JSE-listed real estate investment trust Growthpoint Properties is piloting a 4.5 MW battery system at the Paarl Mall, in the Western Cape, for continuous, cost-efficient power supply, which will be partly charged by the mall’s new rooftop solar photovoltaic (PV) plant.

The R50-million system will extend the positive impacts of renewable, sun-powered energy around the clock, the company says.

Paarl Mall’s new rooftop solar plant will span 25 000 m2, have more than 5 000 PV panels with a direct current capacity of 2.5 MW and generate 3 601 MWh/y of energy.

Its sealed-container 4.5 MW battery bank system, comprising three 20-foot containers with lithium-ion batteries that have a 15-year lifespan, will be charged from both the mall’s solar power and the Eskom grid.

The system’s operation, production and yield will be monitored and managed off site, with the aim of optimal energy arbitrage, which is a technique where power is bought during off-peak hours, stored and used during peak hours. This enables peak-shaving that flattens the electrical load profile of the building. The system has also been designed to accommodate some of the mall’s demand during load-shedding.

“Proving the concept and technology would provide a big push in the right direction towards our carbon reduction targets. We are hoping to onboard more malls with this solution to future-proof our assets, protect them from load-shedding and optimise energy costs,” says Growthpoint retail asset management head Neil Schloss.

“With our clean, uninterrupted energy initiative at the Paarl Mall, we are striving to create a win-win for the mall, its community, the country and the planet. It is all about coming together and finding cooperative solutions for shared and sustainable long-term gains,” he adds.

The 60 000 m2 Paarl Mall is an ideal pilot site to prove how a sizeable battery system linked to a solar plant improves the environmental performance of large shopping centres and lowers the cost of energy, says Growthpoint sustainability and utilities head Grahame Cruickshanks.

The four-month installation will begin this month and the system is expected to be commissioned in early December. It should be fully operational by mid-December.

Growthpoint has installed 13.5 MW of solar power across its South Africa portfolio over more than a decade, but this is the first time it is integrating a large battery system.

Further, while the retail sector is best suited to this type of grid-tied integrated solar and battery system, Growthpoint sees potential value in using it at suitable properties across all its assets.

“Battery technology has come a long way in recent years. Previously prohibitively expensive, batteries have become increasingly affordable, especially considering rapidly rising electricity prices and our imperative to help prevent costly business disruptions for our clients caused by load-shedding,” says Cruickshanks.

Paarl Mall recently undertook an energy-efficient heating, ventilation and air conditioning upgrade to lower its electricity consumption. However, despite substantial energy savings, the centre’s electricity bill was set to increase by a hefty R5-million a year because the mall’s decreased load factor meant it qualified for a more expensive municipal electricity tariff.

In light of this, Growthpoint needed to tailor a new solution to provide green energy to the entire mall while ensuring a consistent power supply and optimising energy costs, Cruickshanks says.

Growthpoint’s retail and sustainability teams partnered with energy engineering firms Terra Firma Solutions and Anderson Consulting Engineers. The Drakenstein municipality adopted a proactive approach by providing the mall with the time needed to find the right energy-saving solution.

“We want to push the boundaries on the range of energy solutions available for our properties and our clients, expand our mix of energy sources and storage, and boost the supply of renewables to our assets as part of our proactive energy management,” says Cruickshanks.

Growthpoint will, in principle, be willing to sell excess solar energy produced at the Paarl Mall, but more clarity is needed on local wheeling arrangements before this option can be given serious consideration. For now, the company is focused on bringing affordable clean energy to the centre, ensuring continuity of operations and providing significant relief to the national power grid, he adds.