The Advance of Transformerless Solar Inverters – An Opportunity Lost

It’s always nice to be proven right, but sometimes the ones that got away just gall me.

Four or five years ago we developed a business case with a large Japanese battery manufacturer to bring their solar inverter products into the US market. We would sell, they would build. At the time they had roughly 50% of the Japanese grid-tie industrial size solar installation market for inverters, and a sizeable share of the residential market, and wanted to get into the growth markets in the North America, as the Japanese growth had plateaued.

We had one of the largest US solar system providers agreed in principle to switch to our products, we were planning to certify them to the UL spec, and build them on the Japanese production line for sale in the US. We would have been the low price leader out of the gate.

How? First off, we had a very mature engineering and manufacturing plant in Japan, we had a full range of product – led by a 3.5 kw product for the residential market and a 10 kw modular product for the industrial market (before anyone here had thought about productizing larger sizes). And we had transformerless inverters. We had already started discussions with sources in UL about bringing that technology into the US. In 2001.

Our “best-price” scenario way back then was about $0.50/kw for our residential product, $0.65-$0.75/kw for the off the shelf price. For those of you who might be skeptical, that INCLUDED a nice gross margin. Our partner had pioneered transformerless inverters in Japan in the early to mid 1990s, and by the time they met us, this type was fairly standard throughout that market.

After getting the green light, the project was killed shortly thereafter when our Japanese partner ran into financial problems in other parts of the company, and was forced to re-focus their efforts away from the solar energy division.

I was reminded of all of this recently when a friend of mine sent over a presentation from an energy tech startup talking about advanced, low cost, lightweight inverters. When pressing them about how they could do this, they explained that they had no transformers. So I went do some research, and low and behold, not two months ago Magnetek announced the UL listing of their transformerless solar inverter, and then I noticed recent SMA articles on the now transformerless Sunny Boy String solar inverters in Europe.

“January 4, 2006 Magnetek, Inc. today announced that its indoor and outdoor transformerless Aurora™ Photovoltaic (PV) Inverters have been listed by the California Energy Commission and meet the latest National Electrical Code (NEC) as well as Underwriters Laboratories’ (UL) 1741 standards.”

It’s a shame our project didn’t go forward, but I’m glad the North American industry continues to drive costs down, even if we’re a bit behind the EU and Japan.

2 replies
  1. Anonymous
    Anonymous says:

    Neil,The advance of solar technology balance of system materials is something that is often overlooked in the solar industry which focuses far too much on efficiency ratings at a standard laboratory irreproducable lab condition rather than looking at real world needs. That symptom often transforms (no pun intended) itself into a lack of vision on the balance of systems which are critical real world components of any solar system. Sometimes its just too early in the curve to introduce a technology which the industry is not ready to validate. That's why we need to constantly challenge the paradigms of our industry. ICP Solar's amorphous 6% cell recently outperformed a 15% crystalline module of similar size in real world tests. Do you think for a second the industry is ready to accept these statements as relevant? So just as you found a wall in trying to introduce the notion of a transformerless inverter in the US, others behind you will face the same situation in other technologies, until some other country (usually Japan or Germany) becomes the early adopter. That's the reality of today's PV industry in my opinion.Sass PeressICP Solar

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