Sometimes a museum exhibition that sounds like a natural turns out to be anything but. That's the odd case with a new show at the Los Angeles County Museum of Art, which juxtaposes five gorgeous paintings by Impressionist icon Claude Monet (1840-1926) with five handsome ones by Pop master Roy Lichtenstein (1923-1997). For all the visual firepower of the individual works, as a show it's strangely flat and uninvolving.
By all means don't miss it — if not for the Lichtensteins, which have been shown at LACMA before (they belong to L.A. collectors Eli and Edythe Broad), then for the Monets. I doubt that five paintings from his pivotal series showing the soaring Gothic facade of Rouen Cathedral have ever been seen at once in Los Angeles before, and these five are fantastic. (The Getty Museum also owns a beautiful example, painted in the silvery light of morning.) They come from major public collections of Impressionist paintings — two from the Museum of Fine Arts, Boston, which co-organized the show with LACMA, and three from Paris' Musée d'Orsay.
The Monet cathedral paintings occupy two walls. On a third wall to the right are Lichtenstein's 1969 cathedral views -- larger, sleeker and painted by hand in small dots, the artist's familiar adaptation of modern commercial printing techniques. Each Lichtenstein is a two-color painting.
Some, such as the ones composed from interlocking red and yellow dots or blue and yellow dots, read as crisp, clear images of the church. Others, like the ones in yellow and white or blue and black, are so close in color values as to require scrutiny to make out the image. The yellow and white allude to blinding sunlight, the blue and black to the dead of night -- extreme daytime and nighttime interruptions in the ordinary practice of seeing.
The five pictures, each more than 5 feet high and 3 1/2 feet wide, are installed close together, side by side. Appropriately, the lineup is almost like sheets rolling off an assembly line or proofs from a printing press. In a media environment, reproduction rather than light creates or obscures the view; Lichtenstein refocuses attention on painting.
The Monets do too, but in a dramatically different way. In the late winter and early spring of 1892 and 1893 he painted about 30 versions, finishing what he started on site in Rouen back in his Giverny studio, closer to Paris. (Rouen is about 80 miles northwest of the capital.) These canvases, often intense, are smaller than the Lichtensteins — no dimension is more than 40 inches — and more chromatically diverse. In painting the effects of light and atmosphere at different times of day and under various weather conditions, Monet's broken brushwork used just about every oil color in the painter's arsenal.
The cathedral facade, seen here at a slight angle from the picture plane, nearly fills the entire composition. Only a small patch of sky is glimpsed at the top between the two front towers. Rouen offered Monet an intricately detailed stone surface, built over six centuries and marked by a seemingly infinite array of nooks, crannies and shadow patterns.
He chose to represent that surface — strong, sturdy, magnificently articulated and inseparable from his nation's long and splendid cultural history — by drawing a direct comparison between the church facade and his own painting's surface. Each work is heavily encrusted with densely layered colors, asserting the artist's lengthy labors in constructing the picture. It swallows up extreme nuances of dramatic visual knowledge gained over time. It represents the spiritual glorification of secular faith.
Monet's Rouen Cathedral paintings transfer the enduring power of epic masonry from religion to art. In their vibrant, light-filled stylistic innovation, they put dynamic change on an equal footing with heroic constancy.
So, given these two major artists, why doesn't the exhibition resonate? Partly it's just a matter of unequal weight. The balance seems out of whack.
The Lichtenstein paintings are very good, but his best works are the comic book and advertising paintings he began in 1961, as well as the reflection-free mirror paintings he started work on at the same time as the "Rouen Cathedral" series. Monet, by contrast, is in peak form here: He made other paintings just as great, but none greater.
Poor Lichtenstein. Monet's voluptuary, arduous surfaces keep drawing you away.
More inexpedient is the show's forced point. Was Lichtenstein putting his work in direct dialogue with Monet's, as is implied here? Not really. Whatever conversation there is between them is only indirect.
Monet's paintings didn't inspire Lichtenstein; photographs did. Monet was responding to the surface realities of light on the facade of Rouen Cathedral; Lichtenstein was responding to the surface realities of mass reproduction. For Lichtenstein the Monet cathedrals, while not entirely incidental, are just a distant background story. They're almost like academic footnotes.
