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Sunday, April 29, 2012

Soraa unveils GaN-on-GaN LEDs and MR16 lamps


Silicon Valley start-up Soraa is manufacturing LEDs using a unique GaN-on-GaN process, and has used these to build high-performance MR16 lamps that are its first products.
Soraa, a stealthy start-up company based in Fremont, California, made its first public appearance at last week’s Strategies in Light conference via a presentation from CEO Eric Kim, a booth in the exhibition, and a press release announcing the company’s first products, which are LED-based MR16 lamps.
Soraa MR16 LED lamp
LED industry insiders were not surprised by the appearance of Soraa; after all, it’s quite hard to assemble a team of high-profile engineers, receive funding from Khosla Ventures and build an LED fab in Fremont without attracting attention. The company was founded by three UCSB professors – Steve DenBaars, Jim Speck, and Shuji Nakamura – who have been joined by key personnel from Philips Lumileds and elsewhere. Kim, a former senior Intel executive, was announced as Soraa CEO in June 2010.


Nakamura made a huge contribution to the development of the LED industry during his time at Nichia in the 1990s. More recently, he is known to have worked extensively on growing gallium nitride (GaN) material on GaN substrates. So, most observers expected Soraa to announce its first GaN-on-GaN LEDs. Instead, Soraa has incorporated those LEDs into MR16 lamps.
LEDs Magazine asked Kim about this business model. He explained that Soraa currently has a small production volume of LEDs, and feels that MR16 lamps is the best way to maximize revenue and profits at the present time. He also said that an LED replacement for a 50W halogen MR16 lamp “has been the most difficult LED lamp to do correctly, given its small size and intense, high-quality brightness requirements.” So the lamp can act as a demonstration of the performance capabilities of the GaN-on-GaN LED around which it is built.


Soraa GaN-on-GaN LED chip
Although Kim would not reveal pricing for the MR16 lamp, which available to commercial but not retail customers, the company’s press release said the product “is priced to achieve less than one-year payback.”


GaN on GaN
Most GaN-based LEDs are grown by epitaxy on top of sapphire substrates. Cree is notable for using silicon-carbide substrates, while others such as Osram and Bridgelux have made progress in using silicon for its low-cost potential.


Epitaxy is the growth of high-quality crystalline material, and it’s generally best to use the same material for the substrate, so that the crystal structure and thermal-expansion properties of the epitaxial layers match those of the substrate. However, this assumes the substrate material can be obtained with a large diameter and at reasonable (preferably low) cost. This has always been a problem for GaN, and explains why the LED industry mainly uses sapphire.



Kim wouldn’t reveal details of the GaN wafers, but it’s safe to assume they are significantly smaller and much more expensive to purchase than the sapphire used by other LED makers.


Relative droop
But GaN-on-GaN growth provides some big advantages. The LED material has up to a 1000-fold reduction in dislocation density compared with layers grown on sapphire, said Kim. This means that the GaN-on-GaN LEDs can be operated at a much higher current density (around 250 A/cm2) than other LEDs: GaN-on-sapphire LEDs typically operate up to around 100 A/cm2. Above this level, the LEDs are hampered by droop i.e. the fall-off in efficiency with high current density. According to Kim, the GaN-on-GaN LEDs suffer less droop (relative to initial efficiency) even when operated at 250 A/cm2. Driving the LEDs harder produces more light from a smaller area. The spec sheets for Soraa’s lamps says that “Soraa’s unique LED technology allows its lamps to operate effectively and efficiently at higher temperatures than other LED lamps, resulting in more light output per diode.”


But the innovation doesn’t stop there. Soraa is using triangular chips to greatly enhance the extraction efficiency of the light. The chip has a surface area which is many times larger than the area of the LED junction. Because the substrate is GaN it doesn’t absorb the emitted light and doesn’t need to be removed from the chip, as is commonly seen with many thin-film processes.


The GaN-on-GaN LEDs emit in the purple part of the spectrum, likely to be around 400-405 nm (not confirmed by Soraa). The company has combined the LEDs with a three-phosphor mix. It says this provides a complete spectrum, avoiding both the “blue overshoot” and the “cyan gap” seen with conventional blue LEDs and phosphors.


MR16 lamp performance
Soraa’s Premium series (2700K and 3000K) MR16 lamps operate at 12W and are described as having 50W-halogen equivalent performance. The 3000K Premium lamp has a center-beam candle power (CBCP) of 2375 cd. The Essential series provide 40W equivalence from 10W input. All operate from 12 Vac, have a beam angle of 25 degrees, and a lifetime of 25,000 hours (with a 3-year warranty).


As also mentioned in one of the comments below, the lumen output of the lamp is around 350 lm (calculating this from CBCP and beam angle is not straightforward). At SIL, Kim was asked about the efficacy of the lamp and rightly said that this is not a figure usually quoted for directional lamps. However, 350 lm at 12W gives an efficacy of around 29 lm/W for the lamp. This gives some indication of where the performance of Soraa's LEDs sits relative to more conventional devices.

