It was also the year that direct current (DC) took a back seat to alternating current (AC) after Niagara Falls Power Company chose AC transmission for its power plant.

Although we live in an AC-dominated world, DC seems poised for a comeback, particularly in data centers. Facebook adopted a DC architecture in its Prineville, Ore., data center. SAP spent $128,000 retrofitting a data center at its offices in Palo Alto, Calif., to rely on DC power. In 2010 it cut SAP’s energy bills by $24,000 per year.

ABB, the Swiss-Swedish conglomerate, bought a controlling interest last year in Validus DC Systems, which specializes in DC data center equipment. ABB also opened a factory in North Carolina to produce HVDC (high voltage DC) equipment for delivering power from solar and offshore wind farms to the grid. The Tres Amigas “superstation” will rely heavily on HVDC.

General Electric, meanwhile, bought Lineage Power, which produces DC equipment, and it has talked about using DC to power mining shovels and other heavy-duty equipment.

Nextek Power Systems and the EMmerge Alliance are also promoting DC as a way to cut power in buildings.

Behind the DC drive

What’s driving it? Although AC became the standard for electronic transmission, DC didn’t disappear. It just hid. Servers, large numbers of electric motors, batteries, even ships and airplanes run on DC. Solar panels produce DC power. Wind turbines can produce AC or DC power, but the extreme variability of wind power means that electricity generated by turbines has to pass through battery banks before it gets to the grid. As a result, wind farms are effectively DC.

The landline telephone system runs on DC too, notes Brian Fortenberry, a program manager at the Electric Power Research Institute.

To solve the mismatch, a whole industry of AC-DC converters has been developed. National Semiconductor sells billions of dollars’ worth of chips to convert power. Inverters in the solar industry exist to convert DC from solar panels to AC that can run on the wires in your home.

In data centers, the AC-DC gymnastics top the charts. Typically, AC from the grid has to be stepped down in voltage so it can be routed safely in building equipment. Lower-voltage AC then gets converted to DC so it can go to an uninterruptable power supply (UPS). DC power from the UPS then gets converted to AC so it can go over the wires in the building. Then it gets converted back to DC. Usually five conversions, or steps, downward take place.

By converting grid AC at the door of a data center to medium-voltage DC or converting stepped-down AC to DC at the last possible moment, a data center can cut utility bills by 10 to 20 percent or more, according to Trent Waterhouse, the VP of marketing for power electronics at General Electric.

Validus and others have also eliminated some of the technological hurdles involved in transmitting via DC, namely the monster-sized copper cables.

The same dynamics work in buildings. In a retail establishment, DC power from solar panels could go directly to DC-powered LED lights with not-intermediate conversions that sap energy, according to Nextek. Perhaps not coincidentally, Redwood Systems, the lighting networking company, touts that its technology is actually an example of DC networking.

More savings comes in real estate. DC data centers require 25 percent to 40 percent less square footage than their AC counterparts, largely because computer equipment can connect directly to backup batteries.

In a hypothetical example, a 2.5-megawatt data center power module in the AC world might need 7,295 square feet, Ronald Ranaldi, the VP of sales at Validus, told me last year. An equivalent DC power module might occupy only 5,102 square feet, a savings of 2,193 square feet. What’s more, a single data center might consist of several 2.5-megawatt modules.

“Real estate is often greater than the energy savings,” says Ranaldi. “In large, green field data centers, you are literally eliminating buildings.”

DC won’t take over the world. And not everyone is sold. Google is not taking DC for its data centers in part because of the cost that would be involved in retrofitting their existing architecture. But it seems that an idea that was current when Grover Cleveland was in the White House and Japan was just adopting the Gregorian calendar could make a comeback.

Image courtesy of The Planet

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Arienzo is divulging more details about the company’s technology after giving a short and cryptic description of it at a cleantech conference last week. The technology makes use of pulse amplitude modulation, a concept that has been used in Ethernet equipment and in controlling LED lighting, but now is being applied to solar. ArrayPower, which is based in Sunnyvale, Calif. and founded in 2007, has also lined up $22 million in venture capital funding.

Here’s how it works: each ArrayPower silicon-based device is attached on the back of a solar panel to boost the voltage of the direct current from 60 volts to 208 volts before being connected to three circuits of resistors and capacitors, which send out the current in pulses. Those pulses alone aren’t enough to form the current with the right frequency for an electric grid. But when combining at least four of them, you have the right AC wave to supply to the grid.

“It’s like a symphony where you have different instruments playing and they all come together,” she said.

Conventional power conversion devices are called inverters, and each produces AC at the right frequency. Each inverter typically is paired with about a dozen solar panels, though startups have emerged in recent years to develop microinverters that go on the back of each solar panel. Microinverters can better monitor and adjust the power output of each solar panel, and as a result promise to reduce power losses. But microinverters are also newer products to the market and more expensive than centralized inverters.