A wall text explains the show's rationale. In 1968, Pasadena Art Museum curator John Coplans organized a famously influential exhibition titled "Serial Imagery." Lichtenstein saw it. He was impressed by artists who, rather than making singular masterpieces, were engaged in exploring paintings and sculptures in series.
Coplans' artists were as diverse as Josef Albers, with his precisely nested color squares, and Morris Louis, who poured rivulets of paint. The curator traced their origins back to Monet, whose "Rouen Cathedral" paintings are offered as a foundational masterstroke of serial imagery.
But are the Monet's really serial images? Critic Brian O'Doherty once noted that Coplans didn't make the necessary distinction between series (paintings on the same theme or subject) and serial (paintings based on systems). Therein lies the essential difference between the cathedral pictures of Monet and Lichtenstein. Monet explored multiple permutations of one theme, while Lichtenstein investigated mass-media systems, jolting life into otherwise deadened reproduction techniques.
Ironically, when I saw the show a work from LACMA's permanent collection happened to be installed in another gallery just around the corner, and it resonates in a more revealing way. In 1971, Andy Warhol silk-screened 100 plain wooden crates to look like corrugated cardboard shipping cartons that contain boxes of Kellogg's Corn Flakes. Warhol was nearing the end of his most innovative period -- the 1973 portraits of Chairman Mao would be his last hurrah -- but the boxes still exploit the sharp visual puns that dominate his great '60s work.
2011年10月18日星期二
2011年8月28日星期日
Cheap returns for clueless Olley art thief
Art tends to skyrocket in value after the artist passes away - or so the cliche goes. It was perhaps with this in mind that a thief walked into the Bowral and District Hospital five days after Margaret Olley's death and took one of her pictures from a wall.
The crime was meticulously planned. The thief walked into the waiting room at the children's ward with a cheap replacement print swathed in white fabric. With the new print disguising the theft, it took hospital staff five days to miss Olley's work.
It might have been the perfect get-rich-quick scheme - but for one crucial detail. While Olley's paintings and signed prints sell for thousands of dollars, the hospital's unsigned reproduction of the oil painting Parrot Tulip is worth next to nothing. Identical prints are on sale at the Mittagong Visitor Information Centre for $50.
Olley painted it to raise money for the McGrath Foundation during the annual Southern Highlands Tulip Time Festival. It sold at auction for $50,000 to the broadcaster Alan Jones, who donated it back to the charity.
Organisations that helped with the fund-raising received unsigned reproductions of Olley's work. One of the 100 prints went to Berrima District Credit Union's charity foundation for children. The credit union spent $400 on framing and donated it to the hospital. The vice president of the credit union foundation, Ross Stone, said the theft was disappointing, though - given the work's value - hardly alarming. ''I don't know what they think they'll do with it,'' Mr Stone said.
The police have identified a suspect. Moss Vale policeman Senior Constable Martyn Rigby said it was ''reasonable'' to speculate the thief hoped to cash in on Olley's death.
''It's a brazen act,'' he said.
The crime was meticulously planned. The thief walked into the waiting room at the children's ward with a cheap replacement print swathed in white fabric. With the new print disguising the theft, it took hospital staff five days to miss Olley's work.
It might have been the perfect get-rich-quick scheme - but for one crucial detail. While Olley's paintings and signed prints sell for thousands of dollars, the hospital's unsigned reproduction of the oil painting Parrot Tulip is worth next to nothing. Identical prints are on sale at the Mittagong Visitor Information Centre for $50.
Olley painted it to raise money for the McGrath Foundation during the annual Southern Highlands Tulip Time Festival. It sold at auction for $50,000 to the broadcaster Alan Jones, who donated it back to the charity.
Organisations that helped with the fund-raising received unsigned reproductions of Olley's work. One of the 100 prints went to Berrima District Credit Union's charity foundation for children. The credit union spent $400 on framing and donated it to the hospital. The vice president of the credit union foundation, Ross Stone, said the theft was disappointing, though - given the work's value - hardly alarming. ''I don't know what they think they'll do with it,'' Mr Stone said.
