What are the typical use cases for these large-scale BESS deployments?
BR: Typical use cases for utility-scale solar-plus-storage projects include fixed-shape hedge applications, where the battery fills gaps in the solar power curve and extends its shoulders to help meet offtake agreement obligations, and more traditional energy delivery power purchase agreements. Data centers are a good example of a fixed-shape hedge application. If you own and operate a portfolio of data centers, you know exactly what your load profile looks like on an hour-by-hour basis across a typical year. These operators are typically looking to purchase specific quantities of zero-emissions kilowatt-hours on an hourly basis for every day of the year. That energy could come from solar, from a battery, or from renewable energy credits off the merchant market. For sellers serving these customers, a BESS deployment acts as a buffer, smoothing solar energy delivery by reducing peaks and filling valleys and gaps to best fit the customer load profile. Developers also install batteries in purely merchant market applications, where energy storage operates as an alternative to natural gas peaker plants for late afternoon duck curve mitigation or ancillary voltage and frequency control support services.
How can project stakeholders mitigate risk in BESS applications?
BR: Availability and uptime are the top priorities for owners and operators of grid-scale batteries, especially if a revenue stream is contingent upon participation in a real-time market. If your equipment is unable to respond to those real-time market signals, you lose money. So, hardware and software reliability have a material impact on a project’s risk profile. Reliability indicators include metrics like mean time between failure (MTBF) and mean time to repair (MTTR). The challenge for project stakeholders is finding ways to confirm long-term reliability and durability based on potentially unknowable use cases. When a BESS asset participates in a real-time market, battery manufacturers must structure their warranties in a way that can accommodate an undefined use case. These flexible guarantees are based on a complex set of variables that includes the average state of charge, the number of throughput cycles, and the average temperature of the battery cells in a container. Because the manufacturer’s minimum capacity guarantee is contingent on all these factors, the project’s supervisory control and data acquisition (SCADA) system must be sophisticated enough to measure all these variables, potentially on a minute-by-minute basis. Without these data, you will not be able to comply with the manufacturer’s requirements when making a warranty claim.