A Dynamic Programming Approach to Estimate the Capacity Value of Energy Storage

Abstract

We present a method to estimate the capacity value of storage. Our method uses a dynamic program to model the effect of power system outages on the operation and state of charge of storage in subsequent periods. We combine the optimized dispatch from the dynamic program with estimated system loss of load probabilities to compute a probability distribution for the state of charge of storage in each period. This probability distribution can be used as a forced outage rate for storage in standard reliability-based capacity value estimation methods. Our proposed method has the advantage over existing approximations that it explicitly captures the effect of system shortage events on the state of charge of storage in subsequent periods. We also use a numerical case study, based on five utility systems in the U.S., to demonstrate our technique and compare it to existing approximation methods.

Comparing the net cost of CSP-TES to PV deployed with battery storage

“…3 Dashes indicate configurations not tested. We do not evaluate plants with less than 6 hours of TES, due to reduced capacity credit, although this relationship needs more examination (Sioshansi et al 2014). …”

“…Although the capacity credit earned by long-duration storage is less established, we assume six hours of battery storage capacity is sufficient to earn full capacity credit (see Sioshansi et al 2014).…”

“…As a result, installation of PV alone cannot meet system peak demand. However, a decline in battery costs could make the technology a viable option for provision of firm capacity (Sioshansi et al 2014). Here, we attempt to determine if the total cost of CSP-TES, considering its benefits of dispatchable energy and the ability to provide firm capacity, surpasses the total cost of PV combined with firm capacity resources such as long-duration batteries or gas combustion turbines (CTs).…”

Energy Storage System Sizing Based on a Reliability Assessment of Power Systems Integrated with Wind Power

“…Capacity value is the metric typically used to quantify the contribution of generation on system reliability and for long-run resource adequacy planning [9]. Capacity value is often estimated using reliability-based methods [9].…”

“…Capacity value is often estimated using reliability-based methods [9]. In these studies, the chronological method and the probability method are used.…”