The police have identified a suspect. Moss Vale policeman Senior Constable Martyn Rigby said it was ''reasonable'' to speculate the thief hoped to cash in on Olley's death.
''It's a brazen act,'' he said.
2011年3月28日星期一
Enphase Launches Solar IT Offensive
Enphase Energy has been creating a market for solar microinverters –distributed inverters that replace a central inverter for solar panels — since its initial product launch in the summer of 2008 and has now shipped more than 500,000 of them.
To keep its lead will not be easy, however. Not only is venture-backed Enphase facing competition from other microinverter developers, but it's also up against companies making alternative and more mainstream products, like the traditional central inverters. To remain competitive, the Petaluma, Calif., startup will be launching a series of products this year that are smaller, lighter and tailored to different customer types.
Enphase Offensive
In June, it plans to launch its third-generation technology that will boost its microinverter's average efficiency to 96 percent, a one percentage point improvement from the current version, Enphase's VP of products, Raghu Belur, told a group of reporters at the company's headquarters Tuesday. The company will also offer a new installation method that will help shave labor costs. Enphase CEO, Paul Nahi, also hinted at the possibility of offering a warranty that will be longer than the 15 years that it current provides.
In addition, the startup, founded in 2006, is working on a microinverter specifically designed for the larger, commercial installations, Nahi said. Until now, the company has offered the same microinverter for both residential and commercial installations. And, by the end of the year, Enphase is looking at rolling out yet another product that will feature three chips, which will reduce the number of components in its microinverter box and improve its efficiency at power conversion, Nahi said.
The three-chip design will be a departure from the use of a single chip, but Nahi was mum about how the three chips will divide up the core functions of power conversion, communication, control and command. He also declined to talk about the likely efficiency of this new design.
Microinverter Market
Inverters are electronic devices that accompany every solar energy system. They convert the direct current from the solar panels into alternating current for use onsite (at home or business) or for feeding into the grid. Microinverters are so named because they are much smaller than the centralized inverters that dominate the market today. A centralized inverter is larger and sits near the edge of a solar energy system and converts all the electricity flowing from the solar panels.
A microinverter, which is roughly the size of a half-piece of paper, is attached to each solar panel instead. It's a design that enables close monitoring of each solar panel's performance and circumvents the tendency of a solar array to drop its power output collectively even if only a few solar panels aren't able to perform optimally because of, say, shading or debris that blocks the sunlight from hitting the cells inside the panels.
“Our microinverters are generating more power than you would with a centralized inverter. That's just physics,” Nahi said.
Enphase executives say they've carved out a market for a type of technology that couldn't take off before Enphase's arrival, primarily because it was too expensive, inefficient, unreliable and lacked communication functions to effectively monitor performance. The company sells not only the microinverter but also software and services for monitoring the power production of each system. Both installers and system owners can check on the performance of each solar panel by logging into an Enphase portal, and the microinverters will alert them of significant drop in power production.
Microinverters have no shortage of critics, who contend that microinverters haven't proven their staying power because they are new to the market. They also argue that installing a bunch of microinverters could lead to frequent repairs and replacement. Microinverter advocates have countered that the failure of a centralized inverter will cripple the production of an entire solar array, whereas problems with a few microinverters will only handicap the performance of those few solar panels.
Future of Microinverters
Microinverters do remain more expensive than central inverters. Enphase executives say their gears are 15 percent more expensive, but they have come up with installation methods to cut labor costs. A new installation method, to be offered with the third-generation microinverter in June, will involve Enphase-provided cables with built-in connectors and clips to pin the cables to the racks underneath the solar panels. A single bolt will secure each microinverter, which will then plug into the connector on one side and solar panel on the other.
So, that 15-percent price premium will be offset by a lower installation cost and the extra 5-25 percent electricity production, Nahi said. This sales pitch could work well for installers who care more about the amount of energy to be produced over time than the upfront installation cost.
