Solar Power Optimizers Gaining Market Share

In some ways, the recession may turn out to be a boon to the industry having allowed a number of companies that were, until recently, operating in stealth or R&D mode to strengthen their products and enter the market just as it's on the cusp of recovery. In few areas has this been more true than the relatively young micro-inverter and maximum power point tracking (MPPT) market.

A diverse market, the landscape includes micro-inverters like those offered by Enphase Energy and Direct Grid Technologies, output maximization products from National Semiconductor and SolarEdge, as well as DC parallel technology like that being developed by Sustainable Energy Technologies and eIQ Energy. In total, IMS Research expects this space to represent US $700 million in yearly business, just under a third of the projected value of their inverter space as a whole, by 2014.

While the technologies in each one of these areas differ drastically, the purposes remain the same: get as much electricity as possible out of a given solar installation.

Micro-inverters

Micro-inverter technology seems simple enough on the surface: Attach a small device to every panel in a solar installation that converts the DC power output from the panel to AC power immediately, eliminating the need for a central inverter and doing away with what is known as the Christmas tree light effect (when one panel goes down the entire system does too).

One of the biggest players in this space currently is Enphase Energy. The company released its micro-inverter in late 2008 and since then has shipped more than 100,000 units. The original target market for the product was the residential space, but Raghu Belur, the company's vice president of marketing, said that the product has become popular with commercial project developers and he's gotten inquiries from developers interested in using Enphase's product in utility-scale installations.

This has led the company to release a new model, the D380, specifically for some of these larger applications.  Belur said that it's been a steep learning curve to get the product to this point and all the new players in the space will have to go through similar processes.

“When the benefits of a product are as tangible as those of micro-inverters it's expected that it will create a competitive situation. To date we're the only commercially available product in this market with 100,000 inverters sold. We welcome competition. It's good for the market. Having said that, there's a lot of learning that takes place across the board at a company from design to manufacturing to customer support and we have that broad learning experience,” Belur said.

Watch a video interview with Raghu Belur here.

A new entry in the space is Direct Grid Technologies. A spin-off of Island Technologies, the company is working to capitalize on a history of making equipment for the utility space.

Frank Cooper, president of Direct Grid, said the company has developed a unique design where the circuit board acts as the inverter's transformer and can conduct 700 watts. He said that the company is making a big commitment to solar and micro-inverters.

“We aggressively are targeting 10% of this market. We already have commitments in the area of 300 megawatts of deployment over the next three to four years,” said Cooper. “This is an OEM play for us. We're a volume manufacturer and we've been on utility and the grid side of things. We know the average selling price will come down as it always does, and we'll be able to keep pace with that.”

Watch a video interview with Frank Cooper here.

This space isn't limited to pure play companies, however. SMA, one of the world's largest inverter manufacturers is also getting into the micro-inverter game. It recently acquired a micro-inverter technology platform from OKE Services, which the company plans to develop and release in the next year. Jeffery Philpott, SMA America's director of marketing said that there is definitely a niche that micro-inverters are better suited to fill than traditional string inverters.

“For us it's not really a question of micro versus string. We've found that there are applications that are appropriate for micro-inverters such as less than ideal array orientation, shading issues or small systems under 1 kilowatt,” Philpott said. “So we really see it more as a complimentary device to our string technology.”

Watch a video interview with Jeffrey Philpott here.

On-panel Electronics

While they still rely on a traditional central inverter, new on-panel electronics that accomplish many of the same goals as micro-inverters are popping up as well.

One of the first companies out of the gate in this area was National Semiconductor. Its SolarMagic product is designed to work in conjunction with central inverter string architecture, but use its proprietary built in electronics to reduce the effects of shading or panel mismatch on the overall performance of a system.

John Giddings, SolarMagic global business development manager, said that the pause in growth that the solar industry is expecting this year was a boon for this space because it allowed strong companies to dial in their new products and present the value proposition to the industry effectively.

“The solar industry has been growing very strongly, for decades in fact. But finally it's gotten to the point where the market is mature enough to embrace new innovations and [the market is] large enough that it's attractive for companies to go after,” Giddings said. “So we can take advantage of this pause and do a lot of training and development with our customers.”