Tuesday, April 24, 2012

Marvell headlines LED driver IC exhibits at SIL


Marvell introduced what it calls a deep-dimming SSL driver IC at Strategies in Light while Texas Instruments, NXP, iWatt, On Semiconductor, STMicroelectronics, and Monolithic Power Systems all demonstrated recently-launched LED driver ICs.


Dimming LEDs remained a hot topic at the just-concluded Strategies in Light (SIL) conference in Santa Clara, CA, and Marvell led the way with the new 88EM8183 single-stage, solid-state lighting (SSL) driver IC that the company says can be smoothly dimmed to 1% of drive current. Designed for retrofit-lamp applications, the new IC relies on a digital signal processing (DSP) core to detect and adapt to different phase-cut dimmers.


The iWatt exhibit also stressed dimming while NXP focused on smart lighting and On Semiconductor had an innovative automotive-centric demonstration. Texas Instruments (TI) hosted dimming demonstrations and highlighted its LM3466 linear driver IC designed for current matching with multiple LED strings. Other companies with IC demos included STMicroelectronics and Monolithic Power Systems.


Marvell 88EM8183
Marvell's new IC can deliver 90% efficiency and a power factor above 0.95. Moreover the IC relies on a primary-side, current-control scheme that reduces the number of external components required in a design. For example, the design eliminates the need for an opto-coupler and other components that comprise the feedback circuit in secondary-side control.
Marvell's 88EM8183 LED driver IC
According to Lance Zheng, Marvell senior manager of technical marketing, the IC can result in a 20-50% reduction in external components compared with competitive ICs. Zheng showed driver circuit boards from some widely available retrofit lamps, one of which was easily recognizable as a Philips design, and the difference in component count relative to Marvell's reference design was clearly noticeable.


Still, dimming remained the main focus of the announcement. Indeed Marvell enlisted lighting-controls-specialist Lutron to demonstrate the extent of the dimming support.
"A major complaint we receive from retailers regarding the transition from incandescent to LED lighting solutions is consumer dissatisfaction with high-performance dimming capabilities in retrofitted bulbs," said Ed Blair, vice president and general manager of Lutron. "For excellent dimming performance, and a great customer experience, we recommend the use of the Lutron C•L dimmer family, which has shown good performance with Marvell’s 88EM8183 solution. While finished designs still need to be tested against applicable safety and performance criteria, LED lighting products which use the 88EM8183 driver chip should yield excellent dimming performance on approved Lutron controls."


Marvell said it has tested the dimming capability with more than 100 Triac phase-cut dimmers. And rather than trying to design a circuit that can adapt blindly to any such a dimmer, the IC designers use the DSP core to detect the specific dimmer on a circuit based on a table of dimmer characteristics collected via its testing program. If the IC can recognize the dimmer, flawless operation is guaranteed although the design can also operate with many untested dimmers.


Marvell's exhibit included a box equipped with a dozen or so dimmers. The demo offered visitors a chance to experience the dimming operation of the new IC with each dimmer.


iWatt's approach to dimming
Of course Marvell's approach to recognizing a dimmer isn't unique. Indeed iWatt relies on the same idea, although the actual implementation is quite different.
Rather than using a processor core and memory, iWatt uses a digital-state machine to detect the dimmer type and adapt for smooth operation. The company says it has also tested more than 100 dimmers.


At SIL, iWatt demonstrated the iW3614 IC that is based on two-stage power converter. The first stage is a boost converter that handles power factor correction, and supports power factor as high as 0.94. A pulse width modulation (PWM) stage minimizes ripple current and eliminates flicker even with smaller output capacitors according to iWatt.



The LM3466 controls multiple LED strings

The two-stage approach does require more external components than do one-stage designs. But Scott Brown, vice president of marketing at iWatt, said that its design eliminates flicker problems that are associated with many one-stage driver ICs. Brown cited the IEEE PAR1789 working group that is currently studying the health impact of low-frequency flicker as a concern for all lamp designers. We will be covering the work of the group in more detail in an upcoming article.


Texas Instruments' driver ICs
TI has what's probably the broadest selection of LED driver ICs in the industry – in part due to recently completed acquisition of National Semiconductor. At SIL, the company had demonstrations of its two most recent LED driver IC announcements – the LM3448 (National Semiconductor heritage) and the TPS92070 (TI heritage).
The LM3448 demonstration focused on dimmer compatibility, while the TPS92070 demonstration focused on the current accuracy at given dim levels. The video embedded below was made at SIL and includes an explanation of each demo.

TI marketing manager Dan Slupik also touted the benefits of the previously mentioned LM3466 IC. The IC is based on a linear architecture and is designed for multi-string applications such as street lights where a single AC/DC converter can supply power to multiple LM3466 ICs – each supplying constant current to an LED string.


