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Solar startup Stion slips slightly out of stealth mode

03 June 2008 | By Tom Cheyney | Chip Shots

Although it still won't divulge much about its process or materials set, San Jose-based next-gen thin-film photovoltaic startup Stion has come ever-so-slightly out of stealth mode. Unlike a few months back when I blogged about the stealthiness of Stion and used whatever scraps of information and speculative research I could dig up, the company has revealed a few more details during a presentation at Greentech Media's PV Annual 2008 conference last week and has just announced the hiring of two new vice presidents.

Frank Yang, Stion's manager of business development, sent me a copy of the presentation as well as the press releases about solar industry vets Robert Wieting and Steven Aragon joining the company. Wieting takes on the VP of R&D role after a stint at Regenesis Power, a turnkey PV systems firm. Before that, he worked with Stion's president/CEO Chet Farris at Shell Solar, where Wieting ran the tech team that set up the first fully qualifed, megawatt-scale manufacturing line of copper indium (di)selenide (CIS).

Aragon comes to the startup as VP of engineering, the same role he held at his previous job at Daystar Technologies, one of the many companies vying for CIGS thin-film legitimacy. Aragon worked at Advanced Energy before the Daystar gig, where he helped get that company's solar product lines going.

As for the presentation, the company offers the propositions that it "must be able to differentiate against major players" and that the "combination of cost and efficiency" are critical. It's targeting $3 per watt-peak for installed system cost (that's unsubsidized grid parity), or about 15 cents kilowatt-hour in the US. Unlike many companies in the thin-film PV domain, Stion says it doesn't want to get into "the equipment development business" and wants to use "proven high volume, low-cost deposition technologies." It also plans to deploy what it calls "readily available, environmentally benign materials."

Stion's primary market focus? "End-of-wire large rooftop systems" of 500 KW to 1 MW. It plans to "drive cycles of learning with a data-driven statistical approach" (something definitely not unique to the firm and sounding very semiconductor-ish) and to work in parallel on R&D, engineering, reliability and manufacturing.

Although Stion's scions will not say what kind of thin-film material they are using, speculation has centered on some application of quantum-dot technology, given the background of CTO Howard Lee and his work in that area. But the presentation does include two slides that shed a bit more light on what they're up to.

The first one shows a chart that posits Stion's single- and multijunction inorganic whats-its TFPV cells as having the "highest theoretical efficiency" of any nonconcentrator PVs out there. The company claims impressive theoretical maximums of 33% for its single-junction cells and 50% for its multijunction cells, with bandgap energies around 1.5 eV. The so-called company claims its product development roadmap includes efficiencies of >15% for the first generation and >20% for the second.

A slide depicting its "cutting-edge fourth-generation technology" reveals a generic film-stack cutaway, with two sets of transparent conductive oxide (TCO), window, absorber, and back-contact layers sandwiched together between two pieces of glass. The caption inelegantly reads "materials and device structure allow for combination of high efficiency and utilizing proven production technologies," but offers no film thicknesses or process flow info, let alone the materials components of any of those four layers. Since molybdenum is the most common back-contact film used in many TFPV processes, can we at least assume it might be used in Stion's stack as well? Apparently not...yet.

The presentation continues with a slide titled "Pursuing lowest installed system cost, showing Stion's gen-1 and gen-2 products comparing favorably, in terms of efficiency versus cost/watt, with thin-film leader First Solar, silicon stalwarts Sharp, Kyocera, Evergreen, Suntech, Sunpower, and Sanyo, as well as amorphous-silicon thin-film pioneer Uni-Solar. But the chart includes no percentages or dollar amounts on its y- and x-axes--the proverbial normalized graph.

The final slide, headlined "Future expansion strategy," says that Stion will "launch US-based production first, (then) partner globally." Whether that means an captive or outsource manufacturing strategy is not clear, although statements (see below) indicate the company will first build its own factories before deciding to do any production on an outside contract basis.

The next line reads "Decentralized approach enables maximum flexibility in changing market." A planetary map features bullseye-like circles colored green signifying the company's primary markets, and circles colored yellow for its secondary markets. The US, Europe, India (or is it Pakistan?), China, and Japan are tagged with the green dots (no surprise there), while South America (specifically Brazil), Southeast Asia (specifically Indonesia), Australia, and North Africa (looks like Libya) carry the yellow markers. The untapped Antarctican market apparently is not a part of Stion's gameplan.

Stion's Yang told Greentech Media last week that the company plans to close its Series C round of financing by the end of 2008, which should be enough to get the company into production, first with a 5-MW pilot facility by 2009 and a 25-MW commercial line the following year. He said the company expects to have its first working prototypes of its high-efficiency cells by the end of this year or beginning of next, and the first products on the market by early 2010.

It may not be much, but at least Stion has shed a little light on what it's up to, even if a few minor details like its enabling material technology remain a closely held secret.