The majority of its microinverters have gone to residential systems. Enphase is keen to expand its reach in the commercial sector, where each installation is larger and therefore requires more microinverters. The company plans to launch a microinverter with a higher voltage to target the commercial sector, Nahi said. The largest project to date that uses Enphase's gear has 750KW of generation capacity, Belur said.
Enphase Wins Converts
The company sells its microinverters and services through distributors and solar panel makers such as Suntech Power, Canadian Solar and Siemens. A major installer who until recently wasn't an Enphase convert will use the microinverters as a result of snapping up businesses that were Enphase customers. That installer is SolarCity, based in San Mateo, Calif., which bought Clean Currents Solar and groSolar's residential installation business recently in order to expand its business to the East Coast, said Jake Whiteley, strategic account manager at Enphase.
Although Enphase is the largest microinverter supplier, it's not the only one and will face a growing competition from fellow microinverter developers. Competitors include SolarBridge Technologies in Texas and Enecsys in the United Kingdom. Its central inverter nemeses include SMA Solar Technology and Power-One.
Transphorm, a Google Venture-backed startup, also is eyeing the solar market with its power conversion technology. Instead of using silicon chips, as Enphase does, Transphorm is using gallium nitride. Enphase also is investigating the use of these more exotic materials, Nahi said, but has no plans to roll out products using them any time soon.
To keep its lead will not be easy, however. Not only is venture-backed Enphase facing competition from other microinverter developers, but it's also up against companies making alternative and more mainstream products, like the traditional central inverters. To remain competitive, the Petaluma, Calif., startup will be launching a series of products this year that are smaller, lighter and tailored to different customer types.
Enphase Offensive
In June, it plans to launch its third-generation technology that will boost its microinverter's average efficiency to 96 percent, a one percentage point improvement from the current version, Enphase's VP of products, Raghu Belur, told a group of reporters at the company's headquarters Tuesday. The company will also offer a new installation method that will help shave labor costs. Enphase CEO, Paul Nahi, also hinted at the possibility of offering a warranty that will be longer than the 15 years that it current provides.
In addition, the startup, founded in 2006, is working on a microinverter specifically designed for the larger, commercial installations, Nahi said. Until now, the company has offered the same microinverter for both residential and commercial installations. And, by the end of the year, Enphase is looking at rolling out yet another product that will feature three chips, which will reduce the number of components in its microinverter box and improve its efficiency at power conversion, Nahi said.
The three-chip design will be a departure from the use of a single chip, but Nahi was mum about how the three chips will divide up the core functions of power conversion, communication, control and command. He also declined to talk about the likely efficiency of this new design.
Microinverter Market
Inverters are electronic devices that accompany every solar energy system. They convert the direct current from the solar panels into alternating current for use onsite (at home or business) or for feeding into the grid. Microinverters are so named because they are much smaller than the centralized inverters that dominate the market today. A centralized inverter is larger and sits near the edge of a solar energy system and converts all the electricity flowing from the solar panels.
A microinverter, which is roughly the size of a half-piece of paper, is attached to each solar panel instead. It's a design that enables close monitoring of each solar panel's performance and circumvents the tendency of a solar array to drop its power output collectively even if only a few solar panels aren't able to perform optimally because of, say, shading or debris that blocks the sunlight from hitting the cells inside the panels.
“Our microinverters are generating more power than you would with a centralized inverter. That's just physics,” Nahi said.
Enphase executives say they've carved out a market for a type of technology that couldn't take off before Enphase's arrival, primarily because it was too expensive, inefficient, unreliable and lacked communication functions to effectively monitor performance. The company sells not only the microinverter but also software and services for monitoring the power production of each system. Both installers and system owners can check on the performance of each solar panel by logging into an Enphase portal, and the microinverters will alert them of significant drop in power production.
Microinverters have no shortage of critics, who contend that microinverters haven't proven their staying power because they are new to the market. They also argue that installing a bunch of microinverters could lead to frequent repairs and replacement. Microinverter advocates have countered that the failure of a centralized inverter will cripple the production of an entire solar array, whereas problems with a few microinverters will only handicap the performance of those few solar panels.
