Researchers around the world are improving solar cell efficiency; however, high efficiency comes with a price and different factors affect their competitiveness. (Jul ’10)
Competitive solar cells rely on climate, efficiency, material and production costs. The fluctuation of electricity prices from different sources and political climates both play a big part as well.
Professor Marika Edoff at Uppsala University in Sweden, an authority in solar cell technology, heads one of the leading teams in thin film photovoltaic research. Thin film is the second generation of solar cell technology, introduced after crystalline technology. “We focus on thin film solar cells because they are cheaper to mass produce. Their durability was questionable, but now they come with a 20-year guarantee.”
The efficiency of solar cells, or photovoltaic cells, on the market often varies between 10-15 percent. Edoff believes solar cells with a higher efficiency will soon reach the market, but additional factors will determine efficiency. “The theoretical limit is about 30 percent,” she said. “I think the public will see an efficiency of 16 percent for modules within a few years when the technology matures. Overall cost will determine the efficiency that reaches the market. Higher efficiency can mean a high cost for the customer. Solar cells need to become cheaper to produce.”
Climate, political decisions and changing energy prices will impact solar cell competitiveness and these factors vary between countries. “Solar cells are a big industry. It will be competitive within the coming two years in South Europe, Africa and the Sun Belt in the U.S. The competitiveness of solar cells is dependent on the changing prices of electricity from other sources. In some countries the solar cells will pay for themselves within one to five years. They are not competitive for all climates. For example, in Germany solar cells are profitable. The government requires utility companies to buy electricity from customers’ personal solar panels. But in Sweden such a subsidy does not yet exist,” Edoff said.
Deputy Chairman Andrew Machirant at the Swedish Solar Energy Association favours subsidies. “It is less about the technology, which is already efficient, than about how you support the expansion of solar power systems in society,” he said. “What we need is an efficient subsidy in Sweden and we don’t have one. When the demand increases the production capacity increases, which reduces the cost. It was the same situation 10-15 years ago for wind power.”
He thinks that Italy is very close to having competitive photovoltaics, arrays of cells. “The price for energy from fossil fuels increases and the price for energy from photovoltaics decreases until they converge. I think that Italy will have reached this convergence in 2012-2013. The sun shines most efficiently for about one to two hours per day, and energy consumption will be high then. Energy from solar power systems can level out those peaks. Photovoltaics become competitive then. In Sweden, with rising energy prices and a 5-10 percent decrease in price per year for the whole solar power system, photovoltaics will be competitive in 2020.”
Solar cells will be a complement to other technologies for energy production. Subsidies can speed up the transition to solar power. With increasing energy prices, the sun provides unlimited potential.
(1 July 2010)
Annette Östrand