MiaSolé, in the vanguard of California’s new thin film solar manufacturing start ups, has just made an efficiency advance that gets thin film back into competition with traditional solar. The National Renewable Energy Laboratory has independently confirmed a 15.7% efficiency of the company’s large area production modules (1 square meter in size).
This effectively cuts the gap between thin film from copper indium gallium selenide (CIGS) with traditional polycrystalline silicon module. Most types of thin film have been above 10%, but not close to 15%, and that is in lab conditions. By contrast, MiaSole’s panels were measured on the production line.
“This is a significant accomplishment as it represents the ability to manufacture full scale CIGS modules with efficiencies equal to or better than that of polycrystalline silicon modules available in the world today but manufactured at a thin-film cost structure,” said CEO Dr. Joseph Laia. MiaSolé makes panels used in large-scale solar projects, and is expected to ship 22 MW this year.
When it was under development a few years ago, thin film promised cheaper manufacturing prices per watt of solar production than polycrystalline silicon.
Thin film has lower “efficiency”, which means it takes more square feet of module to make the same watts as traditional panels. But since they were going to be so much cheaper, it didn’t matter.
MiaSolé’s manufacturing process deposits CIGS on a flexible stainless steel substrate and produces all of the layers required for its highly efficient solar cell in a single continuous process. Similarly, most types of thin film can be very efficiently produced, resulting in lower costs.
But then in 2009, traditional polycrystalline silicon panels prices dropped dramatically due to the ramp up in Europe to meet the Kyoto Accord, with the resulting feed in tariffs offered.
The price drop edged out the former competitive advantage of cheaper thin film. By 2010 traditional solar was close to $1 a watt. The collapse took out some solar thin film leaders like Applied Materials, and threatens Solyndra, an innovative recipient of DOE Recovery Act loan guarantees.
Now, this advance in thin film efficiency marks another step forward for thin film.
“This is a very exciting result, especially when it comes so soon after the previous 14.3% achievement from last September,” NREL solar researcher Dr. Rommel Noufi said.
“An almost 1.5% absolute increase in efficiency in such a short time on a continuous roll-to-roll manufacturing line is impressive and demonstrates good process control and a validation of the MiaSolé approach.” This achievement significantly narrows the efficiency gap between manufacturing performance and cells produced in the laboratory (20.3%), Dr. Noufi pointed out.
It also moves CIGS technology well on its way to achieving the DOE’s target of $1 per Watt for photovoltaic systems, he said.
Update: MiaSolé pointed out an error which I have now corrected:
“Just wanted to point out that your comparisons to efficiencies of c-si panels is dramatically off base: SunPower highest efficiency panels are their E19 series which has an efficiency of about 19% (they have reported a record CELL efficiency as high as 24.2% –much smaller size than a module).
Traditional c-Si panels are not closer to 20% efficiency. On the contrary, the average is 14-15% efficiency. What is exciting about this story is that Miasole’s reported efficiency of 15.7% put their thin film tecnology right on top of today’s c-Si traditional panels. However, their panels use thin film technology which has a much lower cost!”