Giddings also said that the short-term slow down allowed National to look at acquisitions.  Last month at Solar Power International the company announced the acquisition of Act Solar, whose patent-pending technology, complements central inverters by dynamically re-circulating small amounts of energy as needed by using a technique for power tracking that works by injecting energy into the string as opposed to traditional DC-DC voltage converting approaches.  Early field tests and historical modeling have shown that this solution can cumulatively deliver 40 to 80 percent more power over the operating life of a solar panel installation. 

Watch a video interview with John Giddings here.

SolarEdge has burst onto the scene in last six months with a similar product. The company, which recently received a large investment from GE, is headquartered in Israel and launched its product in the last few months. The company said that its Smart DC ASIC technology and active electronics enable increased production of clean, grid-ready energy at a lower cost-per-watt than any other competitive offering.

Lior Handelsman, SolarEdge's vice president of product strategy and business development said the company's power harvesting architecture bypasses the need for a traditional central inverter by seperating voltage management from power conversion.

“The system is built on the principle of dividing the DC function of the inverter from the AC function. We embed power electronics at the module level to harvest up to 25% more energy,” he said. “It eliminates the constraints you have in a standard PV system. You are no longer bound by the under and over voltage system design issues.”

Watch a video interview with Lior Handelsman here.

Parallel Technologies

Parallel DC-to-DC technologies are also emerging in the MPPT landscape. These technologies don't involve on-panel electronics, but rather rely on parallel DC stringing to reach similar ends. The technology can be thought of as tributaries feeding a river.

Sustainable Energy Technologies is pairing this technology with its own low-voltage central inverter. The company plans to manufacture its Paralex systems in Canada in order to take advantage of the feed-in tariff authorized under Ontario's Green Energy Act.

According to the company's vice president of product development Brent Harris, the Paralex system's advantage is that it takes less time to install than other systems.

“The system gives you the benefit of maximum power point tracking at low voltage without having to have electronics on the module. The key feature is our proprietary inverter that boosts low-voltage from the panels to high-voltage for the grid,” Harris said.

Watch a video interview with Brent Harris here.

eIQ Energy emerged from stealth mode in September 2009. The company offers a similar parallel DC-to-DC boost converter system called Parallux, which takes high-current low-voltage power from the panel and transformers it to a high-voltage low-current form for the grid. Gene Krzywinski, eIQ's CTO said that concerns over the reliability of these types of technologies, at least in eIQ's case may be overstated because of the components that are being used.

“We enable the centralized inverter and we believe in the centralized inverter,” he said. “The eIQ system is not based on new science. The components that we're using are very well known and they're very well characterized. They have been in power supply systems, systems for telecom, the military and in PCs for years. What we've done is essentially over-designed the product with these well characterized components to mitigate failures.”

Watch a video interview with Gene Krzywinski here.

Market Outlook

More than 2.5 GW of PV inverters were shipped in the third quarter of 2009 according to IMS Research. This record quarter marks an impressive recovery for the market, which had stalled in the first half of the year.

According to IMS' Ash Sharma, a very small amount of that 2.5 GW — approximately 50 MW — was attributable to the micro-inverter/MPPT space. However, he said, the growth prospects for the space are positive.

Expectations are that roof-top installations affected by shading will be the most likely market to initially adopt these technologies.

“For these to be successful, issues of cost and concerns about reliability need to be addressed. It is likely however that an increasing number of PV module companies will look to partner with micro-inverter and distributed MPPT companies in order to provide AC modules and differentiate themselves from the competition,” Sharma said.

IMS analysts also said that initially the big growth in the space is expected to come from the pure play micro-inverter area, mainly because that segment got to market first. In the longer term, however, the MPPT side is expected to capitalize on having the benefits of the micro-inverter but little to none of the reliability issues because the technology works in conjunction with proven centralized-inverter technologies.

With all that's happening in the space, there is no doubt that both MPPT and micro-inverters will have a place in the future solar market.