HelioVolt said Monday it has produced thin-film solar cells that can convert 12.2 percent of the sunlight that hit them into electricity.
In results to be presented at the IEEE Photovoltaic Specialists conference in San Diego, Calif., the company said it produced those cells in six minutes using its FASST reactive transfer printing process.
Analysts called the news a step forward in the race to commercialize copper-indium-gallium-diselenide, or CIGS, but said the company is still a few miles away from bringing that efficiency to the market.
“That’s a very good number,” said Paul Maycock, president of solar-electric consulting and research firm Photovoltaic Energy Systems. “It’s higher than anything available, so it’s very exciting. It’s what we’ve been expecting from CIGS at high production rates [but haven’t seen], so it’s very exciting.”
The process time also is “very fast” and sounds about the right speed for the market, as First Solar produces full-sized panels in almost the same amount of time, Maycock said.
Advocates believe CIGS has the potential to give cadmium-telluride films – such as those produced by First Solar, by far the world’s largest thin-film solar company – a run for their money. As CIGS companies are fond of pointing out, laboratory tests have shown efficiencies of up to 19.9 percent for CIGS cells, compared with a record of about 16.5 percent for cadmium-telluride.
But the reality outside of the labs has been different.
So far, First Solar (NSDQ: FSLR) has reached average cell efficiencies of 10.6 percent, according to a Piper Jaffray research note referring to numbers from the end of last year, and has reached an annual capacity of about 300 megawatts, according to the company's annual report, while CIGS manufacturers have yet to reach significant commercial production.
“Why doesn’t First Solar have competition?” has become a common industry refrain.
And, up until now, none of the thin-film competitors has claimed they would have higher efficiencies from the get go, although they all expect their efficiencies to improve over time.
Global Solar Energy, which opened a 40-megawatt CIGS factory in Arizona in March, expects to produce cells of about 10 percent efficiency, and Miasolé, which plans to expand its capacity from 40 megawatts to 100 megawatts next year, claims its panels have efficiencies of between 9 and 10 percent.
HelioVolt’s test results could indicate a potential to out-convert its competitors.
“This is the first time we’ve had third-party verification that we’ve publicly announced that shows that the process is meeting its goals,” said John Langdon, vice president of marketing, in a phone interview. “It means that thin films will move into an efficiency arena similar to the polycrystalline silicon devices, potentially for a much lower cost. It means we’re on schedule and we’re meeting our milestones and we plan to meet our next ones [of reaching full-scale production and ramping up our production volume] too.”
While the results might be an indicator, however, they aren’t yet proof.
According to Langdon, the 12.2 percent efficiency came from a “champion cell,” meaning it represents the highest efficiency, not the average efficiency, that the company has produced.
Austin, Texas-based HelioVolt is making cells on a pilot line, not a production line that would represent commercial volumes, and also is making them 10 times smaller than their ultimate market-ready size, he said. Making product larger comes with some risk, as technologies don’t always perform the same at different sizes.
The cells also aren’t scribed and interconnected to be made into panels, a process that Maycock said often eats up 10 percent of the efficiency.
“You’ve got to do it day in and day out; you’ve got to be in production,” Maycock said. “And it cost First Solar almost a year before they could ship cells that could be put into modules. People are learning from First Solar, so it’s not a mystery, but it just takes time.”
Still, Langdon said HelioVolt is seeing a very low variation in results and expects its initial products to range between 10 and 12 percent.
“Everything is treated very similarly and although eventually I think we will produce efficiencies better than 12 percent, I think it is representative of what we can start with,” he said. “We’ll have the same issue that any manufacturer does, but the process itself is very robust and repeatable.”
The company is producing hundreds of cells at its pilot plant, and is constantly upgrading its equipment and fine-tuning its process to produce more each day, as well as testing the packaging and interconnection, he said.
Langdon added the process is achieving “extremely high” yield, but wouldn’t disclose any numbers yet.
“It’s taken a long time just to build our equipment to make it work, but we’re very pleased now with how well it does work,” he said, adding that the line was first thought up six years ago. “We think this is representative of what production will be and I think, in the long run, we can do quite a bit better than this.”
Another challenge is cost.
In its fourth-quarter earnings, First Solar reported a manufacturing cost of only $1.12 per watt. Langdon said HelioVolt’s per-watt costs will be higher at first, but will fall below First Solar’s once it reaches similar volumes.
“They weren’t anywhere near that cost when they first began shipping either,” he said. “We see a similar curve. We want to drive volume up as quickly as we can and drive up the learning curve as quickly as we can. We think we can ultimately drive cost below $1 per watt. How far exactly, I don’t think anybody knows. We certainly have the potential to be the most cost-effective thin film.”
Maycock forecasts that First Solar will reach a cost of 75 cents per watt, “if not lower,” by 2010. “That’s so low that there’s nothing else out there that’s going to beat them right now,” he said.
Langdon acknowledged the risk his company faces, but indicated that the test has bolstered HelioVolt’s confidence.
“It’s a risk, but I think we have a lower risk than everybody else because we have a fundamentally different and robust process,” he said. “I think most of the risk now is the engineering and can we get everything in the same room at the same time and get it all together.”
All things considered, Travis Bradford, president of the Prometheus Institute, a Greentech Media partner, called the news “encouraging.”
Panel efficiencies of 10 percent are required “just to get in the game” now, he said, adding that the baseline could grow as other players make improvements.
“It sounds like they are still a viable candidate for eventual success,” Bradford said.
Still, HelioVolt has a number of difficult steps left on the road to commercialization, he said.
“Progress in this is good, and they have a wonderful process and product on the pilot line, but scaling things up is also difficult,” Bradford said. “They’re not done yet. There are meaningful risks ahead of the company, but now with this announcement, there are also meaningful risks behind them.”