Overcoming the Gigawatt factory challenge
The PV industry's next major cost-reduction driver is expected to be economies of scale in manufacturing. This is not a sure thing, however. Two key economic factors must change drastically for the industry to achieve this critical point: the cost of production and the power output of the PV modules.
Larger production volumes are already enabling the industry to lower its per-unit costs. Thus far, the rule of thumb has been that each doubling of capacity produces production-cost reductions of approximately 20%. To accelerate this trend and achieve the highest possible yield, however, it will be necessary to bring new, highly automated (for instance, less manual assembly and handling) manufacturing lines into production in a shorter timescale, for example in 6 months – versus 9 to 12 months at today's pace.
What is watt peak?
Watt peak (Wp) is the measuring unit for the standard performance (power rating, or wattage rating) of a photovoltaic cell – or a photovoltaic module – under standard test conditions. Module prices are typically indicated in €/Wp. 1000 watts peak = 1 kilowatt peak.
What are standard test conditions?
The test conditions that have been established stipulate that a light source radiates vertically with an intensity of 1000 W/m2, and that the temperature be 25ºC and the air mass 1.5
Source: Q.Cells
Furthermore, PV-generated electricity will need to become more cost competitive through improved conversion efficiency, module cost and total system cost. Total system cost is tied closely to easier and faster installation procedures, decreased installation material costs and less costly inverters. Today's market price to produce a PV module is between US$4.50 and US$5.50/W. That price will need to drop to less than US$2 for the industry to compete successfully against fossil fuels on a global basis without Government grants and subsidies.
To effectively leverage economies-of-scale advantages, today's traditional production facilities with outputs of 30 to 120 MWp must grow into 1 GW plants. Moreover, recent decisions by leading PV cell manufacturers to invest in major capacity increases by 2008 and 2009 signal that the industry is headed in the right direction. The leading producers have established a goal to surpass the 1 GW mark by 2010, but international competition to reach that milestone first will be fierce.
Close cooperation and collaboration between cell producers, equipment manufacturers and plant managers will be required to meet the GW challenge, since achieving that unprecedented level of production presents new technological and financial challenges for the industry and its suppliers.
Thin-film technology potential
Until now, the implementation of grid-connected systems, often sustained by subsidies, has driven growth. These advances have been slowed, however, by a shortage of silicon, which has forced the PV cell industry to compete with semiconductor manufacturers for silicon. The competition has also put upward pressure on PV prices. The good news is that worldwide silicon supplies should increase in 2008, thanks to several planned factory expansions. In addition, silicon supplies are likely to be further extended by recent advances in the production of thinner wafers, which use less silicon.
On the technology front, noteworthy improvements include reducing the cost of PV cells through new materials and processes that require little or no silicon. Moreover, newer technologies and topologies that benefit from these processes and materials have shown better conversion efficiencies and are likely to become more widely used.
Two main technologies are used to produce PV cells. The most prevalent silicon PV cell technology, which uses either c-Si or multicrystalline silicon (mc-Si), supplies about 90% of worldwide cell demand. The balance comes from thin-film technologies like amorphous Silicon (a-Si), Micromorph Tandem technology, Cadmium Telluride (CdTe) and Copper Indium Diselenide (CIS).
To help customers and consumers reach grid parity through its thin-film PV module technology, Oerlikon Solar has introduced an environmentally friendly, energy-conscious micromorph tandem technology that combines two different silicon materials – amorph and microcrystalline – in a top and bottom cell.
The amorphous top cell converts the visible part of the sun's spectrum, while the microcrystalline bottom cell absorbs the sun's power in infrared spectrum. This new micromorph tandem technology boosts the efficiency level by approximately 50% compared to traditional amorphous single cells. This process not only reduces energy production costs, it also has the potential for reaching conversion efficiencies of more than 10%. A further incentive to customers is that Oerlikon Solar uses materials that are non-toxic, low cost and readily available.
Thin-film cells present significant growth opportunities. Consultants Solarbuzz expect sales in 2010 to be at least 10 times higher than 2005 levels, as more manufacturers begin large-scale production. Worldwide, thin-film technologies are expected to account for 20% of the PV market by 2010.
