Overcoming the Labyrinth of Mixed Signals for Biogas Utilization in California

摘要

Current GHG, carbon neutral and renewable energy mandates in California would seem to create an ideal setting for application of at least, sustainable solutions, and optimistically, to enable conditions for a circular economy in the management of wastewater, diverted organics and their residuals by POTWs. However, on a practical basis, wastewater utilities are not able to select from the full range of co-digestion biogas utilization options applicable to their needs due to a labyrinth of mixed signals. For biogas derived from co-digestion of organics at wastewater plants in California the current challenges affecting its utilization have had a significant impact upon the option selected. All but one of 7 co-digestion projects is producing electricity; one project is converting biogas to CNG vehicle fuel for a local fill station onsite. The challenges include uncertainties associated with the value of vehicle fuel credits, onsite gas storage safety requirements, air permitting, air quality issues such as odor and negative effects of emissions on the public, and gas pipeline interconnection issues. Resolution of these challenges is needed to enable the success of California's program to divert organics from landfills. Further, developing guidance with a clear route for wastewater agencies to leverage their existing infrastructure to support implementation of organics diversion is critical to the program's success and meaningful GHG reductions.