By John Hope-Bailie, Technical Director Soltra Energy
There was burgeoning interest in rooftop solar photovoltaic (PV) power solutions for domestic, commercial and industrial applications in South Africa in 2018 as consumers from all sectors of the economy showed their increasing determination to reduce their reliance on Eskom.
Concern over power reliability and on-going load-shedding and looming electricity price hikes characterised the past year, persuading an increasing number of consumers to opt for solar power – nature’s free alternative – which continues to be seen as an attractive, cost-effective solution, particularly when compared to noisy diesel- or petrol-powered generator alternatives.
Decisions to select solar power as the ‘go-to’ option were often supported by developments in solar technology, including improved photo-voltaic (PV) energy density and wide spread availability of Lithium-ion battery technology.
These systems can be operated in three modes: linked to the electricity grid (grid-tied); as grid-tied unit with battery backup (in a hybrid standby mode for load shedding purposes); or as a stand-alone, off-grid unit providing maximum self-consumption. A period of load shedding, usually ranging from two to four hours, can fully deplete a battery pack. If repeated often enough, the batteries’ life can be reduced to around six months or less
South Africa has also seen a major step up in battery storage technology in 2018. The prevalence of now routine load shedding and power outages has exposed one of the Achilles heels of standby power devices. This is the shortened lifespan of batteries when subjected to full depletion on a regular basis. This includes specialised, sealed, deep cycle Valve regulated lead acid (VRLA) batteries.
This has seen a major move to investment in Lithium-ion technology which although still more costly then deep cycle VRLA batteries, has reduced in price considerably and come with a 10 year conditional warranty. When comparing life time costs the Lithium-ion battery compares very favourably, if not better than VRLA batteries. In addition, Lithium-ion has a much higher temperature threshold and occupy one third the footprint.
Efficient battery storage such as Lithium-ion technology has become one of the biggest game-changers in the South African energy landscape, which will continue to be characterised by a mismatch between demand and supply. It’s a technology whose time has finally arrived.