By Dwibin Thomas, Cluster Automation Leader at Schneider Electric

Utility-scale battery storage is growing in leaps and bounds, with the US Energy Information Administration (EIA) estimating it will reach 30.0 gigawatts (GW) by 2025. This remarkable growth in battery storage capacity is outpacing even the early growth of the US’s utility-scale solar capacity.

The above is a clear indication that utility-scale battery storage is becoming the storage method of choice for developed countries such as the US. And rightly so, battery storage adds stability to variable energy sources such as wind and solar.

Renewable energy such as wind and solar are intermittent and can only provide electricity in optimal circumstances. Batteries overcome this problem by storing any additional energy produced by renewables, providing a stable base load when energy resources such as the grid, solar or wind aren’t available.

In South Africa, utility-scale batteries offer a stable storage solution particularly with more IPPs entering the market and providing renewable energy to alleviate strain on the traditional grid.

Here, it is vitally important that storage such as lithium-ion batteries form part of the energy provision mix from the get-go. As mentioned, renewables are intermittent and if it is backed up by battery storage it will allow IPPs to provide stable supply.

Battery storage mitigates both short-term and intra-day imbalances in power generation and in essence, stabilises the grid.

Looking at the practical application of utility-scale storage, it works on a similar principle as a domestic system where a renewable energy source charges the batteries and the energy is stored for use at night and/or when the grid is offline, or supply is unstable.

Utility-scale battery storage like any residential system requires a sophisticated energy management system (EMS) to provide insight into daily usage, provision, supply and so forth.

It therefore consists of hardware and software components. The hardware includes battery modules, battery racks, protection devices and inverters that convert the direct current (DC) of the battery into the alternating current (AC) of the coupled power grid.

The key software components are the Energy Management System (EMS), the Battery Management System (BMS) and a Supervisory Control and Data Acquisition System (SCADA).

The EMS acts as a higher-level operating system that integrates with external systems and manages the response to changes in demand and supply. The function of the BMS is to monitor the performance data of the battery modules and to regulate their charging and discharging. The SCADA controls and monitors all the processes of the battery system in real-time while collecting data on the system’s performance, such as voltage, current, and temperature, and provides alerts if there are any issues.

Lastly, and this an important benefit, battery storage can provide power to the grid in a matter of seconds, allowing for a seamless switchover between distributed energy resources (DER) and importantly providing stable supply to users.

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