Slupik pointed out that the ICs can be connected to one another to ensure that the output current of each IC is identical. The concept allows a luminaire design to recover from a failed string. For example consider a five string design with a conservative drive current specification. Were one string to fail open, the remaining converters could automatically increase the drive current to the remaining strings, thereby boosting light output to accommodate the missing string.


Smart lighting and automotive
NXP demonstrated its smart-lighting technology that is based on the IPv6 over Low power Wireless Personal Area Network (6LoWPAN) protocol. We covered that technology in detail in the most recent issue of LEDs Magazine in an article on lighting controls.
NXP also demonstrated its new SSL2108X driver IC family that targets non-dimmable retrofit lamps. The company says that the ICs can deliver 95% efficiency and require as few as 14 discrete components.


In the automotive area, we've seen broad adoption of LEDs in both head and tail lights – just consider the much-discussed LED-centric Audi Super Bowl ad. But many prognosticators expect LEDs to find broad use for ambient in-car lighting. On Semiconductor demonstrated a model of an auto with trios of red, green, and blue LEDs located at three different locations in the cabin. Drivers would presumably select ambient light colors based on their moods.


Other recent driver news
There have been a number of other recent LED driver IC announcements that you may find interesting as well, that span a breadth of application segments. Again in the automotive segment, Diodes Inc. introduced the ZXLD1371 driver IC that can power 20 LEDs using a choice of buck, boost, or buck-boost control topologies. Supertex announced the HV9989 three-channel IC for backlight applications. The IC can be used with RGB LEDs or to control multiple strings of white LEDs.


Power Integrations just announced a pair of new driver IC reference designs. The DER-286 reference design documents a 30W fluorescent tube LED retrofit that is based on the company's LNK419EG driver IC. Meanwhile the DER-314 focuses on dimmable PAR30/38 LED retrofit lamps.

Bridgelux announces $25 million in new funding and LED street-light installation


LED manufacturer Bridgelux has announced a $25 million investment from Kaistar Lighting, and an SSL project in Tulsa, Oklahoma, that uses luminaires from Amerlux.


Bridgelux has raised an additional $25 million dollars in investment capital to further its development and manufacturing of LEDs for general-illumination applications, with the new funding coming from Xiamen, China-based Kaistar Lighting. The company also announced a new Tulsa, Oklahoma SSL street- and area-lighting project that it has undertaken in partnership with Amerlux.

New Bridgelux investor Kaistar Lighting is a joint venture of Epistar Corp. and Shenzhen Kaifa Technology Co. Bridgelux said it will use the funds to further accelerate its R&D efforts.
"This investment marks the beginning of our cooperation with Kaistar to lead the transition to solid-state lighting," said Bridgelux CEO Bill Watkins. "Kaistar’s cost-competitive manufacturing capabilities combined with Bridgelux’s high-performance packaging solutions will continue to drive down the cost of solid-state technology for general lighting, helping to more rapidly expand the market for LED."


The statement in the above paragraph certainly implies a partnership between Bridgelux and Kaistar. Partnering with a Chinese lighting maker could certainly provide an avenue for success to Bridgelux in supplying LEDs into the Chinese market. Moreover, a manufacturing partner with low-cost and high-volume skills could also benefit Bridgelux in terms of supplying its LEDs into the global market.



The Kaistar investment comes on the heels of two significant investments that the company announced last year. First, Craton Equity Partners announced a $60 million investment in August, and then existing investors added $15 million in funding in October. Bridgelux is using the funds to optimize a gallium-nitride-on-silicon (GaN-on-Si) manufacturing process that it believes can lower LED costs.


Tulsa street lights
Meanwhile Bridgelux is finding success with its existing family of sapphire-based packaged LEDs and arrays including the ES series that is used in the Amerlux D142 and D154 decorative street lights.



DOE Consortium introduces financial tool for LED street lights


The US DOE has released a financial analysis tool that allows municipalities and utilities to calculate the cost of a retrofit LED-based street light installation including rebates, loan costs, energy savings and return on investment.
The US Department of Energy’s (DOE) Municipal Solid-State Street Lighting Consortium has released an economic cost-benefit analysis tool designed to help cities, utilities, and other organizations estimate the cost and impact of switching to LED-based street lighting.
Called the Retrofit Financial Analysis Tool, the Excel-based tool was developed in collaboration with the Clinton Climate Initiative and is available for download at www.ssl.energy.gov/financial-tool.html.


Using the spreadsheet, users can input data for their particular application – such as the incumbent technology, quantities, phase-in period, prevailing electricity and labor rates, sales tax, installation cost, loan interest rate, and rebates – and receive a detailed analysis that includes annualized energy-cost savings, maintenance savings, greenhouse gas reductions and simple payback period.


