Handbook of Energy Storage for Transmission or ... - W2agz.com

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3. Applications
3.1. Applications Overview.
Due to its relative mechanical complexity and economies of scale, the VRB is most
suited for utility-scale power systems in the 100 kW – 100 MW size range in applications
having low power/energy ratios (long discharge durations). The principle T&D
applications with these characteristics include:
• DR/Peak Shaving
• Spinning Reserve
• Windfarm Stabilization & Dispatch
It is generally accepted that the viability of electricity storage is dependent upon cases in
which multiple operating modes – and multiple economic benefits – can be exploited.
For example, peak shaving economics is driven primarily by the benefit of local T&D
peaking capacity that the storage system provides. However, dispatch during peak times
also reduces the import power requirements from the generation sources, thereby
reducing generation costs. In this example, the economic benefits of the two applications
are combined.
While the VRB (and other storage technologies) can be used in a wide variety of
applications, it is not always possible to combine them. For example, energy storage
allocated for spinning reserve could not be “spent” for energy arbitrage since, in a
depleted state, energy would not available if called upon for reserve 2 .
Table 3 presents an overall summary of the applications requirements. The remainder of
this section covers the applications in additional detail.
2 On the other hand, energy dispatched by the system operator for reserve power may result in incidental
“arbitrage” benefits, depending upon the conditions of the performance contract and the market rules. This
benefit would be small since the timing of the dispatch would not necessarily occur during optimal
arbitrage conditions. It is worth noting that available energy capacity could be operationally “partitioned”
to separately serve spinning reserve and arbitrage functions.
Vanadium Redox Battery 21