What It Actually Costs to Destroy a Ton of Methane

A 2,000-cow dairy in Wisconsin's Fox Valley produces roughly 8,000 tons of CO2 equivalent in fugitive methane every year. That methane can be destroyed two ways. An enclosed flare, installed on-site for $350,000, burns it at 98% efficiency for an annualized cost of roughly $12 per ton of CO2e. An RNG upgrading facility, built for $12 million with a pipeline interconnection, captures and processes the same gas at a delivered cost north of $80 per ton of CO2e after accounting for methane slip, transport losses, and capital recovery.

Both approaches reduce atmospheric methane. One costs six to eight times more than the other. Federal and state climate programs almost exclusively fund the expensive option.

Where the Numbers Come From

The cost-per-ton calculation for methane destruction is straightforward in theory but rarely performed in practice. RNG developers report project economics in terms of gas output, credit revenue, and investor returns. They do not typically report cost per ton of CO2e avoided, because the number is not flattering.

Here is how the math works for each approach.

An enclosed flare serving a mid-size dairy costs $200,000 to $500,000 installed, depending on gas flow and site conditions. Operating costs run $15,000 to $30,000 per year, primarily for monitoring and maintenance. With a 15-year useful life and no salvage value, the total lifecycle cost falls between $425,000 and $950,000. Destruction efficiency runs 98% or higher, meaning virtually all captured methane is converted to CO2 and water vapor on-site.

For a site producing 5,000 to 10,000 tons of CO2e per year in methane, the cost per ton destroyed lands between $8 and $25. The median across published case studies is approximately $15.

The RNG Side of the Ledger

An RNG upgrading facility at a comparable dairy costs $8 million to $25 million, depending on scale and technology. Annual operating expenses, including gas conditioning, compression, pipeline injection fees, and credit market administration, run $800,000 to $2 million. Capital recovery over a 20-year project life adds another $600,000 to $1.5 million per year, depending on financing terms.

Total annual costs for a mid-scale dairy RNG project typically range from $1.4 million to $3.5 million. Gas output from a 2,000-cow operation runs roughly 100,000 to 200,000 MMBtu per year.

But the methane destruction question is about atmospheric impact, not gas production. And here is where the comparison turns. RNG facilities report capture rates of 85% to 95%, but methane slip through processing, compression, and pipeline transport reduces net destruction efficiency to 72% to 90%. EPA's own reporting protocols acknowledge slip rates of 1% to 3% at the upgrading stage alone, with additional losses at compression, dehydration, and injection points.

When you recalculate the RNG project's climate benefit using net destruction rather than gross capture, the effective cost per ton of CO2e avoided climbs to $50 to $150. Projects at the smaller end of commercial viability, those processing gas from 1,000 to 2,000 cows, consistently land above $100 per ton.

Why the Gap Persists

If enclosed flares destroy methane at one-sixth the cost per ton, the logical question is why policy does not favor them. The answer has more to do with revenue models than atmospheric outcomes.

RNG produces a commodity: pipeline-quality methane. That commodity generates revenue through three stacking credit mechanisms: the federal Renewable Fuel Standard (RINs), California's Low Carbon Fuel Standard (LCFS), and the Inflation Reduction Act's 45Z clean fuel production credit. A well-positioned RNG project can generate $15 to $30 per MMBtu in stacked credits on top of the commodity gas price.

Enclosed flares produce no commodity. They destroy methane and emit CO2 and water vapor. There is no federal credit for methane destruction. Only three states offer any form of destruction incentive, and those programs are small, underfunded, and difficult to access.

The result is a policy architecture that rewards the expensive approach because it creates a tradeable asset, while ignoring the cheap approach because it merely solves the atmospheric problem.

Scale Changes the Math, but Not the Conclusion

RNG advocates correctly point out that costs per ton improve at scale. A 10,000-cow cluster dairy or a large municipal wastewater facility can achieve costs in the $30 to $50 per ton range, narrowing the gap with enclosed flares.

But scale cuts both ways. The EPA estimates there are roughly 8,000 dairy and swine operations in the United States with sufficient methane output to warrant some form of destruction technology. Fewer than 400 of those sites are large enough to support commercial RNG economics. The remaining 7,600 sites sit below the threshold where RNG pencils out, even with full credit stacking.

For those 7,600 sub-scale sites, the cost-per-ton question is not a close call. Enclosed flares at $10 to $20 per ton versus no action at all, because the only funded alternative requires a scale they cannot reach.

The aggregate climate math is similarly one-sided. Deploying enclosed flares at 5,000 sub-scale sites would cost roughly $1.5 billion to $2.5 billion in total capital and destroy an estimated 40 to 50 million tons of CO2e per year. Achieving the same atmospheric reduction through RNG at commercial-scale sites would require $40 billion or more in capital deployment and would still leave the sub-scale sites unaddressed.

The Number That Should Drive Policy

Climate programs exist to reduce atmospheric greenhouse gas concentrations at the lowest possible cost to society. The metric that should drive methane policy is cost per ton of CO2e avoided, calculated on a net basis after accounting for all system losses.

By that metric, enclosed flaring is the most cost-effective methane destruction technology available today. It is not close. RNG has a role at large-scale sites where the economics work without excessive subsidy. But directing billions in ratepayer and taxpayer funds toward RNG at sites where enclosed flares could do the job for a fraction of the cost is a policy failure measured in both dollars and emissions.

The data exists. The comparison is not complicated. What is missing is a willingness to let the cost-per-ton number guide the policy conversation instead of the credit-revenue number. Until that changes, we will keep funding the expensive way to do what a simpler technology already does better.