Owner/Client:      City of Palo Alto

The City of Palo Alto was considering six different options for handling of the city’s source-separated organic waste, including food waste, yard waste, and biosolids from the regional water quality control plant. Options included dry anaerobic digestion, wet anaerobic digestion, various methods of composting, and incineration. Ascent evaluated the net change in GHGs associated with each option, considering multiple uses of recovered methane, including the generation of electricity for distribution by the City-owned electric utility, production of compressed natural gas for use in the City’s vehicle fleet, or production of pipeline-quality natural gas for use by the City-owned natural gas utility. Ascent’s GHG specialists worked closely with City staff and engineers to formulate a Request for Information to solicit key emissions-related information from providers of dry anaerobic technologies and evaluate responses from seven different respondents. Ascent developed a GHG model to perform a lifecycle analysis of the various waste handling options and compare their respective GHGs. This analysis was performed in conjunction with an economic feasibility analysis by the project’s engineer. Ultimately, the City used these studies to determine the cost per metric ton of GHG reductions on a net-present value basis.