This information is useful not only for planning, budgeting and applying for financing. The DOE estimates that the cost of LED street lighting has dropped more than 25 percent in the past year, so it is important to have a tool that calculates savings in today’s currency.
The DOE has also estimated that 26.5 million streetlights in the US consume as much electricity each year as 1.9 million households, and generate greenhouse gas emissions equivalent to that produced by 2.6 million cars.


“Converting our nation’s streetlights to LED technology not only could reduce our energy consumption significantly, but also improve the quality of illumination,” said consortium director Edward Smalley of Seattle City Light. “The Retrofit Financial Analysis Tool will make it easier for cities, utilities and others to analyze the cost benefit of LED street lighting, by providing specific key information on costs and return on investment.”


The tool is based on one that the Clinton Climate Initiative developed for analyzing cities such as New York, Los Angeles, Mumbai, and Beijing. The original tool required someone from the climate initiative to run it, due to its complexity. The consortium teamed with the climate initiative to develop a simplified, more user-friendly version that cities could use independently. The tool can be used by municipalities and utilities, whether they purchase and install their own streetlights or contract out the work. The tool includes an instructional video and sample analysis.


The financial tool complements the Model Specification for LED Roadway Luminaires that was published by the consortium in October.

SIL 2012: Market updates, national developments, automotive, backlights


The HB-LED Market track of Strategies in Light opened today with a variety of talks that included a comprehensive market update; news from China, Korea and Europe; a company emerging from stealth mode; and detailed focus on phosphors, displays and automotive headlights.


Ella Shum of Strategies Unlimited opened the event with a more in-depth review of the HB-LED market numbers presented yesterday. She explained that some of the downturn in the LED TV-backlighting market is due to new designs entering the market, especially low-cost, direct backlighting schemes. These designs, which result in thicker panels (so-called “chubby” TVs) compared with slim edge-lit designs, actually use a smaller number of LEDs.


Ling Wu, general secretary of the China Solid-State Lighting Alliance (CSA), spoke about the continued development and expansion of China’s SSL industry, which she said had revenues of RMB 156 billion ($24.8 billion) in 2011. This split into RMB 6.5 billion for epitaxial wafers and chips, 28.5 billion for packaged LEDs, and RMB 121 billion. The Chinese industry is maturing rapidly, and there is plenty of work to build a portfolio of standards, improve the intellectual-property situation, and stimulate international cooperation.


Chung Hoon Lee, the CEO of Korea-based LED maker Seoul Semiconductor, spoke about the factors that have seen three of the country’s LED makers in the top-five suppliers’ list for 2011. “This was driven by backlighting unit (BLU) demand, local infrastructure and geopolitical issues,” he said. Now these companies must react rapidly, targeting the lighting market. Seoul already has a much larger proportion of its revenue from the lighting market, said Lee. He also discussed Ariche, the company’s AC-LED product, saying that this could allow LED- lamp makers to eliminate a lot of the “junk” inside the lamp needed to drive the LED (particularly the AC-DC converter).


Soraa, a stealthy start-up, chose Strategies in Light to make a first public appearance. Eric Kim explained the company’s first product is an MR16 LED lamp designed to replace a 50W halogen. However, the company’s core innovation is to develop GaN-on-GaN LEDs. Because the LED material has a 1000-fold reduction in dislocation density, the LEDs can be driven much harder (250 A/cm2) than traditional LEDs, while suffering much less droop (the drop-off in efficiency at higher current densities). There are a whole range of ways in which the GaN-on-GaN LEDs are different from more conventional devices, not least the triangular chips (see photo). But a number of observers were sceptical due to the high cost of the GaN starting material. Look for a more detailed review of Soraa’s technology and products in LEDs Magazine in the near future.


Phosphors
A session on phosphors included a presentation by Seth Coe-Sullivan of QD Vision, on quantum-dot technology. While presenting results showing significant improvements in reliability, in terms of flux and temperature tolerances, Coe-Sullivan acknowledged that quantum dots for down-conversion of LEDs can only be used in a remote configuration. On-chip coating of the LED would result in a temperature and flux that was far too high.


Rene Wegh further discussed remote-phosphor configurations, stating that the main benefit is enhanced system efficacy. For warm-white LEDs at 2700K, the benefit can easily amount to a 30% enhancement. Also, the LEDs are not affected by the heat energy generated within the phosphor as downconversion takes place, so they remain cooler, and can be driven harder. Philips has made extensive use of remote phosphors in its LED lamps and also its Fortimo modules. Wegh said that quantum dots and organic dyes were good candidates as alternative phosphor materials, but that lifetime was an issue in both cases.


Automotive and Displays
Dirk Vanderhaeghen of Philips Lumileds spoke about the use of LEDs in automotive headlights, and predicted that 2013 would see the first headlights requiring a single LED module per headlight. This, he said, would reduce both cost and system complexity and open the way for penetration of LED headlights in mainstream, rather than just high-end, vehicles. He predicted that the number of cars with LED headlights would grow from 1.5 million in 2013 to 5 million in 2015, and the value of the LED components used in this application would grow from $130 million to $300 million.