ArrayPower’s device, which the company calls a “sequenced inverter,” promises to offer the benefits of microinverters (more power harvested) at the price of centralized inverters, Arienzo said. That’s the idea anyway, since the company hasn’t shipped its products commercially yet. It intends to sell them to solar panel makers, who will assemble them into the panels, and it has lined up one customer who will launch an integrated panel at the Solar Power International conference in Texas later this month. ArrayPower expects to start shipping its devices early next year and will hire a contract manufacturer to produce them.

The U.S. will be the first market, though the company is doing field trials of its gear in Germany to get ready for the commercial launch in Europe. The company’s investors include Partech International, Trident Capital, Draper Fisher Jurvetson and Firelake Capital Management. ArrayPower’s chairman is Kevin Surace of Serious Energy, and its board includes Solaria’s CEO, Dan Shugar.

Photo courtesy of ArrayPower

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Array Converter CEO Wendy Arienzo said at the conference: “Marconi came up with radio and called it amplitude modulation. We are taking a well established technology and applying it to solar.”

Asked about Array Converter’s technology after her panel, Arienzo declined to say more about the company’s research, but said the company plans to make an announcement at the Solar Power International conference next month.

Amplitude modulation involves using radio wave to send information — the technology adjusts the amplitude of the radio wave rather than the frequency (FM) — and Array Converter’s work seems to focus on using pulse amplitude modulation. Pulse amplitude modulation is used in Ethernet equipment and for controlling LED lighting. Eric Wesoff at Greentech Media wrote about the company earlier this year, and patent attorney Eric Lane wrote about the startup’s patents in a blog post.

Array Converter is setting out to develop power electronics that are indeed different than the ones commonly used today to convert DC from solar panels to AC in order to be used on site or feed the grid. Solar systems today use inverters to do the power conversion; the inverter gets its name because its design reverses a conversion process to turn AC to DC (this device is called rectifier).

Although Array Converter hasn’t announced products, its website indicates that the company is working on a modulator and controller. And, yes, the startup promises to deliver power electronics that can reduce the overall equipment and installation costs.

Inverters have been used in solar energy systems for decades. Each inverter is typically responsible for about a dozen solar panels. In recent years, some inverter developers have come up with what’s called a microinverter that is paired with each panel.

The use of microinverter has led to the name “AC panel,” because the DC-to-AC conversion now takes place at the panel rather than at a central inverter that sits in a stand-alone box next to the solar array. Array Converter, incidentally, also calls solar panels that use its devices “AC panels.”

All of these technologies are working on improving the efficiency of converting the electric current – power losses are typical during power conversion. A Google-backed startup, Transphorm, is working on reducing that power loss by using a novel material called gallium nitride.

Array Converter already has lined up investors, including Partech International, Trident Capital, Draper Fisher Jurvetson and Firelake Capital Management.

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But unlike these social media companies, Enphase is manufacturing actual devices (though also software) — buying goods from various suppliers — and that takes a lot of funding to scale up. It has designed a type of inverter that’s distributed for each panel — in contrast to the traditional single central inverter for a solar system — and Enphase says its microinverters are more efficient, safer, and can allow better monitoring. Here’s a look at Enphase Energy’s numbers via its just-filed S-1:

Proposed Maxium Aggregate Offering. $100 million.

Volume. Enphase says it has shipped 750,000 units through May 31, 2011, which represents over about 25,000 solar installations.

More reliable. Enphase says microinverters are 45 times more reliable than central inverters.

Background. Enphase was founded in March 2006 as PVI Solutions.

Financials. For the three months ended March 31, 2011, Enphase generated $18.07 million in revenues, up slightly from $11.59 million in revenues from the same quarter a year earlier. For the full year 2010, Enphase brought in $61.66 million in revenues, up from $20.20 million in 2009. However, Enphase has continued to lose money and has never been profitable. The company lost $9.29 million for the latest quarter, $21.78 million for the full year 2010, and as of March 31, 2011, had accumulated a deficit of $65.8 million.

Growth trajectory. While Enphase continues to lose money, it has been on a growth trend throughout 2010. The company shipped 11,000 units in 2008, 126,000 in 2009, and 414,000 in 2010. For the first three months of 2011, Enphase has shipped 123,000 units, or almost the same as it shipped for the entire year of 2009.

IPO proceeds. Enphase says the $100 million from the IPO will be good for funding the company’s activities over the next 12 months, but Enphase says it may need to raise more after the IPO for R&D, expansion, and acquisition. It’s a rather competitive market for Enphase, competing with large suppliers and sometimes the panel makers themselves.

Installer partners. Enphase says it works with 2,500 installers in North America as of May 31, 2011, and is adding new installers at the rate of about 100 per month.

