What is a Standalone BESS

Standalone BESS solutions can be dynamically sized to suit any long-duration storage requirement, typically sized from 100kW/ 400kWh to 40MW/ 160MWh. Standalone solutions are usually made up of multiple containerised units and can stand in any convenient location within, or even outside of, a customer’s existing plant. Bushveld Energy has worked with most of the suppliers of containerised solutions and can identify the correct supplier for your specific application or location.

Standalone BESS’s are charged using grid energy, whenever it is available, although ideally during off-peak periods, when electricity prices are low. They are then discharged either when power is not available from the grid, such as power cuts or outages, or during peak charge periods to take advantage of the economics of load shifting.

Customers can start with relatively small systems, such as 1MW/ 4MWh, and once they see the benefits provided can gradually expand their facility. This expansion can ideally be suited to their budget or cashflow and can be justified on the basis of actual savings being observed on the ground. A 1MW/ 4MWh system would consist of 10 off 40’ containers, so as systems become larger (over 10MW/ 40MWh) consideration should be given to bespoke systems located in purpose built buildings. Existing standalone systems can then be moved to an alternative location (or locations).

Applicable Sectors

Commercial and Industrial

A BESS system for commercial and industrial applications is typically connected behind the meter and aimed at reducing a customer’s electricity bill through demand side management, load shifting and renewables integration. These systems are ideal for multiple use cases which are stacked and have numerous added benefits such as increased reliability and power quality, as well as load shift capability.

These systems are either comprised of multiple smaller modules or containerised systems built up to achieve specific power and energy requirements. One of the major advantages of VRFB systems is their flexibility in terms of decoupling the power and energy modules. These systems can be adapted to provide 4, 6, 8 or even more hours of storage, at the rated nominal power output.

Containerised modules can be built up to make a larger system, with a typical C&I unit being either 100kW/ 400kWh or 500kW/ 2MWh.

Isolated Sites Using Diesel Generators

Throughout developing countries, diesel generators are used to power communities and mines. Compared to other sources of electricity supply, diesel generators have low capital costs and generate electricity on demand, but have very high operating costs, especially when run at variable loads. Where clients do not have land on which to build a solar plant, a standalone BESS can be interfaced with existing diesel generators to reduce fuel consumption and run-time.

The diesel generators are operated at their optimum output, which improves both fuel consumption and maintenance requirements. Any excess energy produced is absorbed in the BESS and any shortfall of demand is provided from the BESS. This can be particularly beneficial when the operation is using a one or two shift system, as, with proper planning and sizing, the diesel generators can be shut down entirely for the night-time low demand period. This can allow routine maintenance to be carried out, or improved living conditions for staff.

The direct savings in diesel consumption and maintenance will more than pay for the BESS, over the 20 year lifetime of the battery. However, additional incidental benefits will accrue to the end user, as a result of the use of energy storage, such as voltage stabilisation, frequency regulation, power factor correction (leading to improved diesel power outputs) and many of other 40+ value streams identified.

Renewable Independent Power Producers

Traditional IPP’s can only produce energy when the wind blows or the sun shines and are dependent on the weather conditions at any given moment in time. As winds gust and solar intensity varies with cloud cover, the output from IPP’s is variable, by anything up to 75%. By adding energy storage to the wind or solar farm, this variability can be smoothed out. By adding long term storage the output can also be time-shifted, becoming a dispatchable output. This is far more valuable to a utility than non-dispatchable output that is a function of the available resources.

VRFB’s are particularly suited to IPP applications as they can achieve both the short duration load leveling and the long duration dispatchability requirements. In addition, VRFB’s are capable of providing power quality improvements and other ancillary services to the IPP and thereby to the grid operator.

Often IPP’s are constrained by the transmission capacity of outgoing transmission lines, so that part of their output must be spilled. This excess energy can be stored in BESS’s for later transmission when current output is lower and capacity exists on the line.

Sizes and applications of BESS’s vary on an individual basis. System design and location are critical to the successful deployment of large scale standalone energy storage systems. Contact Bushveld Energy for advice in this regard.


Standalone containerised energy storage systems would be considered small applications by utilities, but the advantage of such systems is that they can be added incrementally. In addition to load shifting benefits, Utilities also see reduced emergency peak generation (from OCGT) as a result of installing BESS’s into the grid. However, specific problems on heavily loaded transmission and distribution lines can also be alleviated.

Transmission upgrades involve forecasting future demand, which may or may not emerge. Lines have to be increased in incremental steps, with attendant large infrastructure investments. The use of standalone storage at sub-stations or at large loads on a particular line can relieve line congestion, either temporarily or permanently. Congestion generally only occurs during peak consumption periods. Injecting stored energy at these times and recharging the batteries during low consumption periods relieves the congestion on the line, thereby removing the need for transmission upgrades, reducing transmission losses, stabilising end user voltages and eliminating other power quality issues.

Storage can be installed incrementally, until the line is reaching full capacity at all times of the day, when upgrades will be needed, but against a known, and certain load profile. The temporary line deferral equipment can then be moved to another location.

The multiple value streams of such a BESS installation, and the incremental nature of such installations, often make a compelling business case for utilities to use long duration and long life VRFB’s.