SunSil Drives Electronics Deeper Into the Solar Panel

Coaxing maximum output from each silicon solar cell

Eric Wesoff October 25, 2010

Eric Wesoff

Editor-at-Large
Greentech Media

Eric Wesoff is Editor-at-Large at Greentech Media. Prior to joining GTM, Eric Wesoff founded Sage Marketing Partners in 2000 to provide sales and marketing-consulting services to venture-capital firms and their portfolio companies in the alternative energy and telecommunications sectors. Mr. Wesoff has become a well-known, respected authority and speaker in these fields.

His expertise covers solar power, fuel cells, biofuels and advanced batteries. His strengths are in market research and analysis, business development and due diligence for investors. He frequently consults for energy startups and Silicon Valley's premier venture capitalists.

Sunsil of Denmark has upped the technology ante in the integration of PV solar modules and power conditioning electronics. While the herd of distributed electronics companies, successfully led by Enphase in microinverters and SolarEdge in panel optimizers, are integrating their circuits at the junction-box and panel level, SunSil looks to commercialize a panel with electronics deep in the module itself.

Erik Hansen, the CEO, invented this design ten years ago in an effort to get the maximum output from each solar cell within a panel. Solar cells still have a wide variation, according to Hansen, with cells varying in output up to plus-or-minus ten percent and requiring a binning operation.

Microinverters and panel optimizers maximize output for each module; SunSil's design goes a step further and adds their "dynamic microcell controller" at the solar-cell level within the module and addresses this cell variation, as well as panel shading and panel soiling. Maximum Powerpoint Tracking is being done at the cell level and the panel puts out alternating current.

Sunsil takes a backside-contact, 17-percent-efficient solar cell, scribes it with a laser and breaks the cell into sub-cells. Each solar module uses 576 sub-cells, along with 48 DC-to-DC converters.

With production help from Dutch firm Eurotron, SunSil is building a 300-watt, 230-volt AC module (ACM) -- one that produces 20 percent to 40 percent more kilowatt-hours per year than a standard module. Hansen sees this module design as more effective in residential solar installations with the inverter opening earlier in the morning and closing later in the evening.

Hansen claims inverter efficiency of better than 96 percent, using space-grade components. The end product is guaranteed for 25 years.

The firm's business model is still in flux: Hansen is considering whether to be a module supplier or to license the technology. The module is priced at 900 euros for the 300-watt module in 2011. SunSil expects to allow a price reduction of at least 8 percent per year, according to the firm.

Hansen claims that this system produces higher yields, lower initial costs and lower maintenance costs. The firm is coming off an active showing at Solar Power International and looks to raise between $11 million to $20 million in venture backing.

Another startup, tenKSolar, is also working on cell-level MPPT and combining that with a reflector system (see image below).

In either case, both these companies face the challenge of proving their value proposition in terms of energy harvest and product cost. Questions about reliability can be overcome, as evidenced by the uptake of microinverters and power optimizers.

The issue of bankability is another story: these are single-sourced designs from young companies with fragile balance sheets. They will require strong partners, new sales channels and lots more cash to get their products to market and to scale-up.