Originally published in Revista Electricidad
The recent interconnection of Chile’s North and Central systems deserves great praise, but additional challenges persist. Recent transformations in the network due to the current energy transition and decarbonization goals have left regulators, network planners, operators, and market participants concerned about the best ways to continue the expansion of the National Electric System (SEN).
One approach in progress in several markets around the globe is to maximize existing network capacity with a non-traditional technology that is proven and ready to scale. Also known in many countries as “virtual transmission,” the addition of battery-based energy storage as a transmission asset at specific nodes reduces congestion, increases utilization of existing transmission lines, and lowers system operation costs.
Energy storage achieves these benefits by providing transmission capacity for reliability purposes normally provided by existing lines, enabling grid operators to maintain the n-1 contingency condition. Instead of holding back contingency capacity within existing lines, that capacity is provided by a grid-scale energy storage system replicating an additional circuit. Always synchronized with the grid, the batteries respond within hundreds of milliseconds in case of a contingency event. By making more capacity available on existing lines, the energy storage systems can reduce congestion without requiring building of new lines.
Energy storage has been solving important problems on electric grids around the world for over 12 years. Large-scale batteries have been added to transmission planning in different markets, with regulators finding the technology is proven and ready to scale. Chile was a global market pioneer when it installed grid-scale batteries in 2009 on the generation side and is now poised to pioneer a new application for energy storage and reap the benefits of storage as part of the transmission system.
Two recently submitted proposals to Chile’s National Transmission Expansion Plan demonstrate – using the same type of modeling run by CNE to evaluate new transmission lines – that adding a total of 500 MW of energy storage at the Punta Sierra–Nogales and Temuco-Cautin segments would generate a net present value in economies to the SEN of US$400 million on average (and possibly as much as US$600 million) by lowering generation dispatch costs. The increased capacity on those corridors allows transmission of more low-cost energy to the load centers. The savings would be generated by more efficient dispatch of the system resulting from the increased flexibility energy storage brings to the transmission grid.
This solution offers a wide array of advantages over traditional infrastructure, with response times in the hundreds of milliseconds range and a more modular, scalable form factor that fits the needs of a flexible grid. Energy storage implementation is far less disruptive socially and environmentally and can be deployed in just one to two years at the 100+ megawatt scale, compared to other upgrade options that typically take several years to implement.
Deploying energy storage as an asset inherent to the transmission grid gives Chile an opportunity to once again lead the world by incorporating an innovative, efficient, and technically versatile technology that will help guarantee open access to reliable, clean, and cost-effective power for Chilean citizens.