Paul Semenza of DisplaySearch continued the discussion on backlights, and said that while this represents the biggest demand for LED chips currently, it would be overtaken by lighting in 2014. He also said that the cost structure for displays is less dependent on the LED cost than is the case for lighting. LEDs represent about 25% of the cost of an LED-backlit TV (obviously this varies by TV size and the backlight design), but around 5% of the whole TV cost. Semenza said that new designs have reduced the number of LEDs per backlight unit (BLU), but the price declines seen recently in the industry have made this less imperative.

Sunday, April 22, 2012

LED lighting experienced strong growth surge in 2011


Strategies Unlimited has reported 69% year-on-year growth in total sales of LED lamps and luminaires, and expects further growth in the next few years for LED lighting products and LED components for lighting.


Despite a decline in the overall market for lighting products in 2011, the LED lighting market (including both LED lamps and LED luminaires) had an exceptionally good year in 2011, growing by 69% year-on-year.
Vrinda Bhandarkar, Director of Research for LED Lighting with market-research firm Strategies Unlimited, said that the total revenue from the LED lighting market was $5.5 billion in 2010 and $9.4 billion in 2011.


The results were presented during the Solid State Lighting Investor Forum at Strategies in Light 2012, which opened today.
Moreover, the LED lighting market is predicted to grow at a compound annual growth rate (CAGR) of 20% from 2011 to 2016.


Commercial and industrial lighting was the biggest growth sector. Bhandarkar said that almost 23 million LED-based downlights were sold worldwide during 2011.
Compared with previous forecasts, the growth in sales of LED lamps has been scaled back, since the products are still expensive and alternatives are available.


However, sales of LED luminaires of many types were higher than previously expected. Bhandarkar said that users are beginning to appreciate the benefits of LED lighting, beyond light output. “LEDs allow you to think about quality of light and control, not just quantity of light,” she said.
LED components for lighting
The total market for LED packages used in lighting applications reached $1.8 billion in 2011, up from $1.2 billion in 2010, according to Ella Shum, Director of LED Research with Strategies Unlimited.


LED components market
This sector of the LED market is expected to grow at a CAGR of 13% from 2011 to 2016, when it will reach $3.3 billion.
The revenue growth for LED components (13%) is less than for LED lighting products (20%) because the average number of LEDs per lamp or luminaire will decrease, and LED pricing will continue to fall.


The growth in LEDs for the lighting sector will help to offset the decline in LED revenue from backlighting (which includes LED backlights for TVs and monitors) and mobile sectors (the latter includes notebooks and tablets).
Overall, said Shum, the total market for packaged LEDs will grow from $12.5 billion in 2011 to $13.3 billion in 2012. It will stay roughly flat in 2013 and then decline slowly (see chart). The overall CAGR from 2011 to 2016 is forecasted to be -0.2%.

Cree announces 3.45-mm LEDs, hits hot 148 lm/W for cool white


The Cree XT-E LED matches the widely-used XP-E LED in footprint and price while offering double the efficacy based on the company's newest silicon-carbide manufacturing platform.
Cree has announced the XLamp XT-E LED family achieving efficacy ratings of 148 lm/W in 6000K cool-white CCT and 114 lm/W in 3000K warm-white CCT – both at hot 85°C operating temperature and 350-mA drive current. The new 3.45x3.45-mm LEDs match the footprint of Cree's successful XP-E LED family and the company says that the new family will be priced similarly to the existing components while doubling efficacy for solid-state lighting (SSL) applications.


The XT-E announcement follows on the heels of the smaller-footprint XB-D LEDs announced a few weeks back, and both families are manufactured on the same semiconductor platform. Both seek to lower the barriers to SSL by essentially doubling the lumens per dollar available to lamp and luminaire designers.


About the XT-E, Cree product marketing manager Paul Scheidt said, "It's an affordable price point for the LED. And you get the highest performance and highest efficacy on the market."
Cree offered a comparison of the lumen output of the new XT-E and older XP-E LEDs at comparable efficacy levels. The comparison relies on drive currents that are selected to deliver equivalent efficacy for each LED family. At 100 lm/W, the XT-E delivers more than 300 lm while the XP-E delivers 100 lm – a greater than 3x advantage. Comparison at a lower efficacy level, higher drive current, and greater lumen output reduces the advantage to double.


Energy Star qualification
There are numerous advantages to the fact that the XT-E is a successor to the XP-E family. For example, the LEDs can be easily designed into existing products. Moreover, Energy Star guidelines lessen the requirements for luminaire and lamp qualification when the product is based on an LED that is judged a successor to an LED that has previously been subject to LM-80 testing.


