How Springfield will use trash and sewage to produce renewable natural gas

Springfield’s garbage and sewage could soon produce renewable natural fuels that can be used to fill gas tanks, produce electricity and heat local homes. As landfills and sewage treatment plants capture biogas, city officials want to go a step further and turn it into a renewable alternative to fossil fuels.

Where does the gas come from?

Excess methane collected at the Springfield Noble Hill Sanitary Landfill in Willard is burned.

The organic material that produces the gas comes from animal excrement, human waste, food waste, garden and crop waste, sewage and municipal solid waste. This gas is collected to protect the environment. In its most basic form, gas is burned or flared.

To go a step further and produce useful biogas, organic material coming through the Noble Hill Sanitary Landfill and the Southwest Wastewater Treatment Plant in Springfield is subjected to an anaerobic process that removes contaminants and compresses the gas, allowing for greater energy consumption. Deputy Director of Environmental Services Ron Petering said the biogas is currently used to produce electricity for landfills and processing plants, offsetting the amount of electricity purchased from utilities.

The graphic shows how gas is treated and used at the Noble Hill landfill in Springfield.

How will this work?

The city now plans to further process this biogas, removing additional pollutants and conditioning the gas to increase the methane content to 90% or more, which would allow it to be reinjected into pipelines.

From there, renewable natural gas (RNG) can be transported, used locally, or sold to utilities for use in automotive fuel, electricity, or other industrial uses. Petering said CU is considered one such partner. Due to its renewable nature, the gas could also be sold under revolving production credits, which would be purchased by parties that might have to meet EPA standards requiring that transportation fuels include minimum amounts of renewable fuels.

The graphic shows how gas is treated and used at wastewater treatment plants in Springfield.

Sales of RNG would be market-driven and prices would fluctuate, but the city estimates it could bring in between $4 million and $19 million annually, according to an Environmental Services feasibility study completed in late 2022.

What’s the schedule?

Work on the project is scheduled to start this fall and last approximately 18 months. Petering said RNG production would be possible in fall 2025 or spring 2026. The project would include both the landfill and the Southwest Wastewater Treatment Plant.

Trucks unload trash at the Springfield Noble Hill Sanitary Landfill in Willard on Thursday, March 2, 2023.

How much does it cost?

The initial capital investment to construct the necessary facilities, including biogas treatment equipment, gas compression equipment and a pipeline connection point, will cost an estimated $31.6 million, with ongoing operating costs of $3 million per year.

Petering said most of the construction costs will likely have to be financed. However, the nature of the project provides unique financing opportunities, which motivated Springfield and others to pursue the project.

One possible source of financing is federal investment tax credits, which provide up to 30% tax credits to tax-exempt entities that invest in renewable energy projects and meet certain standard requirements. Petering said the state is currently awaiting information on the Environmental Protection Agency’s Climate Pollution Reduction grant. Springfield’s RNG project will be on the state funding list if Missouri receives the required funding. EPA is expected to announce a funding decision in July. If Missouri receives the full amount requested, the Springfield project could be funded up to 70%.

Petering said that if the project does not receive external financing and has to be fully funded, it would take about eight years to service the debt under the most conservative revenue projections.

What is the benefit?

Petering said that from an environmental perspective, the project benefits everyone. Once the system is up and running and producing renewable gas, the revenue will provide the city with more resources that can be reinvested in environmental services infrastructure and offset rising costs as regulations tighten and more resources need to be invested to meet requirements.