Energy storage is touted as a breakthrough technology crucial to changing Africa’s energy mix. To test this statement, ESI Africa explores what it could realistically do for South Africa’s national grid.
South African Energy Storage Association (SAESA) board member Paul Vermeulen is a big proponent of unbundling South Africa’s state-owned power utility, Eskom, into transmission, generation and distribution companies because he is itching to introduce energy storage into the local grid.
Vermeulen, who is also the chief engineer for renewable energy at City Power in Johannesburg, sees the unbundling process as a chance to uncouple the idea of the national grid as only a manifestation of Eskom and introduce the idea of an electricity grid as a community of energy producers and users.
Correcting the electricity tariff structure, balancing the grid even with a greater load of renewable energy, saving jobs at coal-fired power plants, maintaining municipal transmission lines – for the chief engineer, all of these problems are solvable if energy storage systems were incorporated into South Africa’s national grid.
Energy storage behind the meter
Speaking with ESI Africa, Vermeulen’s estimation is that energy storage as a solution is preferably behind the PV rooftop owner’s meter. While Vermeulen can lay out the facts and figures for how to effectively use utility-scale batteries on either the country’s high or medium voltage transmission lines, he believes energy storage on-site behind either the Eskom or municipal meter is an even better proposition.
He likens the idea to how South Africa already effectively uses geyser control as an energy efficiency measure. He points out that people don’t like the geyser control systems because it makes them feel as if they are being told what to do. The solution is in the introduction of a time-of-use tariff system and relays handed out to households. In doing this, Vermeulen advocates that people would change their behaviour because it can save costs and they would feel empowered to “be helpful to the power system”.
It doesn’t matter who controls the energy storage; it matters that it is used at the right time.
Vermeulen says there is an important lesson to be learned from the experience of controlling 100,000 geysers from a central point: “It doesn’t matter who controls the energy storage; it matters that it is used at the right time. Think smart grid, ripple control, tariff signals, and one million households, each with a kilowatt of storage, which is equivalent to a 100-megawatt battery on the transmission line.”
It’s a load management tool, not a generation solution
One important fact to remember, he adds, is that energy storage is not a primary energy generator. “It is simply a way to allow you to take energy and use it at a different time. A primary energy generating system only generates, whereas an energy storage system can absorb and release energy. In essence, it becomes a powerful grid management tool that can reduce peaks and fill the valleys in the load profile.”
Remember, energy storage is simply a way to allow you to take energy and use it at a different time.
Multiple studies around the world prove how energy stored on a grid can be released back into the system when needed, to either balance the load on a micro-scale or address peak energy demand issues.
Vermeulen stresses the need for people to stop talking about energy storage only in relation to renewable energy and the notion of going off the grid: “It can also help the ailing coal industry. Those new coal power stations must still generate a certain amount of energy to pay for themselves. If you have energy storage, there’s the schedulable load when you need it. The coal-fired stations must ramp down at night as Eskom curtails power generation in the early hours of the morning because the load goes too low. This is where storage becomes the load for coal, allowing the power generated to be used later in peak, without the need to also switch off renewables because they cannot switch off the coal generation.”
Policy direction, sorely missing
The SAESA board member points out that uncertainty around where and how energy storage fits into the South African energy landscape hampers any sort of bulk take-up of the technology, never mind innovation or adaptation to local circumstances: “The Electricity Act talks transmission, distribution and generation but nothing about the activity of energy storage, which is a complementary, but distinctly different activity to energy generation.”
The energy and power industry is continuously in motion: “At one stage, the activity of gas storage had to be added to the Gas Act, because storage of that form of energy has to be regulated in a different way to its transmission and distribution. The same is needed for electrical energy storage and while it’s probably only three pages that have to be added to the Electricity Act, it’s a lengthy process to get there.”
Storage has a future: it’s definitely the Swiss Army knife of the future electricity system.
A closing thought from Vermeulen leaves no doubt that storage has a future in the South African electricity supply industry landscape: “It’s definitely the Swiss Army knife of the future electricity system. It is part of the energy transition that you cannot do without. We just need the Department of Mineral Resources and Energy and the Regulator to come to grips with the idea that storage is good for the energy system as a whole, perhaps even more so outside of Eskom or the municipalities.” ESI