Use of Storage Systems – Supply Shifting

Use of Storage Systems – Supply Shifting 

Overview

Pivotal180 Introduction to battery storage course covers a range of topics related to battery storage including energy markets fundamentals, types of battery storage, the uses of storage capacity, battery terminology, the economics behind batteries, and the risks associated with the storage investments.

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Video

Video Transcript 

Supply shifting occurs when the battery is charged in periods of low demand and dispatched in periods of high demand. This helps smooth out the demand profile across a day. Supply shifting can occur at a transmission and distribution level or for bulk power management. Let’s start with transmission and distribution supply shifting.

– You have probably seen transmission lines before. There are the big towers you can see sprawling across the landscape in certain areas. Transmission is the transfer of bulk, typically high voltage electricity, over long distances. Distribution refers to the final stretch of energy transfer to residences and businesses. Typically at low voltage. When talking about transmission and distribution supply shifting, we are most commonly talking about shifting supply to align with demand within the course of a day. The need for the energy from batteries across an evening peak they last between a few minutes and a few hours depending on the requirements of the day. Batteries must also be a minimum size to be effective in smoothing the load profile. It could be that the minimum power capacity is half a megawatt for a microgrid or perhaps 20 megawatt power capacity for a larger grid. Whatever the case your AA battery won’t be sufficient Jeff.

– Let us assume a minimum power capacity of 0.5 megawatts. And that transmission and distribution supply shifting will require durations between minutes and hours. We can plot transmission and distribution onto our energy graph as shown. The graph shows that transmission and distribution supply shifting fits only within a range of energy requirements for the grid.

– When talking about bulk power management supply shifting we are normally referring to shift supply to align with demand over a number of days or weeks. Rather than charging and discharging a battery over one single day, these batteries will need to charge and discharge over a longer duration, perhaps up to a number of months. This may also be called seasonal balancing. Given the larger volumes of energy being discharged for seasonal balancing the battery power capacity required is often in excess of 50 megawatts.

– If we now add bulk power management to the graph we are starting to categorize where each use of battery sits in terms of the discharge speeds, duration, and capacity required. We will continue to add to this as we move into the next lesson on ancillary services.