How Landfill Gas to Energy Works, and When a Data Center Fits

Every landfill that holds household waste makes gas. Bacteria break down food, paper and yard waste and give off a mix of methane and carbon dioxide. Larger landfills are required to collect and control it. The open question for an owner is what to do with it: burn it in a flare, sell electricity, sell the gas, or find a single large buyer on site.

This guide walks the landfill gas to energy process from well to meter, using the US Environmental Protection Agency's Landfill Methane Outreach Program (LMOP) as the main source. It shows how to estimate what your site can make, why output declines, and how the common uses compare. It ends with an honest look at when a data center is a sensible buyer. For many landfills, it is not.

How does the landfill gas to energy process work?

Gas is pulled out of the waste through wells, cleaned of water and contaminants, then burned in engines or turbines, piped to a nearby user, or upgraded to pipeline-quality gas. The EPA describes the raw gas as roughly 50 percent methane and 50 percent carbon dioxide, with small amounts of other compounds.

1. Collection. Vertical wells or horizontal trenches are placed in the waste and joined by a network of pipes. A blower or vacuum pulls the gas to a central point.
2. Treatment. The gas is dried and filtered to remove water, particles and other impurities. Some sites also need to remove siloxanes and sulfur compounds, which damage engines. That adds cost.
3. Use. Treated gas fuels engines, turbines or microturbines that make electricity. It can also go by pipe to a boiler, kiln or furnace nearby. Or it is cleaned much further, mostly by removing carbon dioxide, and injected into a natural gas pipeline as renewable natural gas (RNG).
4. Flaring of the rest. A flare burns any gas the project can't use, and all of it during outages.

Landfill gas has about half the energy content of pipeline natural gas, around 500 Btu per standard cubic foot according to the EPA's project development handbook. Equipment has to be set up for that lower-grade fuel.

What are the main landfill gas to energy systems?

Most landfill gas power plants use reciprocating engines. The EPA's LFG Energy Project Development Handbook says more than 85% of landfill gas electricity projects in 2021 used internal combustion engines. These are a good match for projects from 800 kW to 3 MW, and several engines can run side by side for larger sites.

• Reciprocating engines. The default. Proven, efficient, and engines can be added or removed as gas flow changes.
• Gas turbines. Used on large projects, usually 5 MW or more. They need a bigger, steadier gas flow.
• Microturbines. Single units of 30 to 250 kW, used for projects under 1 MW or at the tail end of a site's gas life.
• Combined heat and power. Any of the above, with the waste heat used nearby.

The same engines that make power for the grid can make power for a load on site. That is how a behind-the-meter data center would use landfill gas: the electricity goes straight to the building instead of out through a utility meter.

How much electricity does a landfill make?

As a rule of thumb, the EPA estimates that every million tons of municipal solid waste in place makes about 300 cubic feet per minute of landfill gas. That is enough for roughly 0.78 MW of power. By that rule, a site holding 10 million tons might support around 8 MW. That figure is our arithmetic, and it assumes the gas is actually collected.

Collection is the catch. The handbook puts collection efficiency at fully covered landfills at 50 to 95 percent, with 75 percent the usual assumption. Sites still taking waste often have open areas without wells.

The EPA's first screening questions show which landfills are likely to make enough gas for a project:

• At least 1 million tons of municipal solid waste in place
• A depth of 50 feet or more
• Open, or recently closed
• At least 25 inches of rain or snow a year, since moisture speeds decay
• Enough organic waste. Construction and demolition landfills make little gas
• A gas collection system already in place, which gives real flow data

For a real number, model your site with the EPA's free LandGEM tool and check it against measured flow. To see how a few megawatts compares with large buyers, see how much power a data center uses.

How does landfill gas output change over time?

Gas output rises while waste keeps arriving, peaks around closure, then falls year after year. Under the EPA's LandGEM model, each year's waste makes the most methane soon after it is placed, then decays exponentially as bacteria use up the organic material.

Waste keeps producing gas for as many as 20 to 30 years after it is landfilled, according to the handbook. Wet sites decay faster, so they peak higher and decline sooner. Dry sites make less gas but stretch it out.

This shape decides which buyers make sense:

• An open landfill with years of capacity left has rising or steady gas. It can support a long contract.
• A recently closed landfill is near its peak. Output is high now but will fall, so any contract has to plan for less gas each year.
• A landfill closed for many years has gas that is low and still declining. It suits small, flexible equipment, or a flare.

Owners handle decline by retiring engines as flow drops or by blending in another fuel. A buyer who needs the same power every hour for years has to plan for this from day one.

Which landfill gas to energy projects pay off: power, RNG or direct use?

Electricity is still the most common use, but it isn't always the best one. As of September 2024, the EPA counted 542 operational landfill gas energy projects in the United States. About 63% generate electricity, about 20% make renewable natural gas, and about 17% send medium-Btu gas directly to a nearby user. The EPA also lists 444 candidate landfills that could support a project but have none.

Which use pays best depends on your gas flow, distance to a pipeline, local power prices, and the credit programs open to you. Those programs change, so check current rules with your advisors.

The table below compares the common landfill gas to energy projects, plus the option of a data center on site.

When is a data center a sensible buyer for landfill gas?

A data center makes sense when the landfill has a large, steady gas flow that will last for many years, the land around it can host a building, and fiber is in reach. It is a poor fit for most small or closed landfills.

The reason is the size and shape of the load. The International Energy Agency puts a conventional data center at around 10-25 MW and a hyperscale, AI-focused site at 100 MW or more. Compare that with a landfill that makes a few megawatts. Few landfills can power an AI site alone. Landfill gas more often covers part of a site's fuel, alongside pipeline gas, as our guide to gas-powered data centers explains.

A data center also runs around the clock for years and needs fuel it can count on for the whole lease, with backup. That favours landfills still filling, with a long permitted life ahead.

Signs a data center could fit your site:

• Several megawatts' worth of gas, collected and measured, with a forecast that holds or grows
• Years of permitted disposal capacity left
• Buildable land on or next to the site, outside the waste footprint
• Fiber within reach, and road access for heavy equipment
• A pipeline gas connection nearby that could back up or add to the supply
• No existing contract that already commits all the gas for years

If several of those are missing, RNG, a local power sale or direct use will probably serve you better. That is a fine answer.

What to check before you sign a gas or land deal

A gas deal and a land deal are often signed together, so read them together.

• Volume terms. Does the buyer take a fixed amount or only what it needs, and what happens when your flow falls short?
• Rights to the gas. Does an existing contract or credit agreement already claim the gas or its environmental attributes?
• Collection duties. Who runs and expands the wellfield? Poor collection lowers output and can create compliance problems.
• Land and term. Where would the building sit relative to future cells and closure plans, and does the contract length match your gas forecast?

For the land side, our guide to selling or leasing land to a data center covers options, letters of intent and red flags. This guide is general information, not legal, tax or regulatory advice.