San Diego , California, USA

Enersmart Energy Storage Portfolio in San Diego, California

Status: Under construction


According to the U.S. Energy Information Administration (EIA), in 2019, a total of 40.87 million metric tons of carbon dioxide (CO2) were emitted by the production processes of conventional power plants in California. The state government has established a series of policies and regulations aimed at reducing these emissions. One of the most important is the Renewables Portfolio Standard (RPS) Program, which through Senate Bill 1078 in 2002 mandated an initial requirement that 20% of electricity retail sales be generated by renewable resources by 2017. In 2018, Senate Bill 100 was signed into law, increasing the RPS to 60% by 2030 and requiring that all the electricity in the state come from carbon-free resources by 2045.

In line with those policies, power generation from renewable sources has increased in the state of California. In 2019, solar parks and wind farms generated more than 22% of the electricity consumed in California. Nevertheless, the curtailment of solar-powered electricity generation has increased in the California Independent System Operator (CAISO) region. In 2020, CAISO curtailed 1.5 million megawatt-hours (MWh) of utility-scale solar or 5% of its utility-scale solar production. To reduce the curtailment of renewable energy generation, additional energy storage systems need to be installed, which will allow CAISO to regulate and maximize the efficient use of electricity from these intermittent renewable energy sources.


The project consists of the design, construction, and operation of a portfolio of 55 energy storage facilities with a combined capacity of 165 megawatts in alternating current (MWAC). Each system will have 3 MWAC of power capacity. Electricity from the grid will be stored and delivered through specific transmission (Gen-Tie) lines to be built by San Diego Gas & Electric (SDG&E).

The portfolio will be constructed on nine project sites in San Diego County, CA. Each 3-MWAC system will be comprised of three energy storage containers, three inverters, one transformer, one switch box and one transmission line. More than one system may be housed in the same facility, but each one will be self-contained and operate independently from the other system(s). The number of systems and the expected energy storage capacity to be developed at each site is:

  • Chula Vista – 2 systems (6 MWAC)
  • Murray – 7 systems (21 MWAC)
  • Mesa Heights – 1 system (3 MWAC)
  • Imperial Beach – 2 systems (6 MWAC)
  • Alpine – 2 systems (6 MWAC)
  • Spring Valley – 12 systems (36 MWAC)
  • Chicarita – 10 systems (30 MWAC)
  • Border (Otay Mesa) – 6 systems (18 MWAC)
  • Creelman - 13 systems (39 MWAC)


The project is expected to benefit San Diego County by improving grid reliability, increasing energy efficiency and maximizing renewable energy use, while reducing the use of ramp-up/ramp-down fossil-fuel power generating plants. The 165-MWAC energy storage portfolio will be capable of storing up to 330 MWh of electricity, the equivalent of serving 120,000 customers for two hours. Annually, the project is expected to store and deliver over 100,000 MWh of energy, which will displace the emission of an estimated 35,480 metric tons/year of CO2. The project will also help integrate electricity generated by intermittent renewable energy sources, such as solar and wind, thereby allowing the CAISO region to continue increasing the penetration of renewables in its system and eventually reach its goal of a carbon-free electric grid by 2045. It will also support a more reliable power grid, by minimizing power disruptions and reducing energy losses resulting from mismatches in supply and demand.

Project Financing

Total Project Cost Reserved
NADBank Funding US 70.00M - NADBank Loan