Case studies on BESS deployment in grid

Case Study 1: Hornsdale Power Reserve

The Hornsdale Power Reserve, located in South Australia, is the world’s largest lithium-ion BESS with a capacity of 100 MW/129 MWh. The installation began operation in December 2017 and provides two primary services: energy arbitrage and contingency spinning reserve.

For energy arbitrage, the BESS can bid 30 MW and 119 MWh of its capacity directly into the market. During unexpected outages, the remaining capacity is withheld to maintain grid frequency until other generators can be brought online. In 2017, when a large coal plant tripped offline, the BESS was able to inject several megawatts of power into the grid within milliseconds, preventing a cascading blackout.

Case Study 2: Green Mountain Power Project

The Green Mountain Power project, located in Vermont, is a 4 MW lithium-ion BESS paired with a 2 MW solar installation. The BESS provides backup power and micro-grid capabilities, as well as demand charge reductions.

The installation enables the utility to create a micro-grid that provides power to a critical facility even when the rest of the grid is down. The utility also uses the BESS to reduce two demand charges: an annual charge for the regional capacity market and a monthly charge for the use of transmission lines. Sandia National Laboratories estimated that reducing the annual demand charge for a single year saved the utility over $200,000.

In both of these cases, BESS deployment provides unique value to the grid system, offering faster and more accurate responses to frequency regulation, as well as the ability to provide multiple services simultaneously. However, proper compensation schemes and improved data and analysis capabilities are necessary to fully capture the economic viability of BESS deployment.