Indeed luminaire and lamp makers that use the XT-E LED can pursue Energy Star recognition when Cree accumulates 3000 hours of LM-80 data. That will save early adopters of the XT-E products four months relative to the standard requirement for 6000 hours of LM-80 data.
Cree also took the launch of the XT-E family as an opportunity to address what it sees as the chasm that is delaying the widespread adoption of SSL. Ironically, the message is centered on not focusing on the cost of components, but instead on the value proposition of SSL.
Cree's Scheidt said, "Some people think that light at any cost is the path across the chasm," and he was referring to companies focused on the lowest priced LEDs in making the comment. Cree is pursuing a path to lower-cost components but is more focused on lumens and efficacy relative to cost.


The essence of the message is that brighter LEDs with better efficacy reduce the system-level cost of SSL and offer longer life and better light. Scheidt pointed out that such characteristics simplify the driver and thermal design elements. Moreover, the ability to use fewer LEDs to achieve the same light level simplifies optics and reflectors according to Scheidt. Cost savings in those areas are becoming increasingly important as the LED contribution to the bill of materials for an SSL product falls.


The message is apparently resonating with Cree customers. "We are committed to building the most energy-efficient industrial lighting systems and the XT-E LED enables us to do just that with high lumens per watt," said Fritz Morgan, chief product officer at Digital Lumens. "The result is an intelligent LED-based lighting system that is driving widespread adoption of LEDs in industrial facilities, with compelling performance and end-user payback."


XT-E product details
The XT-E family spans a CCT range from 2700K to 10,000K. In the 5000K to 10,000K cool-white products, Cree has added a minimum 70 CRI option that it hasn’t previously offered in that range. Such cool-white LEDs are primarily targeted at outdoor lighting where color rendering is often considered less important. Scheidt said that some European agencies as well as the Design Lights Consortium are increasingly requiring a minimum CRI and that drove the decision to offer a CRI minimum in cool white.


Neutral-white LEDs in the 3500K-5000K CCT range feature a typical 75 CRI and can be specified with a minimum of 70 or 80 CRI. Warm-white LEDs in the 2700K-3500K range feature a typical 80 CRI and can be specified with a minimum 70 or 80 CRI.
All of the XT-E LEDs can be driven at a maximum of 1500 mA. And all, including cool-white LEDs, are hot binned at a 85°C junction temperature and at a 350-mA drive current.
At 25°C operating temperature, efficacy tops out at 162 lm/W. In cool white, the LEDs produce 139 lm at 85°C and 159 lm at 25°C, both at 350-mA drive currents.

Saturday, April 21, 2012

Audi’s LED headlights are key feature in Super Bowl ad


Audi has released its advertisement that will run during Sunday’s Super Bowl game. It highlights the company’s distinct LED headlights.


Audi has released its latest advertisement that demonstrates the distinct LED headlight design used on its automobiles. The ad will air during the first quarter of the Super Bowl football game this Sunday.
The video shows an outdoor party of teen vampires and a fellow vampire who attempts to join the party as he drives up in the new Audi S7, only to have the LED headlights, which mimic daylight, zap the party-goers into thin air.
"In the spot, Audi LEDs – which at 5500 Kelvin produce the closest recreation of daylight available – put an end to the vampire party, and perhaps, to the greater vampire trend in pop culture," said Scott Keogh, chief marketing officer of Audi of America.


Keogh added, "Given the power of the Super Bowl platform, we wanted to create an entertaining spot that clearly focused on our LED headlights - one of our key product attributes - while also sparking conversation about whether or not it's time for us to move on from the omnipresent vampire trend into something new and even more exciting."



Audi first featured a full-LED headlight design in 2008 on its R8. They are also used on the A6 luxury sedan. On the A8, ten LED modules make up the low beam in a wing-shaped pattern, while an underlying string of 22 white and 22 yellow LEDs constitute the daytime running lights and turn signals. The white LEDs use a color temperature of 5500K to match daylight and enhance contrast of roadway objects.


The LED luminaire design is combined with intelligent features such as a high-beam assistant that automatically detects the headlights of oncoming traffic and the rear lights of other road users and responds by varying the position and width of the LED headlights accordingly.
Audi has stated that in the first year of sales, cars equipped with LED headlights accounted for a reduction of 25,000 tons of CO2 emissions. LED headlights are four times as efficient as halogen lamps and they require the vehicle’s alternator to replenish less energy, saving fuel.


LED market grew almost 10% in 2011, with 44% growth in lighting


The worldwide LED market grew 9.8% to $12.5 billion in 2011, with 44% growth in the lighting sector, according to Strategies Unlimited, who revealed the top-ten LED suppliers for the year. However, the outlook remains roughly flat for the next 5 years, peaking in 2013.
The worldwide high-brightness LED market grew from $11.3 billion in 2010 to $12.5 billion in 2011, a growth rate of 9.8%, according to market-research firm Strategies Unlimited. Demand for LED components (i.e. packaged LEDs) in the lighting market grew 44%, from $1.2 billion to $1.8 billion.


