Grid storage to decrease electricity infrastructure cost

21st October 2016

Information and communication technology company Xon notes that grid storage solutions can help to overcome the challenges associated with the cost of building and maintaining infrastructure for total installed electricity.

The company notes that the total installed electricity generating capacity in 48 sub-Saharan Africa countries is roughly the equivalent of Spain’s, based on statistics from the World Bank. Further, as much as a quarter of that meagre supply is offline at any given time, owing to poor maintenance and ageing infrastructure.

“Regardless, one in five sub-Saharan Africans simply do not have access to electricity and fewer than 40% of African countries will achieve universal access to electricity by 2050,” notes Xon.

The company maintains that grid storage solutions can help to overcome infrastructure maintenance challenges and that this insight emerged at information technology solutions provider NEC Energy Solutions and Xon’s XON and NEC Summit, held in Limpopo, in August, which was also attended by Xon alternative energy MD Magnus Coetzee.

Grid infrastructure must be built to handle peak loads. That means overhead and underground cables must be thick enough to withstand low ampere but exceptional voltages to distribute electricity from the generating source to the point of use. Over the distance between Johannesburg and Cape Town, for example, losses to resistance can be as high as 30%.

“Nonetheless, the building of grid infrastructure must consider the cost of a two-, three- or four-inch copper core, with the requisite infrastructure strong enough to withstand nature and other forces across the entire length of the country. Maintaining that infrastructure is also a full-time job and the bigger it is to handle peak loads – representing just a fraction of the time the infrastructure stands – the more expensive it is to maintain,” notes Coetzee.

He explains that, if infrastructure could be built at a quarter of the size, build and maintenance costs could be cut over many decades.

Grid storage consists of banks of specifically suited lithium-ion batteries built into containers with sophisticated management systems. The alternating-current-coupled batteries are charged by the grid energy source during off-peak times and discharged to feed grid-connected households and businesses during peak load periods.

This is the same theory that is applied to pumped hydro storage. A recent example is the Ingula pumped-storage scheme being executed by State-owned power utility Eskom in South Africa to handle peak demand. Coetzee explains that, if one is to look at the power, useful capacity and current published cost, a grid storage solution from NEC would be at par in unit cost (dollars per kilowatt hour) with the added advantages of being easily scalable, locally deployable where the demand power is needed, not having the environmental impact that pumped hydro does and being operable within six to nine months from the time the contract agreement is concluded.

“This one change distributes electricity supply to the regional level, which results in a far more resilient grid infrastructure, as well as cutting costs to build and maintain,” says Coetzee. He adds that it could prove the significant differentiator in bringing energy supply to a greater number of African households.

Xon points out that these solutions have already been proven elsewhere in the world. In South America, for example, these containerised units are supplying enormous quantities of energy to the grid for different applications; the same model is used in the centre of London. In fact, 150 MW of power is already being supplied globally using this model.

“There’s no reason why African utilities cannot use the same technology to drive widespread economic growth as emerging markets, and specifically Africa, increasingly represent the force behind global economic progress,” concludes Coetzee.