Solar PV systems represent a key and growing form of renewable energy with falling costs making them increasingly viable for a wide range of applications. Crystalline silicon (“c-Si”) is the most common PV technology utilised today; the first generation PV technology that comprises of both mono- and multi-crystalline technologies. More recent second generation “thin-film” PV technology includes silicon-based (amorphous and micromorph) and compound technologies (cadmium telluride and CIGS).

Key advantages of thin film CIGS

After extensive review of the available technology options in the context of local market conditions, BLS has selected thin-film CIGS technology as the basis for its proposed manufacturing facility taking account of the following key advantages of thin film CIGS:

  • High local content of over 75%;
  • A lesser temperature co-efficient that allows CIGS panels to produce more energy at high temperatures;
  • An ability to use a broader spectrum of light, this allowing CIGS panels to generate more electrical energy even on cloudy/overcast days;
  • Fewer production steps reducing manufacturing costs by up to 25% in comparison with other technologies;
  • A more environmentally friendly manufacturing process resulting in much lower toxicity than for Cadmium Telluride (“CdTe”) modules; and
  • Higher conversion efficiencies as demonstrated by recent independent studies in various parts of the world.
  • The thin-film CIGS module manufacturing facility to be based in the ELIDZ is intended to be constructed with 165 MW annual output. The size of the plant is defined in terms of effective production capacity (MW) or output.

Efficiency Comparison CIGS

Table 1: Efficiency comparison

figure1

Source: PWC, Supplier websites and “Progress in Photovoltaics” by Green et al

Efficiency comparison

Thin film technology efficiency is improving and becoming more competitive with crystalline silicon on an efficiency basis. In the short term, polycrystalline will continue to dominate as the market still views it as the more mature technology. Mono crystalline offers much higher efficiency; however this comes at a cost and is thus favoured where space is premium. Thin film has good future potential if the growth in production efficiency can be sustained to surpass polycrystalline.

Technology Evolution

The graphic depiction below illustrates the technology evolution

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Technology Evolution

Solar PV technology is differentiated by the type of photovoltaic material used, resulting in a range of physical properties and conversion efficiencies. The two common PV technologies that have been widely used for commercial and utility scale projects in South Africa are Crystalline Silicon (from suppliers like Yingli and Jinkco) and Thin-film (from suppliers like Solar Frontier, Manz and First Solar).