Mobile communications company Vodacom  is currently installing a solar electric array of nearly 2 000 panels on the roof of its Century City office building, just outside of Cape Town. The array is believed to be the largest on a single building in Africa and will offset approximately 25% of the building’s electrical energy use throughout the year.Vodacom’s Executive Head of Corporate Citizenship, Suraya Hamdulay, explains that “over the last two to three years, we have gained momentum in positioning ourselves as environmentally responsible. We have established carbon reduction targets of 5% per annum over the next three years, and we are driving energy efficiency across all of our facilities.”

Overall sustainability strategy is driven by their national facilities management, but the company has a close working relationship with WSP Group.

The solar electric array consists of a total of 1966 fixed monocrystaline solar panels over 3 600 m2 of roof space. The roof has both sloped and flat areas and WSP Principal Associate Evan Pedlar says that for both roof types, there were construction challenges unique to a retrofit project.

Because the building is primarily used as offices occupied Monday to Friday while the sun is shining, the energy being generated is fed directly into the building where it is used immediately. “We don’t have any battery storage. It isn’t required for this type of building. You only really need batteries when you are trying to store energy for use outside of daylight hours,” explains Pedlar.

The question then arises of what happens to excess energy at times when it is not all being used by the building. De Jongh states that “on weekends when the system is producing more energy than is being used in the building, we will have to switch off some of the inverters. Unfortunately at this stage we are not allowed to feed back into the grid.”

“We have engaged with both the City of Cape Town as well as the chamber of commerce, because we know that business growth in the country is being hampered by the shortage of electricity capacity,” notes De Jongh. The array is, however, the first solar electric project to be registered with Eskom’s new small-scale renewable energy rebate programme, whereby projects are paid for the amount of grid electricity use avoided.

The Century City building solar array will not only decrease energy consumption and carbon emissions, but also serve as a learning opportunity for the company. Hamdulay notes that for several years Vodacom had been exploring how to integrate solar into a retrofit of their buildings. “We had the perfect opportunity to make use of an existing roof infrastructure that is well placed to maximize the solar energy captured. The lessons we learn here, we can then roll out on the rest of our campuses.”

 

* The full article appears in the October – November 2012 issue. Images: Jason Buch (www.jasonbuchphotography.com)