However, looking ahead, the annual revenues for packaged LEDs are likely to stay approximately flat for the next five years. The growth in revenue from the lighting sector will be largely offset by a decline in the backlighting sector.


The latest HB-LED market update was revealed during a pre-conference Investor Forum at the Strategies in Light event in Santa Clara. Analyst Ella Shum of Strategies Unlimited will go into more detail on HB-LED market developments in the keynote session of the conference on Wednesday February 8.


Leading LED suppliers for 2011
On the supply side, 10 companies accounted for more than 68% of the LED market in 2011. Strategies Unlimited arrived at these figures after analyzing market demand as well as the supply-side activity of 54 LED component suppliers.


The rank order of the top 10 suppliers in the LED market for 2011, by revenue of packaged LED components, is:
1. Nichia 
2. Samsung LED 
3. Osram Opto Semiconductors 
4. LG Innotek 
5. Seoul Semiconductor 
6= Cree* 
6= Philips Lumileds* 
8. Sharp 
9. Toyoda Gosei 
10. Everlight
(*Companies have the same ranking when the difference in revenue is within the margin of error. Revenue includes packaged LED sales only, so pure-play LED chip companies such as Epistar are excluded).


LED supply by region
Geographically, Taiwanese and Chinese suppliers gained market share at the expense of the other regions. China’s improvement in product quality, coupled with gains in the domestic market, fueled the growth from 2% market share to 6% in one year. Korean companies lost share in the slowing market, even though they were the most aggressive in increasing capacity during the ramp-up in 2010.


The expansion by Philips Lumileds, Cree and Osram Opto into 6-inch substrates slowed as there was a great deal of excess capacity in their existing 4-inch lines. The Japanese LED business has trended down or flat. However, Nichia and TG are major beneficiaries of the boom in tablet computers. Osram Opto gained a major design win, which propelled its visible LED component business to more than $1 billion.


Market growth by segment
Mobile 
This segment stayed flat in 2011, at $3.4 billion. The overall decrease in the mobile phones market was offset by a sharp rise in tablet display and flash applications. A major development in this segment is the move to OLED displays. Approximately 50% of smartphone displays are expected to be OLEDs by 2016.


TV/Monitor backlights 
The LED revenue for TV and monitor backlights was $3 billion in 2011, but it is projected to drop substantially by 2016. The key disruptive factor in this segment is the introduction of low-cost, direct-backlit technology, targeted at sub-42-inch LCD TVs. This new technology can result in significant savings in the bill of materials (BOM), reducing the gap between LED- and CCFL-backlit TVs. These TVs are known as “chubby TVs” since they are thicker than the slim edge-lit design the industry has been touting for the past few years.


Lighting 
The same supply conditions that reduced the price of LEDs increased the demand for packaged LEDs in lighting applications from $1.2 billion in 2010 to $1.8 billion in 2011. System efficacy, rather than LED efficacy, was the gating factor in 2011. The LED luminaire and replacment lamp market was $9.3 billion in 2011, an increase of 45% over 2010. The market for LEDs in lighting is expected to demonstate substantial unit growth over the next five years, but revenue growth will be much lower due to pricing pressure.


Automotive 
Revenue reached $1 billion in 2011 We expect a 5-year CAGR of 34% for LED headlamps. In addition to the styling issues, this is part of the trend to convert all front lighting to LEDs, as it will provide more front-end room for the car designer and reduce the overall system cost. Revenue for interior automotive lighting will show a modest decline over the next five years as instrument panel adoption reaches saturation and the market declines with prices.


Future growth
The revenues for the LED packaging industry are expected to be flat in the next five years. With excess capacity in the industry there is a threat of unsustainable prices. Consolidation – both vertical and horizontal – can help improve margins. To further improve profit margin, product strategies such as LED packages tested for high temperature, narrow binning, high CRI, directional /multidirectional LEDs, and embedded controls are being tried by the market.


Friday, April 20, 2012

Munich airport tests ewo LED flood lights for aprons and taxiways


In a new pilot project, ewo has installed LED flood lights on two high masts in the Munich airport, achieving 46% energy savings.
LEDs consume less energy than HPS

Ewo, a manufacturer of LED lighting systems for use in public spaces based in Italy, has installed LED flood lights for the apron and taxiway areas of the Munich airport. The installation indicates a reduction in energy consumption of 46 percent relative to the high-pressure sodium (HPS) fixtures that were replaced.
The project involved two high masts; each mast used six F32 flood light luminaires. In the apron areas, 32 DP31 light modules were installed (consuming 542W), while 24 DS32 light modules (consuming 406W) were used in the taxiway. Nine Cree XP-G LEDs were installed per module, each with an output of 130-lm-per LED at a color temperature of 5500K.
Each mast has six luminaires

In total, the flood lights illuminate a 95 x 350-meter area (33,000 m2 or 357,000 ft2) in accordance with the standards of ICAO guidelines and in compliance with the EN 12464-2 standard (lighting of outdoor work places). Cost and complexity of the project were reduced by using the existing masts and fixtures; mast height is 24 meters. In some cases, optical lenses were added to ensure the taxiway behind the apron was also illuminated according to specifications. The LED flood lights also use a digital addressable lighting interface (DALI) control system to provide further energy-saving potential through dimming. Illuminance is 30 lux at ground level.


