The notion that grid operators in the U.S. are trying to impose undue costs on the solar industry by asking for advanced grid-management capabilities for PV inverters is “completely wrongheaded” in the eyes of inverter market leader SMA Solar Technology.

“As a matter of fact, many products already support these features without any additional costs,” said Bates Marshall, vice president of the Medium Power Solutions group of SMA America, in an interview with Greentech Media. “The better course is to support the higher penetration rate of PV by improving the grid management technology available in the inverters, so that's our task,” he added.

SMA has plenty of experience in regions where advanced grid-management features are already implemented, first and foremost on its home turf of Germany. Estimates from the Western Electric Industry Leaders (WEIL) indicate that the requirements that a consortium of utilities in the western U.S. laid out in a white paper could add about 10 percent to the manufacturing costs to inverters might even be too high. Marshall considers $150 of added production costs for a typical residential system to be a fair budgetary placeholder -- if the grid operator requires a separate communications channel. But if it uses existing links that don't require new communications interfaces, the cost penalty could likely be eliminated altogether.

In addition to the communications capabilities, the utilities want inverters to support real and reactive power, allow for dynamic VAR injection, and to be able to offer low voltage ride-through as well as expanded frequency trip points. WEIL's white paper also calls for the randomization of timing for trip and reconnection. Most of these features are already supported by SMA products because they are required in other markets, according to Marshall, but “of course, the devil is in the details, and some minor development may be necessary to meet the particular requirements that are implemented, but those are typically limited to firmware modifications.”

The biggest opposition against these new rules comes from companies with more difficulties in technical implementation, namely microinverter manufacturers. “It is a matter of public record,” said Marshall. “It is clear that they are trying to slow down the development of these requirements and to slow down the scope.” He specifically named California-based microinverter manufacturer Enphase, adding: “Our feeling is that the strategy is driven by the fact that their product cannot cost-effectively handle these requirements.”

Microinverter companies which, like Enphase, rely on their products to communicate over powerlines and don't offer a single point of communication into the array are having difficulties, according to Marshall. “We know from the attempts of our competitors that tried to do business in the European market that they are not able to cost-effectively support these grid management requirements because they lack this single point of integration to the array.”

Not surprisingly, SMA is going a different route with its own microinverter that will ship in large quantities by the end of the year. The SMA devices are communicating with each other via Ethernet. And since the inverters are connected in parallel to a multigate device, they will offer a single point of communication into the PV array. Marshall is optimistic that the microinverter will allow the company to win back market share in the residential sector in the U.S. Reports that pure microinverter companies have even made a significant dent in the commercial U.S. rooftop market are greatly overstated. According to SMA: “We don't see that. If you talk to the big developers and integrators, there is basically zero penetration of microinverters in the market.”

Overall, SMA America is quite pleased with its 2013 growth rate in the U.S. While the utility market business is flattening out and it has become increasingly difficult to fill the pipeline, the commercial and residential markets are doing well.

SMA expects a 15 percent to 20 percent compound annual growth rate in these segments in the next few years, which makes them the company's key focus. According to Marshall, the Sunny Tripower product line of string inverters for commercial arrays, which was introduced to the U.S. market in June, is “incredibly successful.” Every unit that can be built is sold immediately, and SMA is working on increasing its production rate. It sounds like the expectation of SMA's management is coming true: the U.S. market, hand in hand with China and Japan, might be able to compensate, at least partially, for the losses felt due to the massive market contraction in Europe.

And at least according to Bates Marshall, the soon-to-be-expected new grid service requirements for inverters will do nothing to slow down PV, or SMA for that matter, in the U.S.


Meet the solar inverter industry's top executives at GTM's annual U.S. Solar Market Insight conference in San Diego in December. More info here.