City of Downey: Solar Energy Improvement Project

In 2023, CEG completed the development and implementation of a cost-effective renewable energy and resiliency program across city facilities for the City of Downey, CA. The program is being implemented over several phases to ensure that the City’s energy needs are met now and in the future. The initial phase included a Power Purchase Agreement (PPA) to provide on-site generated solar electricity for less than the cost of grid power. The project’s PPA structure allowed the team to leverage all available incentives (including the Federal Investment Tax Credit) to improve the financial returns for Downey. The team structured the PPA such that total annual utility cost avoidance is greater than $475k and net savings to the City exceeds $150k per year. 

CEG was responsible for the engineering, procurement, and construction of the 1.6 MegaWatt (MW) Solar PV, 2.2 MWh Battery Energy Storage Systems (BESS), and microgrid controllers across several critical city facilities in Downey, California. CEG started with a detailed analysis of utility data, load data, roof condition, and space availability to properly size rooftop and parking canopy arrays at each site to maximize the resiliency and financial returns of the program. CEG leveraged a hybrid racking design for the rooftop to reduce required roof penetrations and maintain existing roof warranties. CEG also designed the systems to benefit from Net-Energy Metering Aggregation to allow the City to offset electricity usage at numerous smaller City facilities while benefiting from the economies of scale or PV installations at the largest City facilities. 

To further increase the impact of the solar production, we installed four 250kW BESS that have a total capacity of 2.22 MWh. To further increase the cost-effectiveness for the City the BESS’ control system will automatically deploy stored energy to offset peak demand loads and energy rates for the City. The system includes real-time access to battery and PV status and different deployment and resilience strategies depending on the needs of the City. 

As part of a second phase, CEG is installing Level 2 electric vehicle charging stations to pair with the parking canopy solar arrays. Together, these measures reflect a 76% reduction in CO2 emissions across all City facilities.