Future of Microinverters
Microinverters do remain more expensive than central inverters. Enphase executives say their gears are 15 percent more expensive, but they have come up with installation methods to cut labor costs. A new installation method, to be offered with the third-generation microinverter in June, will involve Enphase-provided cables with built-in connectors and clips to pin the cables to the racks underneath the solar panels. A single bolt will secure each microinverter, which will then plug into the connector on one side and solar panel on the other.
So, that 15-percent price premium will be offset by a lower installation cost and the extra 5-25 percent electricity production, Nahi said. This sales pitch could work well for installers who care more about the amount of energy to be produced over time than the upfront installation cost.
The majority of its microinverters have gone to residential systems. Enphase is keen to expand its reach in the commercial sector, where each installation is larger and therefore requires more microinverters. The company plans to launch a microinverter with a higher voltage to target the commercial sector, Nahi said. The largest project to date that uses Enphase's gear has 750KW of generation capacity, Belur said.
Enphase Wins Converts
The company sells its microinverters and services through distributors and solar panel makers such as Suntech Power, Canadian Solar and Siemens. A major installer who until recently wasn't an Enphase convert will use the microinverters as a result of snapping up businesses that were Enphase customers. That installer is SolarCity, based in San Mateo, Calif., which bought Clean Currents Solar and groSolar's residential installation business recently in order to expand its business to the East Coast, said Jake Whiteley, strategic account manager at Enphase.
Although Enphase is the largest microinverter supplier, it's not the only one and will face a growing competition from fellow microinverter developers. Competitors include SolarBridge Technologies in Texas and Enecsys in the United Kingdom. Its central inverter nemeses include SMA Solar Technology and Power-One.
Transphorm, a Google Venture-backed startup, also is eyeing the solar market with its power conversion technology. Instead of using silicon chips, as Enphase does, Transphorm is using gallium nitride. Enphase also is investigating the use of these more exotic materials, Nahi said, but has no plans to roll out products using them any time soon.
2011年3月22日星期二
National Semiconductor Introduces New SolarMagic ICs for Microinverter, Power Optimizer and Charge Controller Systems
National Semiconductor Corp. (NYSE: NSM) today introduced ten new SolarMagic™ integrated circuits (ICs), the first in a series developed to reduce cost, improve reliability and simplify design of photovoltaic (PV) systems. Ranging from the industry's first full-bridge gate driver to a micropower voltage regulator, the new ICs are well-suited for a variety of photovoltaic electronic applications, including those found in microinverters, power optimizers, charge controllers and panel safety systems.
"National now offers an extensive portfolio of analog and mixed signal ICs that provide manufacturers of microinverters with the robust, renewable energy grade ICs they need to ensure long-term operation," said Bill Mazotti, Solar IC Business Unit Director at National. "National's solutions for the photovoltaic space now include components for power optimizers, microinverters and inverters."
The new SolarMagic ICs are the first developed to meet photovoltaic renewable energy-grade qualification requirements. Each IC is engineered specifically for demanding rooftop environments that range from extreme cold to severe heat, and each passes rigorous testing with enhanced reliability specific to solar requirements. In addition, the ICs ensure long-term operation, developed to meet and exceed the 25-year life expectancy of photovoltaic modules.
Collectively provided as a complete design, SolarMagic ICs increase energy harvest, reduce cost per kilowatt-hour and improve safety in junction boxes and other types of enclosures. Used independently, the ICs provide high voltage and high current gate drive for microinverter or power optimizer designs.
"National now offers an extensive portfolio of analog and mixed signal ICs that provide manufacturers of microinverters with the robust, renewable energy grade ICs they need to ensure long-term operation," said Bill Mazotti, Solar IC Business Unit Director at National. "National's solutions for the photovoltaic space now include components for power optimizers, microinverters and inverters."
The new SolarMagic ICs are the first developed to meet photovoltaic renewable energy-grade qualification requirements. Each IC is engineered specifically for demanding rooftop environments that range from extreme cold to severe heat, and each passes rigorous testing with enhanced reliability specific to solar requirements. In addition, the ICs ensure long-term operation, developed to meet and exceed the 25-year life expectancy of photovoltaic modules.
