Reliable, cost-effective, 24/7 energy supply is an essential resource for successful mining operations, whether grid-connected or off-grid. The reliability of utility-sourced electricity can be a challenge for mines in Africa, while off-grid diesel generation and related fuel-supply costs and logistics may also be problematic.  In addition, the environmental impact of carbon dioxide emissions and escalating carbon taxes are also a consideration in the mining industry.

Solar energy is increasingly being used to substitute and supplement energy from both grid and off-grid sources; however, solar energy is not available around-the-clock, and is therefore seen as an inadequate source of energy, without the availability of long-duration energy storage.

Africa Energy Storage Solutions (AESS) focusses on clean energy storage solutions in Southern and East Africa. It believes that clean energy requires clean batteries and to this end, has been instrumental in the selection of the ESS Iron Flow battery as the storage technology of choice by a Southern Africa energy company working in the Southern African Development Community region, as well as in the first concept design of a 10 MW/40 MWh battery for delivering 24/7 solar power at various locations.

AESS is a representative of ESS, manufacturer of the Iron Flow battery and an established flow battery manufacturing company based in the US. The company also works with established engineering, procurement and construction organisations with a track record of delivering large renewable energy projects at national and international levels.

The two product configurations using the Iron Flow Redox electrolyte and power modules are:

• Energy Warehouse: a containerised turn-key solution, providing 33 kW, 50 kW or 100 kW ratings and 400 kWh storage capacity.  These may be stacked to several MW/MWh capacity. 
• Energy Centre: a  so-called ‘battery-in-a-building’ concept for multiple MW/MWh applications, using the same technology as the Energy Warehouse, but configured in multiple skid configurations according to specific requirements up to 1 GW.  The concept allows for the independent specification of power output (MW) and energy capacity (MWh), using flow battery technology to determine the energy capacity by the size of the electrolyte tank.

AESS states the additional features and benefits of the ESS Iron Flow battery as follows:

• Unlimited cycling: Lithium-ion batteries are usually guaranteed for only one cycle per day, however the Iron Flow battery can be fully cycled continuously without limitation and it has undergone extensive DOE ARPA-E testing.
• Zero degradation: Iron Flow batteries do not degrade with use and do not require augmentation, even when cycled continuously.
• Wide range of operating temperatures: The batteries can run without the need for air conditioning or supplemental heating, in ambient temperatures from -5 °C to 50 °C.
• Low cost of service: Iron Flow batteries are said to have the lowest overall cost of service for long-duration or multi-cycling requirements, especially in workhorse, heavy-use applications.
• Long-life asset: The ESS containerised storage system has a design life of 25 years.  Advanced cycle testing was conducted for the US Department of Energy, simulating over four decades of use, with no degradation in performance.  ESS states that it has had no reports of  performance degradation at any level and it has had no product failures since introducing its first commercial unit in 2015.
• No hazardous materials: Iron Flow batteries use no hazardous materials, which means that no hazardous material (hazmat) training, hazmat equipment, or hazardous chemicals disposal plan is required and routine maintenance can be localised.

Export–import credit finance instruments are available from US Ex-Im Bank  for up to 85% of the project cost qualifying customers incur in the purchase of the energy storage platforms. In addition, performance and business continuity coverage is backed by Munich Re insurance.