Using Wastewater Biogas Microgrids to Reduce Electricity Bills at Silicon Valley Clean Water

Presentation Description: Wastewater operators have to deal with high and rising electricity costs even as they face more stringent effluent discharge requirements. Wastewater biogas is a renewable energy resource that can be deployed with other on-site energy resources (batteries, solar PV) as a “biogas microgrid” that reduces electricity bills and earns revenues from offering demand response to the grid. In contrast to a typical biogas generation system that combusts biogas as it leaves the digester, a biogas microgrid controls the timing of a facility’s net electricity demand to maximize financial value. This control is achieved through accurate forecasting of baseload electricity demand coupled with real-time predictive control of diverse forms of energy storage (batteries, gas holders, food waste storage).
Here we showcase an AI-powered biogas microgrid advisor deployed at Silicon Valley Clean Water (SVCW) to recommend setpoints for a 1.26 MW cogenerator and 2 MWh / 1 MW Tesla Powerpack to their operations team. The tool runs on a SCADA data stream sending data every 5 minutes. Neural networks forecast facility demand and biogas production 1 to 24 hours into the future. These forecasts are then used by a machine learning algorithm to recommend optimal setpoints for battery charging/discharging and blending of natural gas into cogeneration engines. All processes are run on a secure on-site server; forecasts and optimal setpoints are viewable via a cloud-mediated user-interface. FLOWS Energy and Stanford are working to integrate the solution into its SCADA system so that the advisor can schedule recommended setpoints directly
Overall, we simulate bill savings and demand response revenues equivalent to roughly $300,000 per year, or 33% of SVCW’s baseline electricity costs. SVCW’s battery pays for itself in less than 8 years, earning more than 40% over its 15-year lifetime. These results highlight the potential for using electric time-of-use energy and demand charges to reduce electricity costs for wastewater facilities across California, both with biogas microgrids and other energy flexibility resources