Vanadium-powered batteries waiting to rescue Eskom
Mobile sources of electricity are a flexible and easily assembled solution to SA's load-shedding woes
As the government considers the restructuring of Eskom, energy minister Jeff Radebe has acknowledged the importance of including modular, flexible and lower-cost technologies such as battery storage in the planning process.
Eskom’s existing generation fleet is largely ageing, carbon-dependent and inflexible, and even the new power stations are unreliable. It is burdened with debt it cannot service. In restructuring the utility, the government needs to go further than merely splitting it into three parts of generation, transmission and distribution.
The minister told the recent SA Renewable Energy and Energy Storage Systems Conference in Cape Town that the large-scale uptake of battery energy storage would “accelerate the stable implementation of cost-effective renewable energy technologies, permit the decentralisation, modernisation and digitalisation of the electric grid and enable improved electrical power system flexibility, security and affordability”.
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Indeed, solar and wind power, combined with energy storage, should play a far larger role in the future energy mix than was envisaged in last year’s draft integrated resource plan (IRP) to 2050. In particular, batteries based on SA’s underutilised vanadium resource would have multiple benefits for the electricity system and SA as a whole.
Batteries add flexibility and reliability to generation, transmission and distribution. Vanadium redox flow batteries (VRFBs) are particularly well suited to large-scale uses. Using locally mined vanadium as the basis for local VRFB manufacture would serve both Eskom and other local customers as well as helping the government achieve its goal of developing more local manufacturing and skilled jobs based on the country’s competitive advantages. SA has the world’s largest resource of high-grade primary vanadium (that is, not mined as a by-product), nestled in the world-renowned Bushveld complex in the Limpopo and the North West provinces.
Batteries allow consumers to avoid the most expensive peak-time tariffs, usually on mornings and in the early evenings. That benefits the whole system because it reduces the demand at critical times, when everyone wants to use electricity and load-shedding becomes most necessary.
For Eskom, there are multiple benefits to using batteries as part of the generation mix. Batteries help to offset the inflexibility of baseload generation from coal and nuclear by supplementing supply through demand peaks and troughs. They also allow Eskom to capture energy from solar and wind when they are available and supply it when customers actually need it, and are considerably cheaper than using diesel-powered open-cycle gas turbines.
The costs of VRFBs are falling fast due to intense research in a number of countries, particularly China and the US. Although the vanadium price has soared in recent years, a unique advantage of the technology allows the vanadium to be leased to customers, rather than sold, or cheaply recycled, which helps lower its cost in the battery.
Batteries are particularly powerful when combined with variable generation sources such as renewable energy, especially solar, which is plentiful in Africa and increasingly the cheapest source of electricity. When paired with solar generation, VRFBs can already deliver energy cheaper than peaking plants and on a par with some of SA’s coal power plants.
Batteries can deliver electricity when it is needed rather than when wind and sun are available, which is rarely during peak demand times. Batteries can be located anywhere, relieving congestion in the transmission and distribution networks and obviating the need for investment in upgrading transmission lines.
Solar plants and batteries take months to build — much faster than nuclear, coal or gas-fired power plants, and they are modular. In developing economies where demand for power fluctuates, it is important to have electricity solutions that can be added quickly and incrementally.
The legal structure that SA will be putting in place for generation, transmission and distribution needs to make provision for battery technology, as it plays a role in all three areas. Sharing these benefits across all three is clearly desirable. This can keep SA from overbuilding in the power system and ensure lower electricity bills for consumers.
Although the draft IRP 2018 did not acknowledge batteries in the generation mix to 2050, Eskom is exploring their viability in place of concentrated solar power for flexible generation. It is currently testing various battery technologies, including a VRFB provided by Bushveld and the Industrial Development Corporation. The World Bank has recently announced a major battery energy storage programme that will mobilise $5bn and 17,500 megawatt hours of energy storage in developing countries, including SA. These developments suggest the role of batteries may also increase once the IRP is finalised.
In addition to supporting the government and Eskom, Bushveld Minerals, which owns the Vametco vanadium mine near Brits, is planning to install its own solar/VRFB minigrid for the mine. This will be a commercial proof of the concept, reduce its carbon footprint and provide protection against rising electricity tariffs and interruptions. The mine will supply the vanadium for the project, showcasing how SA minerals can be used to solve the country’s power challenges.
• Nikomarov is CEO of Bushveld Minerals subsidiary Bushveld Energy and chairs the SA Energy Storage Association.