Electricity + Control December 2020

ENERGY MANAGEMENT + THE INDUSTRIAL ENVIRONMENT

Improved storage technology key to renewables market Improving access to reliable and sustainable energy will be critical for economic and social development on the African continent.This is the view of Daniel Goldstuck, Head of Energy Storage Services at the SOLA Group who spoke at the solar and energy storage event in November, Solar Power Africa.

A ccording to the International Energy Agency, renewable energy will make up almost half of sub-Saharan Africa’s power generation growth by 2040. The uptake is largely a result of improved technologies, adjusted regulations promoting access to electricity and particularly renewable energy, and sub- stantial reductions in cost. Most national grids are designed in a way that requires a consistent and equal balance between electricity supply and demand to function properly. Goldstuck says that among the biggest challenges utilities face are when the electricity system cannot carry enough energy to meet the demands of consum- ers, or cannot distribute the excess energy across constrained networks. “The integration of bulk energy storage into an electricity grid can help utilities mitigate costs and reduce the chance of outag- es, particularly during periods of high demand or intermittency, which may become a concern with mass integration of solar and wind power,” he adds. Utilities are also making use of bulk energy storage to reduce costs. The provision of large-scale energy storage on site obvi- ates the need to build or expand large transmission lines from areas where electricity is generated, enabling power to be dis- patched consistently to meet demand. Goldstuck explains that, in addition to grid stability and cost reductions, energy storage provides an essential technology intervention in African countries where grid access might be limited or weak. “Energy storage can, for example, be used to serve additional power requirements where there are only nominal household grid services supplied via small energy devices – enabling economic development in previously underdeveloped areas. “Energy storage can enable the broader use of renewable energy, and energy services in general, in very remote areas,” he points out. In the energy storage market currently, lithium-ion batteries dominate, largely driven by the uptake of electric vehicles. Lithium-ion batteries are now emerging as a suitable technology for stationary energy storage with improved round trip efficiency, cycle life, decreased storage capacity degradation and black- start capability to restart grids that have experienced outages. Some of the new technologies that are expanding the energy storage market further include electrochemical energy storage systems, such as flow batteries and some non-lithium battery chemistries that boast improved long-duration capabilities. Flow

batteries, for example, circulate a liquid electrolyte through stacks of electrochemical cells and have long held the promise of 10-hour durations, tens of thousands of cycles and minimal degradation. Goldstuck says that at current costs, multiple forms of energy storage are now economically viable and offer improved duration capabilities that can accelerate solar and wind penetration and grid resilience, and serve to stabilise volatile energy prices if regulation and policy are improved. In South Africa, this has been recognised with Eskom calling for bids for the design and construction of a battery energy storage system (BESS) for the Skaapvlei substation at Vredendal, in the Western Cape. The aim is that the BESS will improve the export of energy from the Sere wind farm to the grid, while further BESS procurement under the same programme is intended to address voltage and capacity constraints, support the integration of renewable energy onto the grid, and reduce the need to expand some distribution substations and power lines. For the continent, the biggest challenge in this regard is that there has been a lack of policy commitment to fully integrate these new technologies. Goldstuck says this is imperative to ensure investment into large storage projects in Africa and smooth regulations around local storage assets within the distribution networks. Storage delivers benefits at all nodes of the network: as a transmission asset within a distribution substation yard to defer power line construction, or Reliable sustainable energy is critical to social and economic development in Africa.

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9 Electricity + Control DECEMBER 2020