In search of storage
Elon Musk got in first with his Powerwall, but the University of the Western Cape (UWC) is not far behind the SA-born whizz kid in developing a long-life home battery with plenty of storage capacity to beat loadshedding.
UWC, says Prof Ben Bladergroen, director of its Energy Storage Innovation laboratory, is “close to commercialising” a highly durable lithium ion (li-ion) battery providing two-hour back-up electricity for most household lights, small appliances and electronic devices.
Li-ion batteries, commonly used in such devices as laptops and cellphones, are not manufactured in SA. UWC’s Li-ion pilot plant is the largest in Africa and the only facility of its kind to manufacture Li-ion battery cells on the continent.
With four times the storage capacity of the widely used but less durable lead acid battery, which currently provides the only locally available means of small-scale storage, the UWC product can store 2,6 kW and includes a battery management system to check whether it is performing optimally. The battery will last about seven times longer than a lead acid battery, says Bladergroen.
UWC’s battery can be used to store electricity from the national grid for use during load-shedding or from solar panels which would need to be linked to an inverter to convert direct current from the panels into the alternate current required to run lights, appliances and devices. Larger-scale storage for commercial and industrial use could be achieved by operating a number of the batteries in parallel.
Bladergroen estimates that with production economies of scale, the UWC battery could sell for around R15 000. Musk’s Powerwall comes with 7 kW and 10 kW storage and is priced between US$3 000 (about R39 000) and $3 500 (R45 500). “It is reasonable to assume that the Powerwall will cost at least 50% more by the time it reaches the SA consumer,” says Bladergroen. If this is the case, the 10 kW Powerwall would cost about R68 250. Four UWC batteries providing 10 kW would cost in the region of R60 000 with the advantage of local customer support.
UWC’s recently launched Energy Storage Innovation Lab (ESIL) is the culmination of