California once again showed its leadership in integrating battery storage into the electricity grid last month, when Imperial Irrigation District (IID) commissioned one of the largest battery energy storage systems (BESS) in the North America.
Representatives from IID joined Coachella Energy Storage Partners (CESP), electric industry leaders and local and state officials, Oct. 26, to launch the 33-megawatt (MW), 20-megawatt-hour (MWh) system. IID installed the lithium-ion BESS to increase reliability while integrating renewable energy resources into the local grid. The storage system allows the utility to balance power, arrest frequency decay, provide spinning reserve, mitigate large fluctuations of energy, increase voltage stability and deliver “black start” power restoration capabilities for the nearby El Centro gas generation plant. A black start is the process of restoring an electric power station or a part of an electric grid to operation without relying on the external transmission network.
Integration poses challenges
The dedication ceremony was the culmination of more than three years of assessment and planning.
Like many utilities, IID is feeling the pressure of increasing amounts of renewables on its electric system. Those pressures are likely to grow as the state pushes toward its goal of a 50-percent renewable energy supply by 2030, especially since IID is located in such a resource-rich area. IID’s grid already carries 900 MW of clean energy—mostly geothermal and solar—with another 1,200 MW of new generation seeking to interconnect to its system.
“Specifically, the integration of solar generation was affecting our balancing authority, and our control performance standard began to suffer,” said Jesse Montaño, IID manager of planning and engineering.
Battery storage was a cost-effective solution to address ramp, regulation, capacity, ancillary services, system reliability and power quality. It is also environmentally friendly because smoothing the power supply and providing a spinning reserve are functions usually performed by expensive fossil fuel generation.
Putting pieces in place
After settling on the appropriate battery storage solution, IID issued a bond and drew on its capital spending budget to finance the $38 million project.
CESP won the district’s solicitation for 20 to 40 MW of grid-scale energy storage, beating out eight other vendors in the final round to serve as general contractor for the project. The company chose the energy project management company ZGlobal Inc. to oversee construction and General Electric to build the system.
GE supplied a comprehensive package which includes the lithium-ion battery with its inverters, plant controls, transformers and medium-voltage switchgear in a single enclosure. This is one of GE’s largest energy storage projects to date and one of its few lithium-ion storage projects. The company recently rebooted its lithium-ion battery business and also won a contract in April for an 8-MWh battery energy storage system for Con Edison Development in Central Valley, California.
Construction took about one year to complete, demonstrating that a storage battery can be sited and deployed relatively easily. However, every system is different and poses its own challenges to integration. “The BESS replaces some of our need for spinning reserves, but it was continually reacting to mitigate the slow ramping capabilities of IID’s generation fleet,” said Montaño. “We had to adjust reaction parameters on the BESS in order to economically and reliably balance the system.”
Testing followed so that when the BESS came online in October, it was ready to provide benefits to IID and its customers. On top of the operational benefits of increasing reliability and bringing more flexibility to the utility’s system, the BESS offers economic advantages, as well. It enables load shifting that reduces the need for expensive spinning reserves and is expected to result in significant cost savings to rate payers over the life of the project.
Every utility has a different power mix and different load, so battery storage must be evaluated on a case-by-case basis. But IID’s project illustrates many of the technology’s potential benefits and should give power providers elsewhere in the country much to think about.
Source: Public Power Daily, 10/31/16