Seven-year payback time for Dube TradePort solar installation

The 650 kilowatt-peak (kWp) rooftop solar photovoltaic (PV) installation at the Dube TradePort, north of Durban, would take seven years to pay for itself, energy specialist Power Solutions MD Axel Scholle said in an interview this week.

“The R16.6-million installation goes a long way in closing the gap between historically cheaper electricity tariffs and the expensive electricity tariffs of the future, taking into account State electricity utility Eskom’s compound tariff increases,” he said.

Power Solutions was awarded the Dube TradePort project, which is said to be Africa’s largest rooftop PV installation.
Scholle believes that the PV industry in South Africa is set to play a more important role in power generation, with the country’s Integrated Resources Plan allocating substantial growth for PV in the coming years.

He estimated that there currently is about 12 MW of installed PV capacity in South Africa, of which only about 2 MW is connected to the national grid. This could increase to about 13.5 MW of PV capacity, as projects are coming on line in response to the government’s programme to procure 3 275 MW of renewable energy capacity before 2016.

“There should be more PV manufacturing taking place in South Africa, but with the low popularity of this form of energy generation at present, it is very risky. With government calling for proposals to increase the on-grid contribution of PV power plants in the future, local PV panel manufacturing would become viable business concerns,” he said.

It would make sense to invest in PV installations, as the technology has been in development over the past 50 years, resulting in the high-efficiency and long-life panels being manufactured today.

Scholle added that although it entailed an energy-intensive process to manufacture PV panels, the energy that one gets out of each panel is 10 to 15 times more than what is used to manufacture it. This helps to reduce the carbon footprint of PV panels.

The 1.7 m2 panels used at the Dube installation each have a generation capacity of 220 W and weigh about 20 kg.

“The longevity of these panels is significant. These panels carry a manufacturer’s guarantee of 25 years, with the possibility for it remaining in use for well over 30 years,” Scholle said.

However, the efficiency of PV panels vary according to weather patterns, with cloudy weather, impeding the sun’s penetration, resulting in reduced efficiency of between 40% and 90%, while heat could also account for a loss of up to 10% of PV panel efficiency. A crisp climate for PV is ideal.

Scholle said that Dube PV installation is connected and running in parallel to the municipal grid, to supplement its own-generated power in adverse weather conditions.

The first phase of the PV system was installed before the seventeenth Conference of the Parties got under way in Durban on November 28. “We will install 630 kWp over two phases, while the remaining 20 kWp is not yet allocated for construction.”

SolarWorld Africa supplied the Dube TradePort panels.


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