Tigo Energy will get approximately 75 percent of its sales in 2011 from commercial and large-scale solar projects, a shift that underscores the rapid growth in the market for solar electronics.
To date, Tigo’s technology -- which can boost the power output of solar arrays by 6 percent to 12 percent -- has largely been incorporated into residential solar arrays. Approximately 70,000 homes to date sport Tigo’s tech.
This year, the company will participate in six- and ten-megawatt-sized projects. Expect to see it involved in 500- and 600-kilowatt commercial arrays, too.
“It will be a much bigger part of our mix,” said Jeff Krisa, vice president of sales and marketing. “We know the cost argument works on these kinds of projects.
“One 500-kilowatt system equals a lot of residential ones,” he added.
Tigo will also drop the cost of some of its components by 33 percent to 50 percent through better integration with solar panels.
Solar electronics vendors like Tigo, SolarBridge, Azuray, National Semiconductor Petra Solar and Enphase Energy share a common goal: to wring out inefficiencies in conventional solar arrays. Where they differ is how they accomplish that goal. The cost, benefits, flaws and strengths of each approach will likely be a hot topic in solar over the next two years.
. We will talk quite a bit about this at the Networked Solar Conference taking place January 25 and 26.
Tigo’s technology essentially deceives the inverter through two components: its solar Maximizer, which gets clipped to the back of a solar panel, and the Maximizer Monitoring Unit, a centralized computer that communicates with the Maximizer.
Solar inverters are designed to accept power from a string of panels at a single current level. As a result, dirt, shade, clouds or a hardware malfunction that curbs the output of one panel brings down the output of the whole string.
“Generally, 20 percent of the panels are the weak ones,” said Krisa.
Energy that better performing panels produce but can’t deliver through the inverter instead gets dissipated as heat. (Microinverters like those from Enphase eliminate the mismatch problem by giving each panel its own inverter.)
Tigo captures data on the current, voltage and temperature of individual solar panels. The Maximizer Management Unit then ranks them by optimal performance by examining their impedance, or overall resistance. It then sets the inverter to the current from the maximum performing panel.
Panels performing at a sub-optimal level would generally force the inverter to revert to a lower level. Instead, Tigo routes the power from these panels through the Maximizer, which tunes voltage and current output to make the performance appear similar to the top panel. Put another way, the low-performing panel gets virtually re-sized rather than the other way around.
“The string’s influence on the panel is no longer there,” Krisa said.
Tigo’s system works at a 99.6 percent efficiency level; thus, little of the energy harvested gets consumed by the Maximizers. Under its own tests, Tigo has found it can boost power output by 6 percent under optimal conditions for solar panels (e.g., midday, June, cloudless sky, well-designed solar array) and 8 percent to 12 percent in more ordinary conditions.
The cost of the Maximizers comes to around 16 to 17 cents per watt on a big array, which makes the cost of the Maximizers and a standard inverter (20 cents or less per watt for that) cheaper than a microinverter, Krisa argues. The technology requires fewer components than microinverters, he argued.
The cost will drop later this year with integrated Maximizers. Right now, the Maximizer comes separately and is attached to a solar panel by an installer. Suntech and others are looking at common interfaces for maximizing technologies.
“Our total balance of system costs are lower because we can layer onto the cost of a large, central inverter,” he said.
In all, Tigo claims its system pays for itself in two to three years. The company was founded three years ago by ex-Intel and Applied Materials execs who realized that solar had yet to be fully automated.
Tigo also offers an online service that helps pinpoint failing solar panels.
Enphase and other maximization companies, of course, disagree and point to data on reliability and cost benefits of their own. MJ Shiao at GTM Research notes that DC maximization can cost less because of lower component counts, but you also have to factor in installation, familiarity and other issues. The circumstances can dictate which technology is cheapest.
Over the next two years, this should be an interesting ride.