Photovoltaics: State of the Technology, 2012
By WOLFGANG PALZ, Ph.D.
The following module manufacturers led global markets in 2010:
- Suntech Power (China) 1.57 GW (Si)
- JA Solar (China) 1.46 GW (Si)
- First Solar (USA) 1.41 GW (CdTe)
- Q-Cells (Germany) 1.01GW (Si)
- Motech (Taiwan) 0.85 GW (Si)
- Gintech (Taiwan) 0.72 GW (Si)
- Sharp (Japan) (Si, a-Si, mc-Si)
- Kyocera (Japan) (Si)
The ranking is volatile. Sharp was the global leader for years. Q-Cells assumed the lead, until it experienced a financial crisis in 2008. First Solar took the helm the following year.
For 2010, Paula Mints of Navigant Consulting divides market share by technology this way:
- Monocrystalline silicon – roughly 43 percent
- Multicrystalline silicon – roughly 43 percent
- CdTe – 9 percent
- CIS/CIGS – 2 percent
- Amorphous silicon/multicrystalline silicon – 2 percent
Copper indium selenide (CIS) appears to be the up-and-coming segment. The latest example was the announcement in April that Solar Frontier, a company of the Shell Oil Group in Japan, opened a new factory for CIS modules in Japan. In July they reached their target manufacturing capacity of 1 gigawatt (GW), including 900 megawatts at the new plant.
Gallium arsenide (GaAs) cells have the highest efficiencies, achieving up to 43 percent recently. High cost limits their market to space satellites and concentrating photovoltaic (PV) systems.
While there’ve been only incremental improvements in crystalline silicon conversion efficiency for 40 years, they still offer better specific performance than thin-film cells, at 18 percent and higher for modules now widely available. SunPower leads with up to 25 percent efficiency for cells. The performance advantage is somewhat offset by the higher complexity of the silicon technology and hence a somewhat higher production cost.
The typical thin-film cell has roughly 1 percent the thickness of a comparable silicon cell, implying economies of material and production. Today’s market leader in thin film is cadmium telluride (CdTe), with conversion efficiencies as high as 12 percent. A thin additional intermediate layer of cadmium sulfide (CdS) contributes to this efficiency. The simpler thin-film technology leads to attractive manufacturing costs: First Solar has achieved half-a-euro per watt. But cadmium is a poisonous heavy metal. This raises a problem in Japan, which has a history of cadmium pollution.
No wonder then that Japan has turned its attention to CIS and amorphous silicon. The Japanese firm Solar Frontier mentioned has claimed a record CIS efficiency over 15 percent. The National Renewable Energy Laboratory (NREL) recently measured 15.5 percent on a 30-by-30 centimeter (12-by-12 inch) CIS cell from Avancis. The problem is a looming scarcity of indium, which may limit mass production.
Finally, amorphous silicon and multicrystalline silicon show promise. A new record, 12 percent, has been reported by NREL, on a cell measuring 400 square centimeters. This marks tremendous progress since the days of stability problems linked to the Stabler-Wronski effect in hydrogenated amorphous silicon. The solution, developed in Switzerland, was a combination with multicrystalline silicon layers.
Many PV manufacturers today can produce a gigawatt of capacity in a year. Economy of scale is the key to competitive pricing, which puts smaller factories at a disadvantage. Those smaller plants can be profitable through vertical integration. SolarWorld is a good example. Real production economies can be realized by putting the entire supply chain, from silicon feedstock to plant installation, under one roof.
A large segment specializes in silicon material production, including Hemlock in the United States, Wacker in Germany and many others in Norway and East Asia. The global silicon feedstock capacity was estimated at 0.23 million metric tons (0.25 million tons) in 2010. Nowadays more silicon goes into PV module production than into electronic chips. Globally, the business exceeds 15 billion euros.
A modern equivalent of the machine-tools industry is the turnkey fab segment: companies that can build a ready-to-run automated factory for producing PV modules. Solarbuzz estimates that for 2011, more than $15 billion will be spent to expand manufacturing capacity in ingots, wafers, cells and modules. Thirty percent of that is expected to go for crystalline silicon and 70 percent for thin-film modules. Almost 80 percent of this year’s thin-film investments might go into CIS and the amorphous silicon and multicrystalline silicon segments.
At year’s end 2011, a new production capacity record for a single company is expected: JA in China is likely to ship more than 3 GW of silicon cells.
Finally, the global market for inverters now totals about $6 billion. DC/AC conversion efficiencies above 98 percent are today’s commercial standard.
At the close of 2010 wholesale prices in Germany, for TÜV-certified modules, reached —
- €1.38($1.93) per watt for CdTe (€0.80 spotmarket);
- €1.55 ($2.17) for silicon modules from China (€1.24 spot market); and
- €1.75($2.45)for silicon modules made in Europe.
It is no secret that the cost advantage of the Chinese modules reflects undervaluation of the Chinese currency with respect to both the euro and the dollar.
System prices (without storage) varied between €2.10 and €2.90 ($2.94 and $4.06) per watt. Economies of scale meant that larger systems were cheaper per watt. On the spot market, system prices down to €1.60 ($2.24) could be found. This is down from €5 ($6.99) as recently as 2006.
In early 2011, the German feed-in tariff (FIT) was set at 28.74 eurocents ($0.40) per kilowatt-hour for building-integrated systems and 21.11 euro- cents ($0.30) per kilowatt-hour for ground-mounted arrays. Grid parity will be achieved because PV costs will drop more quickly than other sustainable sources of electricity. During 2011, the German FIT will drop to about €0.25 ($0.35) per kilowatt-hour, while the average cost of conventional electricity will increase 8 percent, from €.237 per kilowatt-hour to about €.256 ($0.33 to $0.36). So grid parity in Germany is about €0.25 — and it’s happening right now.
For 20 years, Wolfgang Palz, Ph.D., managed renewable energy development for the European Union Commission in Brussels.