The City of Roseville, California, has embarked on a groundbreaking initiative to decrease greenhouse gas emissions and minimize landfill waste through its innovative Energy Recovery Project. To bring Roseville’s energy recovery vision to reality, Brown and Caldwell designed a groundbreaking waste-to-energy plant that produces electricity, onsite heat, and renewable natural gas derived from digesting organics to fuel the City’s solid waste truck fleet.
While expanding the Pleasant Grove Wastewater Treatment Plant, the City wanted to explore the opportunity of beneficially using digester gas from their new digesters. We helped the City understand their options by evaluating digester gas use technology alternatives and recommending an economically favorable project to maximize the renewable gas quantity and capitalize on available digester capacity.
We evaluated multiple biogas utilization technologies, including microturbines, engine-generators, and biogas upgrading for vehicle fuel. We completed detailed design of a renewable biofuel production facility comprised of four microturbine cogeneration units, a high strength waste receiving facility, a digester gas conditioning system, and a digester gas upgrading system with onsite vehicle fueling. Design features provide substantial operational flexibility to allow the City to modulate when biogas is used for vehicle fuel versus cogeneration and adapt to local market conditions. Since late 2022, the City has been able to fuel 15 trucks a day and power 20 percent of the plant.
We also identified and delivered grants and incentives to help fund the project: an award from the California Energy Commission for Advanced Biofuels, loan forgiveness from the Clean Water State Revolving Fund (Green Project Reserve), and a Clean Air Grant from the local air district. In addition, we alerted the City to federal investment tax credit changes enacted in the Inflation Reduction Act and assisted the City in obtaining a $31.2M direct payment for the combined Expansion Project and Energy Recovery Project.
“We have come full circle with managing our integrated utility service to benefit our community. Through this project, we have the opportunity to generate environmentally beneficial by-products, mitigate the impacts of climate change, comply with regulatory obligations, and safeguard the interests of our ratepayers by stabilizing fuel costs for our solid waste fleet.”
Richard D. Plecker, Roseville’s Environmental Utilities Director