SMA acquires Photovoltaic Microinverter specialist OKE

Is SMA validating the microinverter segment or just playing catch up?

Earlier in September, SMA Solar Technology AG (ETR:S92) announced “plans to launch its own range of module inverters in the coming years” with “SMA increases its technological edge in the photovoltaic market with the acquisition of OKE’s module inverter technology” (Deutsch).

OKE-Services was founded by Henk Oldenkamp in 1983 and has over 15 years of experience in the “Design and development of electronics for photovoltaic solar energy”. “Module-integrated inverter from NKF” by Iris Krampitz and Michael Schmela for PHOTON International reported the OK4 AC-module inverter (microinverter) design NKF Electronics licensed from OKE-Services (OKE) had unit sales exceeding 50000 units in 2002. OKE believes about 80000 OK4 and OK5 units were shipped to grid connected applications by NKF. I was not able to determine when or why NKF exited the microinverter business although one claim is the Dutch government decided to end photovoltaic (PV) subsidy programs.

While the OKE acquisition price was not disclosed, Solarbuzz said:

a consultancy contract was drawn up with the owner of OKE, Hendrik Oldenkamp, with a duration up until September 30, 2012.

Positioning microinverters for small PV systems, SMA said:

Micro inverters are particularly well-suited for the use in small photovoltaic systems of 1 kWp or under. In some larger photovoltaic systems which use string inverters, shading of individual modules and the subsequently lower energy harvest of the entire system can be avoided by equipping and operating those modules with individual module inverters.

SMA does mention optimizing larger systems on a selective module basis. With AC (Alternating Current) Power of 460 to 700 Watts (W), the Sunny Boy 700U is the smallest string inverter SMA offers for the US market today. A typical microinverter has an AC Power rating of about 200 W.

Enphase Energy Co-founder and Vice President of Marketing Raghu Belur observed microinverters had long been validated by their customers, and SMA was yet another entrant into the segment. Poking holes in SMA’s microinverter market segment understanding, many Enphase customers use microinverters in 4 to 6 kW (kiloWatt) residential installations, and Enphase claims a few 100 kW sized commercial installs are beginning to adopt microinverters.

Enphase has been challenged to keep pace with skyrocketing microinverter demand and has used the $22.5 Million funding round to boost production with partner Flextronics International Ltd. (NASDAQ:FLEX).

Another confidential PV industry source thought the SMA acquisition was intended to deflate equity analyst concerns about the distributed electronics threat to SMA’s central string inverter business. SMA leads the PV inverter market and had 38% market share in 2008 (Speech of the Managing Board slide 7). Also, the source noted Mr. Oldenkamp was planning to publish the OK4ALL microinverter design on the internet and grant non-exclusive production licenses “in exchange for paying a small fee.”

I still see a gaping hole in SMA’s product line for a distributed, per module DC (Direct Current) MPPT (Maximum Power Point Tracking) electronics solution targeting the full system capacity gamut of PV installations.

I’ve been trying out blogging software for my new MacBook Air over the weekend in a vain attempt to find a Windows Live Writer (WLW) equivalent. If you happened to notice a snafu post last evening, my attempt to save a draft in ecto resulted in the test snippet being published to the Blog. Ugh! That’s why I prefer to post a draft to WordPress first.


  1. Slim Shady says:

    I thought SMA said (as a comment to an article about Power optimizers) that shading has only a small impact in Aug edition of Photon, and now they need microinverters to adress this “small problem” ?

  2. Greenguy says:

    Shady: I don’t think SMA “needs” micro inverters but it is a great addition to their portfolio. They are doing quite well without them, but every watt counts, wouldn’t you agree?

    They are at the top of their game so it should come as no surprise to the industry that they grab some of the niche market microinverters satisfy.

  3. Ante says:

    Mislim da bi se trebala nastaviti proizvodnja.
    procijena za 2010 cca do 100 000 komada
    Imamo ideju za iskorištavanje malih invertera..
    Ovi nam odgovaraju. Snaga od 200 do 500W.

  4. Son of Liberty says:

    I agree… Shady: Why would a large central inverter manfucturer buy out an innovative micro inverter company and then downplay the potential for the market served?

    Sort of like years ago when Westinghouse or GM would go around and cherry pick innovations, patents, etc. to squelch any potential challege to market share.

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