Inside TSMC's 16.5% CIGS module world record

pv magazine: TSMC Solar’s 16.5% module record is a considerable improvement on its previous record of 15.7% for a full sized module. To what does TSMC attribute to the improved conversion efficiency at module level?

Wen-Chin Lee: Our recent champion module efficiency improvement was driven by engineering of the thin film absorber layer to deliver property improvement; module design changes reducing inactive area; and process tuning and tool design to achieve higher uniformity of thin film across the module area.

Uniformity of commercial-size modules is always critical to achieve high conversion efficiency and TSMC Solar’s expertise in process control and tool design has been able to deliver continuous improvements in uniformity.

Manz recently attributed some of its recent efficiency gains and 16% world record module in part to post-processing of the CIGS layer. Is that something that TSMC is looking at?

We have looked at post-processing improvement opportunities but believe there will be greater rewards in focusing on inactive area reduction, absorber/junction quality, interconnect evolution and optical enhancement in the medium term.

TSMC reports that it is targeting the North America MW-scale market with the Model C2HV modules. Why is this the case?

Marc Spaulding: The C2HV product is targeted at the North America market because it has UL 1000v certification required in that market, which requires UL 1000v-certified junction-box assembly and module.

The North American utility-scale market has transitioned quickly from 600v system voltage designs to 1000v. Although IEC certified modules also support 1000v system operation, the UL 1000v standard is more rigorous and so a specific product needed to be created to meet those requirements.

Beyond these technical reasons, North America is one of the top utility-scale markets in terms of size and growth. In addition, TSMC Solar modules are not subject to the special trade duties applied by the USA and Canada to crystalline silicon (c-Si) modules made in China or Taiwan.

What are the other key markets for TSMC Solar in 2015?

Europe and Africa remains TSMC Solar’s largest markets, as has been true since our start of commercial production in 2012. In addition Taiwan, our home market, remains important while we are also developing Japan, China and Southeast Asia in 2015.

What is the run-rate TSMC currently producing at?

Our current capacity is 100MW, and we run at that capacity except in the slow seasons and when we prioritize efficiency improvement work. Overall, even though we have greatly improved our module efficiency over the last two years, we still see lots of potential to be captured. We manage our capacity to ensure continued growth of our customer base at steady rate of two-to-three times each year and that still allows us the opportunity to use significant capacity for R&D work.

What is the schedule for ramping production?

When we expanded our capacity to 100MW in mid-2014 we set our target for our next expansion in 2016. That continues to be our planned timing, with the scale to be determined by our efficiency and productivity progress and market conditions.

How would TSMC describe the market conditions for thin film solar modules at present?

We don’t see the thin-film market as distinct from the overall c-Si dominated market. Our modules have CIGS-related specific advantages, such as attractive appearance in residential applications and high-energy yield in hot environments. However, c-Si is present in all those markets and still the mainstream technology. Years ago, "thin-film" was associated with a "low efficiency, low-cost" value proposition, or with niche applications.

However, our production modules have up to 15.1% efficiency, and up to 5% advantage in energy yield versus c-Si in most environments. That means our modules are competitive directly with mainstream polycrystalline silicon modules.

The TSMC world record was confirmed in testing carried out by TUV SUD and was produced on manufacturing equipment in Taichung, Taiwan.