Manufacturing and suppliers. Enphase works with Flextronics, which assembles and tests its microinverters; Phoenix Contact, which makes the AC cable for its third-generation M215 microinverter system; Fujitsu, for its ASIC; Epcos, for magnetic cores; Cree, for diodes; and TDK-EPC for magnetic components.

Funds raised to date. The company closed a $63 million private round in June last year, bringing the total private money raised to $104 million by the end of 2010.

Who will do well in the IPO? Third Point owns 19.10 percent of shares before the offering; RockPort Capital owns 18.10 percent; Madrone Partners owns 14.80 percent; Kleiner Perkins Caufield & Byers owns 7.70 percent; Applied Ventures owns 6.30 percent; and Bay Partners owns 5.50 percent.

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Power-One said Fat Spaniel’s software for monitoring and analyzing the performances of solar generation projects, from residential solar electric systems to larger commercial installations, is a good fit for the company as it plots for expansion in the U.S. and other markets. The publicly traded Power One, based in Camarillo, Calif., said Wednesday it’s bought most of the Fat Spaniel assets and will merge the software developer’s operation into its own.

Neither company disclosed the acquisition price, so it’s not clear whether the sale is a nice payback for Fat Spaniel’s investors, which included Element Partners, Chrysalix Energy, Applied Ventures, Ignition Partners and PCG Clean Energy and Technology Fund (managed by PCG Asset Management).

Fat Spaniel, a Silicon Valley company founded in 2003, makes money by selling monitoring services to solar energy system owners. It rode the wave of the solar market boom and boasted on its website that it had managed over 3,800 sites, including the San Francisco International Airport, in 23 countries.

UPDATE: David Lincoln, managing partner at Element Partners, told us the deal was a good one for Fat Spaniel because it’s had some tough times growing its business. The pressure to drive down project development costs in the last two years has made developers more stingy about spending money on monitoring services, he said. Fat Spaniel’s services can be more attractive if they are packaged with equipment and services from a large company such as Power-One.

Power-One wasn’t the only suitor. Companies that showed interest in Fat Spaniel included makers of microinverters and other power electronics, as well as those in the monitoring business, Lincoln said. He declined to discuss the profits the investors were able to make from selling Fat Spaniel. But he added, ”Even though no one was writing home to their mothers about the outcome, every one was pleased that we were able to get the deal with Power-One.”

Fat Spaniel started off offering monitoring services to owners of solar electric systems at homes and businesses, and it talked about targeting the utility-scale power plant owners last year. For the utility market, Fat Spaniel also was looking at offering software to help developers design power plants. Last September, the company also announced new software that it said could detect and trouble-shoot operational problems and help power plant owners cut maintenance costs by up to 30 percent.

In many cases, solar power project owners have to collect performance data not just to ensure their solar panels are working as designed, but also to submit the information to government agencies in order to claim incentives.

The acquisition could be a good fit for Power-One, which rose to become the world’s No. 2 inverter maker earlier this year, according to IMS Research report on the second-quarter shipment. The market research firm ranked Power-One at No. 4 in 2009.  Inverters are a must for any solar-panel systems because they convert the electricity from direct current to alternating current for feeding the grid or use on-site. How well inverters perform, then, plays a big role on the overall output of a solar energy field.

The deal also highlights how acquisitions are the favored form of exits for companies in the solar field. Just two weeks ago, solar panel maker Sharp said it would buy San Francisco-based project developer Recurrent Energy for $305 million. In July this year, First Solar bought project developer NextLight Renewable Power for $297 million.

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The company has turned a 1.5 MW wind converter into a new, 600 kW solar inverter for utility projects, Rick Robertson, an inverter program manager at GE, told us at this week’s Solar Power International. The inverter, pictured above, is targeted at multimegawatt solar projects with multiple installations on a single site, he said. GE is now taking orders for the inverter, which was introduced at the conference, and plans to ship its first units by the end of this year, he added.

The inverter is another sign that GE sees solar as “the next wind.” It said last month that it plans to grow its solar production next year, and has also invested in technologies that could make solar cheaper.

To modify the inverter for solar, GE changed the way it connects to power projects, because solar panels generate direct current, which must be turned into the alternating current used by most appliances, whereas wind turbines generate alternating current, said Minesh Shah, a product line leader for renewables systems. GE also modified the software to enable utilities to monitor and control the solar power plants, he added. And the inverter had to be packaged with a new skin suitable for outdoor installations, as wind inverters are usually kept inside the towers, while solar inverters need to be able to survive the elements, said Tony Galbraith, an inverter program manager for GE.

When it comes to the hardware, however, GE says it hasn’t changed much, with the idea being to leverage its experience — and volume — in wind converter manufacturing. The conglomerate already makes 4,000 wind converters annually, and keeping the hardware similar will allow it to simply add new solar volumes on top of that, according to Robertson. GE also believes its reputation and track record with the wind converters will give investors confidence in its solar inverters, as it has 12,000 wind turbines in the field with 175 million operating hours at this point, Robertson said.

