Waste and Leakage🔗

Change the level of adoption of emissions best practices related to waste, energy, and industry. Methane (CH₄) and nitrous oxide (N₂O) emissions from landfills and wastewater systems can be reduced through improved design and waste management. In energy and industrial sectors, address methane leaks from fossil fuel operations and manage N₂O and F-gases (SF₆, PFCs, and HFCs) in the chemical industry and in consumer goods like air conditioners.

Examples🔗

Methane leakage from energy systems:

Detection of leaks using drones and satellites; repair of leaks; and upgrade of valves and pumps to prevent leaks.
Methane recovery during fossil fuel extraction and processing, either for power generation or for flaring instead of venting.

Methane and nitrous oxide (N₂O) from waste:

Education and policies to reduce waste.
Capture of methane from landfills.
Careful control of oxygen levels in wastewater treatment systems to prevent methane and N₂O formation.

Nitrous oxide (N₂O) from industry:

Removal of N₂O during manufacturing processes by converting it to nitrogen and oxygen.

Fluorinated gases:

Recovery and recycling of refrigerant gases and use of alternative refrigerants such as CO₂, propane, and isobutane.

Big Messages🔗

Improving waste management practices and reducing leakage from energy systems can substantially decrease the amount of methane, nitrous oxide, and F-gases produced.
Methane, N₂O, and F-gases have a greater heat-trapping effect (per unit weight) in the atmosphere, and certain types can persist in the atmosphere for longer periods, compared to CO₂. Addressing these emissions is a powerful mitigation strategy.

Key Dynamics🔗

Diffusion dynamics. It takes time for best practices to be developed, improved, and implemented, and for policy to support their adoption.
Capital stock turnover delays. It also takes time for higher-emitting infrastructure (e.g., power plants, fuel processing facilities, and industrial plants) to be retired and replaced by new, lower-emitting capital or retrofitted to produce less emissions.
Scale and intensity. There are two ways to change emissions: decrease the overall scale of production, and decrease the emissions intensity of that production through adoption of improved practices. For an in-depth understanding of methane emissions, read the Methane Explainer.

Potential Co-Benefits of Reducing Waste and Leakage🔗

Reducing methane leakage from natural gas systems can save money.
Composting food waste instead of sending it to landfills yields nutrient-rich soil amendments.
Reducing N₂O emissions helps protect the ozone layer, since N₂O is currently the biggest source of ozone-depleting emissions.

Equity Considerations🔗

Adoption of practices to limit emissions in some industries requires technologies or methods that add costs to goods, potentially raising prices for consumers.
Alternative substances used to replace F-gases may have different safety considerations, such as flammability or toxicity, which need to be carefully evaluated and managed.

Slider Settings🔗

Moving the main Waste and Leakage slider changes the level of global adoption of best practices in all four areas: methane leakage from energy, methane and nitrous oxide from waste, nitrous oxide from industry, and F-gases.

	highly reduced	reduced	status quo	increased
Percent of potential reduction	100% to 70%	70% to 20%	20% to 0%	0% to -10%

Best practices for the energy and leakage area only reduce the sector’s methane emissions intensity (methane released per unit produced). One can change the overall scale of fossil fuel energy production via various energy sector sliders and see the results in the “Methane Intensity of Primary Energy” graph.

Best practices for methane and nitrous oxide from waste, reduce both the scale of waste production (particularly organic materials entering landfills and wastewater treatment) and also the emissions intensity (how much pollution per unit of waste).

For nitrous oxide from industry, the maximum potential represents a 95% reduction from the 1990 emissions value, consistent with the maximum potentials reported by Jörß et al. (2023). The slider sets how much of that maximum reduction is achieved over 30 years.

For fluorinated gases, the maximum potential represents a 95% reduction from the 1990 emissions value, consistent with the Kigali Amendment to the Montreal Protocol for F-gases. The slider sets how much of that maximum reduction is achieved over 30 years.

Note that a 100% reduction of the “Methane and other gases from waste and leakage” slider is not a 100% total emissions reduction, since some emissions are considered unavoidable.

Model Structure🔗

En-ROADS calculates the methane intensity of energy (measured in kilotons of methane per exajoule of energy produced). Emissions can be reduced through retrofits or replacement as newer lower-emitting technology becomes available. Emissions can also be reduced by changing practices (e.g., not flaring) and maintenance and monitoring (e.g., fixing leaks). Similar dynamics drive methane emissions from waste, nitrous oxide (N₂O) emissions, and F-gases.

About 10% of the methane from fossil fuels, and 100% of the methane from bioenergy generation, comes from incomplete combustion and is not affected by this slider. It can only be reduced by not burning the fuel.

Each greenhouse gas is modeled separately within En-ROADS, which enables the impact of each gas on global temperature to be handled without using global warming potential (GWP) and CO₂ equivalency conversions. Greenhouse gases other than CO₂ that are reflected in graphs with the units CO₂e use GWP100 to enable comparison and reporting of all greenhouse gases together, but only for documentation purposes.