Collectively provided as a complete design, SolarMagic ICs increase energy harvest, reduce cost per kilowatt-hour and improve safety in junction boxes and other types of enclosures. Used independently, the ICs provide high voltage and high current gate drive for microinverter or power optimizer designs.
2011年3月20日星期日
Solar Summit 2011: The Inverter War
In most businesses, competitors tend to soften their comments about one another.
That's the not the case in inverters and solar electronics.
"I don't get it," said Raghu Belur, co-founder of microinverter maker Enphase Energy, when
asked about companies that want to popularize DC maximizers for improving how centralized
inverters work during an interview at the Solar Industry Summit this week. "I simply don't
get it."
Companies that specialize in central inverters like SMA and microinverter specialists like
SolarBridge and Enphase are locked in a battle over the future of solar electronics.
Microinverter champions say that their technology works better and costs less in any type of
solar installation of any size, anywhere in the world.
Enphase has a pending third-generation product, for instance, that achieves efficiencies in
the 96-percent-plus range and will be capable of being installed at utility-scale sites. The
company is also looking at advanced AC-DC materials like gallium nitride, a material promoted
by Transphorm, and more silicon carbine.
In a few years, a microinverter could consist of three components and need very little copper
and other raw materials, Belur speculated. This will allow the industry to ride the Moore's
Law cost curve down. Dick Swanson, the keynote speaker at the event, said that the SunShot
program sponsored by the Department of Energy seeks to get solar down to $1 a watt installed:
in that scenario, only ten cents could be allocated to inverters.
Centralized inverter advocates, meanwhile, argue that they too are driving down costs and
looking at advanced materials. Some of the efficiencies obtained through microinverters with
things like DC maximizers. Most centralized inverter makers (including SMA) have actually
laid plans to make microinverters, but they generally believe that microinverters will
largely be confined to the residential market.
More importantly, central inverter advocates say that microinverters create risk. Instead of
having a centralized box, microinverters force solar installers to put 20 to 30 times the
number of devices into the field, which means more potential points of failure.
"If reliability is compromised, it will hurt the entire industry," said Jurgen Krenkhe,
president and general manager of SMA America.
Ken Christensen of central inverter maker Advanced Energy added that central inverters hit
efficiencies in the 97-percent-plus range.
Luckily, as interviews and panel discussions proved, the two sides aren't afraid to air their
differences.
"There is this idea that centralized inverters are more reliable, but the data doesn't
support that," said John Berdner, general manager of North America for SolarEdge during a
panel discussion. "This idea is simply not true."
Berdner cited a study from SunEdison that showed that central inverters exhibited a
reliability of under 50 percent, while string and microinverters were 95 percent reliable.
Part of the problem stems from how these products are made. Microinverters are produced on
manufacturing lines, while centralized inverters are largely hand-assembled.
"Reliability" in the study referred to the number of times a service call was made and did
not necessarily account for every actual breakdown. And speaking of data, Krenkhe added that
microinverters have only been in volume production for about two years.
"To look at six, nine or twelve months of data is a snapshot," he said.
That comment prompted Barry Cinnamon, CEO of Westinghouse Solar, to pop open his laptop and
show me data. (Cinnamon wasn't on the panel. He just happened to be sitting next to me in the
audience.)
Over a two-year period, Westinghouse/Akeena Solar installed 10,630 microinverters, of which
22 had to be replaced. The company also installed 3,373 centralized inverters; 318 had to be
repaired. The microinverter-powered systems lost 528 hours of power production. The central
inverter systems lost 464,000 hours. (Side note: Cinnamon noted at SMA had the far lowest
failure rate.)
The disparity in hours of power production lost comes because in a centralized inverter
system, the entire solar array goes down if the inverter does. In a microinverter system,
only individual panels are temporarily off-line.
In response, Jeff Krisa, vice president of sales and marketing at Tigo Energy, which makes DC
maximizers that link to centralized inverters, noted that a lot of residential installers
like microinverters. DC maximizers are just beginning to be introduced.
