IT distributor Mustek has been inviting businesses and residential associations up on to the roof of its Midrand offices, in order to admire the view of its new solar installation. The 210kWp array has been put together by Green Habitat using panels supplied by the distributor, and is reckoned to be saving the company over R80 000 a month on its electricity bill already. The firm reckons that taking into account Eskom price rises, it can save 15% of its energy bill a year and will get its money back on the solar investment in around four years.
Of course, if you’re also a major distributor of solar panels, it helps to have an installation like this to convince your customers to buy from you – and the office roof is very much a demonstration of what’s possible.
As with its Mecer range of PCs, laptops and tablets, Mustek thinks it will be able to reduce costs by sourcing as much as possible locally. For example, the system developed in conjunction with Green Habitats uses as large metal grid attached to the roof only at the edges as the base for the panels, because drilling supports for each one individually would weaken the structure of the building and create an issue with waterproofing. The grids are manufactured in South Africa and the fastening system was designed by a local company.
Much of the electrical systems used to connect panels to inverters are also built locally, using fewer than normal imported parts. Right now, the panels are bought off-the-shelf from Taiwanese manufacturer Winaico, but Mustek plans to start assembling its own panels within the next year, using a mix of imported and locally sourced components.
According to Maurits Perold of Green Habitat, Mustek has already reduced its energy consumption from 318MW a month to 245MW since July 2008, encouraged by rising Eskom prices and instability of the local grid. One thing the current solar installation can’t do, however, is provide power when the grid goes down: the inverters used to match the solar output to that of the mains will feed back into the grid when there’s a power cut, running the risk of electrocuting engineers working at local substations. Until the entire mains grid is fitted with safety trips that prevent backwards flow, buildings like Mustek’s will have to continue to rely on generator back-ups.
For firms looking to invest, Perold says that his firm can help find sources of funding and rebates on kit. It’s partnered with the International Development Corporation, for example, for cut-price loans at fixed interest rates. IDC says that it has a pot of R300m to lend out new solar projects, thanks to backing from German and French development agencies. The Department of Trade and Industry will also offer grants of up to 50% the installation costs as part of a strategy to increase renewable use in South Africa and reduce reliance on the Eskom grid.
(Main image credit – Google Maps)