While South Africa boasts an ideal climate for the generation of solar electricity through photo voltaic (PV) panels, solar power is not an automatic ‘quick fix’ for home owners hoping to cut their energy bills. This is because most households use the majority of their energy during early morning and evening peak times, which unfortunately do not correlate with the peak times for solar energy generation.

This is according to Alan Matthews, Head of Home Solutions at Energy Partners – a leading energy solution provider in South Africa, who says this can lead to consumers being disappointed with the savings from their installed systems. “The rapid growth in the home solar industry has led to many unscrupulous suppliers that promise consumers large savings, often ignoring the fact that a significant portion of the energy produced by the panels will not be utilised. These suppliers may try to sell their clients the cheapest possible solution, rather than advising them to invest in a more expensive but more effective solution”.

Luckily, the mismatch between production and consumption times can be addressed by including batteries and load management systems into home solar PV systems, says Matthews. “Rapid advances in energy storage technology mean that so called ‘hybrid’ systems that include batteries are becoming increasingly affordable. Hybrid systems work by allowing for excess solar energy generated during the day to be stored and utilised in the evening, or in the event of a power outage.”

He explains that the latest generation of lithium-based batteries that are now available in the country are vastly superior to traditional battery technologies. “These batteries can have a lifespan of more than 7 000 cycles, enabling them to provide a daily charge or discharge for over 10 years.

Another important element in a residential solar solution is a load management system, says Matthews. “These work by only switching on certain discretionary loads – like pool pumps, washing machines and geysers – when the PV system is active. That way, more consumption happens while the solar panels are generating.

He adds that in other developed countries storage has not been as necessary, because utility companies are willing to buy back extra energy from residential consumers. “Unfortunately in South Africa this is still not feasible in most areas as consumers get paid far less per unit fed back into the grid than is necessary to cover the cost of the system. In addition, home owners with prepaid or old mechanical meters will also be required to upgrade their standard meters to bi-directional meters at their own cost, in order to benefit from feed-in tariffs.”

“The best choice for consumers is therefore to utilise as much of the solar energy generated as possible, at least until the economics of these feed in tariffs change. This is not a difficult task – with a system that is designed to the correct size, combined with load management and some storage, it is possible to get ‘self-consumption’ levels up to 90%. This results in systems that will last for 20 years, but that pay themselves off in the first 6 or 7 years,” concludes Matthews.