Who's right? The data over the next few years will tell the tale. Microinverters are
definitely gaining ground -- Enphase claims a 13 percent market share in recent California
residential installations. The company also gives a 15-year warranty and claims its
microinverters will last far longer. Still, the products are only a few years old and the
solar industry is notoriously conservative.
That's the not the case in inverters and solar electronics.
"I don't get it," said Raghu Belur, co-founder of microinverter maker Enphase Energy, when
asked about companies that want to popularize DC maximizers for improving how centralized
inverters work during an interview at the Solar Industry Summit this week. "I simply don't
get it."
Companies that specialize in central inverters like SMA and microinverter specialists like
SolarBridge and Enphase are locked in a battle over the future of solar electronics.
Microinverter champions say that their technology works better and costs less in any type of
solar installation of any size, anywhere in the world.
Enphase has a pending third-generation product, for instance, that achieves efficiencies in
the 96-percent-plus range and will be capable of being installed at utility-scale sites. The
company is also looking at advanced AC-DC materials like gallium nitride, a material promoted
by Transphorm, and more silicon carbine.
In a few years, a microinverter could consist of three components and need very little copper
and other raw materials, Belur speculated. This will allow the industry to ride the Moore's
Law cost curve down. Dick Swanson, the keynote speaker at the event, said that the SunShot
program sponsored by the Department of Energy seeks to get solar down to $1 a watt installed:
in that scenario, only ten cents could be allocated to inverters.
Centralized inverter advocates, meanwhile, argue that they too are driving down costs and
looking at advanced materials. Some of the efficiencies obtained through microinverters with
things like DC maximizers. Most centralized inverter makers (including SMA) have actually
laid plans to make microinverters, but they generally believe that microinverters will
largely be confined to the residential market.
More importantly, central inverter advocates say that microinverters create risk. Instead of
having a centralized box, microinverters force solar installers to put 20 to 30 times the
number of devices into the field, which means more potential points of failure.
"If reliability is compromised, it will hurt the entire industry," said Jurgen Krenkhe,
president and general manager of SMA America.
Ken Christensen of central inverter maker Advanced Energy added that central inverters hit
efficiencies in the 97-percent-plus range.
Luckily, as interviews and panel discussions proved, the two sides aren't afraid to air their
differences.
"There is this idea that centralized inverters are more reliable, but the data doesn't
support that," said John Berdner, general manager of North America for SolarEdge during a
panel discussion. "This idea is simply not true."
Berdner cited a study from SunEdison that showed that central inverters exhibited a
reliability of under 50 percent, while string and microinverters were 95 percent reliable.
Part of the problem stems from how these products are made. Microinverters are produced on
manufacturing lines, while centralized inverters are largely hand-assembled.
"Reliability" in the study referred to the number of times a service call was made and did
not necessarily account for every actual breakdown. And speaking of data, Krenkhe added that
microinverters have only been in volume production for about two years.
"To look at six, nine or twelve months of data is a snapshot," he said.
That comment prompted Barry Cinnamon, CEO of Westinghouse Solar, to pop open his laptop and
show me data. (Cinnamon wasn't on the panel. He just happened to be sitting next to me in the
audience.)
Over a two-year period, Westinghouse/Akeena Solar installed 10,630 microinverters, of which
22 had to be replaced. The company also installed 3,373 centralized inverters; 318 had to be
repaired. The microinverter-powered systems lost 528 hours of power production. The central
inverter systems lost 464,000 hours. (Side note: Cinnamon noted at SMA had the far lowest
failure rate.)
The disparity in hours of power production lost comes because in a centralized inverter
system, the entire solar array goes down if the inverter does. In a microinverter system,
only individual panels are temporarily off-line.
In response, Jeff Krisa, vice president of sales and marketing at Tigo Energy, which makes DC
maximizers that link to centralized inverters, noted that a lot of residential installers
like microinverters. DC maximizers are just beginning to be introduced.
Who's right? The data over the next few years will tell the tale. Microinverters are
definitely gaining ground -- Enphase claims a 13 percent market share in recent California
residential installations. The company also gives a 15-year warranty and claims its
microinverters will last far longer. Still, the products are only a few years old and the
solar industry is notoriously conservative.
订阅：
博文 (Atom)