a mining container on site does not replace these steps. [1] [6]

Try our own simplified example: 100 kg of methane, or CH4, is produced, and collection captures 75 kg. The combustion equipment destroys 98 % of its input, or 73.5 kg. Its output contains 1.5 kg of unburned methane; 25 kg remained outside collection. Destroying 98 % of the equipment’s input does not mean destroying that share of all methane generated in the landfill. U.S. EPA distinguishes these efficiencies. This example is not an emissions inventory, a complete emissions account: oxidation in the cover, which transforms some methane, other leaks and changes in stored gas need separate consideration. Combustion converts methane into carbon dioxide and water. “Methane destruction” therefore does not mean that no gases leave the exhaust. [3] [4]

Methane Mitigation means reducing methane emissions. But the benefit of collecting methane is not evidence of zero local emissions. U.S. EPA points to NOx, nitrogen oxides formed during combustion that contribute to smog. Depending on the technologies compared, a landfill generator may emit more of them than the source it replaces. So ask separately about methane collected, combustion and electricity for miners. Adding an electricity customer cannot itself be credited with every benefit of gas collection that was already operating. [4]

Waste does not stop decomposing when mining becomes unprofitable. U.S. EPA describes continuing collection and burning gas in a flare, a device designed to burn off the gas, even after electricity production ends. A new mining operation may therefore replace an existing flare or another customer, rather than all the gas being released into the air. During a mining pause, track the actual gas flow and the blowers extracting it. Their electricity use and maintenance do not disappear just because the machines at the end of the chain have stopped. [3]

Uptime is the share of time the equipment being monitored is actually working or available; define exactly what is measured. U.S. EPA’s gas forecasts use disposal history, waste composition and local conditions. Overestimating future waste deliveries or overlooking incomplete collection can overstate available fuel. Compare the model with measured recovery and operating records. Continuing decomposition does not mean that the generator, treatment plant and miners all run continuously. A long-term forecast and the availability of one machine answer different questions. [2]

U.S. EPA separates an initial economic estimate from a detailed assessment of a particular landfill. For mining, count not just miners but collection, gas treatment, the generator, auxiliary electricity and servicing. Compare realistic alternatives: electricity for another customer, direct energy use of the gas or upgrading it to RNG. Only then can a payback conclusion be meaningful. Establish profit and any additional emissions benefit separately. Without that comparison, “Bitcoin from rubbish” remains an interesting idea rather than an evaluation of the project. [5]