One of GE’s main advantages in this space is the company’s understanding of what utilities and power plant operators are looking for, so that it can make solar projects look similar to other power plant interconnections, Shah said. “We know how to turn a 30 MW system from just a collection of panels and modules into a power plant.” The software that comes with the inverter presents information about solar projects in the same way that utilities and power-plant operators are already familiar with viewing power plant data, he said, and it also enables the same level of control to manage the voltage of the electricity output so that it can be smoothly interconnected with the grid.

GE’s move into utility solar is a sign that big companies are starting to see solar as a potentially significant part of the energy mix. But in order to make that happen, the industry needs to start preparing to integrate solar into the grid now, Shah said. “In the solar industry today, people are not thinking about these types of issues,” he said. While other companies are working on smoothing the load from variable renewables, it’s true that the work at the utility level is just beginning.

Jenny Chase, head of solar research for London-based New Energy Finance, said she’s seeing a growing number of companies working on integration. With the world’s largest solar projects underway, “it’s probably quite a good thing that people are thinking about this now,” she said. You can expect to hear more about it soon. Hundreds of megawatts of utility projects are already underway in the U.S., with more announcements expected as utilities work to meet state renewable energy standards.

Graphics courtesy of GE

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While all that’s going on, you can explore the various menus and shortcuts that Navigaya has to chunks of web. These are customizable with your own links too, but the starting set is a good portal to many common sites, categorized into areas like “maps” or “fashion”. Their Category menu gives you browsable news from many sources at once, with headlines and videos as well. All in all, it’s a surprisingly engaging way to explore the web, though I don’t know that I’d try to use it when I wanted to get serious work done.

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CleanBreak isn’t surprised by the possibility of an acquisition, calling Xantrex “a success story that investors didn’t fully appreciate.” The company reported C$62 million in revenue in the first quarter, a 55 percent increase over the same period the year before. Xantrex is scheduled to report its second-quarter results at the end of the month.

Xantrex has recently inked $7.3 million worth of supply agreements. Just last week, it signed a deal to provide its inverters to solar energy provider Sun Edison over the next year that it says is worth some $5 million. Xantrex will also be supplying the mysterious and cash-laden OptiSolar with $1.9 million of inverters for that solar company’s planned 50-megawatt solar farm in Sarnia, Ontario, by the end of year.

The inverter is a weak link in a solar power system. While solar panels can last upwards of 20 years, the lifespan of inverters can hover around 10 years. But Xantrex isn’t alone in going after the power electronics market segment of solar. Enphase Energy raised $6.5 million at the start of the year and last month started selling its solar inverters. 1-Solar, a winner in last year’s California Clean Tech Open, specializes in solar inverters and the CEO and founder Tranh Nguyen told us back in February that he had a $5 million Series A round in the works and a $72 million sales deal lined up with a southern Californian customer.

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To find out how the site has fared since then, we spoke with TV Guide Online general manager Paul Greenberg. He said TVGuide.com has more than doubled its unique visitors, to 6 million per month, with an average of 15 minutes spent on the site.

“We are actually making money on online video,” Greenberg said, though he declined to get any more specific other than to say that all the ad inventory on the site has been sold out since it launched, and it’s already sold out through the end of this year.

Right now TV Guide, which was bought by Macrovision for $2.8 billion last December, hosts and embeds clips and also links to video off-site. The online video guide updates its index with a fresh scrape of the web every hour. This makes a nice service for, say, a Lost blogger, who can bring in an RSS feed of all the fresh Lost-related video. But the experience could be massively improved if the content were available directly on TVGuide.com. The site is “close to entering partnerships with all the networks,” according to Greenberg.

Currently, the site continues to discriminate against user-generated and semi-professional content. “The key is not to clutter up our index with things that only a few people will watch,” said Greenberg. How do you decide what qualifies for your index, we asked — is there a certain popularity threshold? “It’s more of a gut editorial choice,” Greenberg replied.

The last year didn’t exactly go as planned; TV Guide in November canceled its online video awards, citing the writers’ strike. The site ended up announcing its award winners via press release.

What’s next? Community building and “Web 2.0 tools,” according to Greenberg, who said he’ll be outsourcing some of these projects to companies like LiveWorld.

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The Cybook Gen3 is a tad over six ounces with a six inch screen displaying at 166 dpi. Now, I’m starting to think they should have called it "The Six" although I’m certain that some BSG fans would riot. You’ll get about 8,000 page flips per battery charge since the device only uses juice when rendering a new page. Content support is in the form of Mobipocket, which should help give this device a nice boost. Congrats Bookeen and best of luck with the Gen3!

(via Mobile Read)

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