F32 LED flood lights

Ewo performed a calculation of the energy savings associated with installing seven high masts in the airport. Total power consumption for the LED flood light fixtures would be 18 kW. Relative to the HPS lights, which use four 100W and three 400W bulbs per mast and consumed 38.5 kW, the savings is 46 percent or 86.1 kW/yr based on an energy cost of 0.12 €/kWh and 4200 hours of lighting per year. The estimated savings in greenhouse gas emissions is 51,600 kg CO2/yr based on an energy mix of 600 g/kWh.
ewo has also installed LED flood lights at the Innsbruck airport in Austria. This larger installation involved 14 high-mast systems. The energy savings was estimated at 70 percent.




Thursday, April 19, 2012

Osram Opto Semiconductors and Arquiled partner on all-LED supermarkets in Portugal


New supermarkets owned by the Jerónimo Martins Group have been equipped with intelligent LED fixtures from Arquiled that use LEDs from Osram Opto Semiconductors.
The all-LED supermarket

The Jerónimo Martins Group has installed all-LED lighting inside and outside its new supermarkets located in Portugal. The first installation took place in 2011 in its Recheio store in Torres Vedras, a region north of Lisbon. The installation uses LEDs from Osram Opto Semiconductors and luminaires and intelligent light management system from Arquiled, a Portuguese lamp manufacturer, to reduce energy cost for lighting by up to 50 percent. The lighting in the shopping and outdoor areas will be used as a model and reference for the chain’s other stores. The second installation will take place in a store in Tavira, Portugal.
“Apart from the performance and efficiency of the products, which are unparalleled on the LED market, another winning feature of the LEDs from Germany is the excellent local support we receive,” said Rafael Abelha Santos, CEO of Arquiled.
Intelligent LED luminaires used at a gas station

Arquiled developed the luminaires for the project based on a detailed assessment of the retailer’s lighting requirements. A key advantage to using LEDs in supermarkets is the fact that they emit little thermal energy and therefore can be placed close to food to illuminate it directly without damage. Three Arquiled modules are to be used at the Jerónimo Martins in Tavira: the Arquiway, a module that uses four Oslon SSL LEDs; the Arquistore, with 72 Oslon SSL LEDs per luminaire; and Arquishelf luminaires, which provide shelf lighting using 56 Oslon SSL LEDs.
The Jerónimo Martins Group is among the first European retail companies to equip its new stores entirely with LED lighting, including the outdoor parking lot and integrated gas stations. The Arquicity street lamps incorporate light sensors and can adjust light levels automatically. Antonio Sousa of Osram Opto Semiconductors in Portugal said "The technical properties of the LED technology will help to achieve considerable savings on power consumption and offer numerous advantages in terms of installation and maintenance, too. That means we save three different resources: power, time and money."


Sunday, April 15, 2012

LED products make up 18% of lighting sales at Philips


LED products continue to grow in importance for Philips’ lighting business, while new LED families have been introduced by Philips Lumileds.
Philips has revealed that sales in its lighting business were EUR 2.072 billion for the fourth quarter of 2011, (from total company sales of EUR 6.7 billion). The company said that its LED-based sales (including all types of products, from packaged LEDs to lamps and luminaires) grew 37% compared to Q4 2010: LED products now represent 18% of total Lighting sales (or EUR 373 million for the quarter).


Philips’ sales

Philips’ overall Lighting sales for the quarter increased 7% year-on-year, driven by double-digit sales growth in the Lamps and Automotive groups, and mid-single-digit sales growth at Professional Luminaires, but this was partly offset by a sales decrease at Lumileds, the company’s LED-manufacturing subsidiary. Lumileds will be hoping that its new CEO and new product lines such as the multi-LED Luxeon K modules (see below) will reverse this trend.
Earnings before interest, taxes and amortization (EBITA) for the lighting business were EUR 41 million, compared to EUR 198 million in Q4 2010. Philips said that the year-on-year EBITA decrease was due to “continued operational issues at Consumer Luminaires and Lumileds, as well as macroeconomic factors which impacted pricing in our consumer lighting businesses.”
In 2011, Philips’ total sales for lighting were EUR 7.638 billion (see chart), of which 5%, or EUR 380 million (approx. $500 million) was from packaged LEDs (i.e. Lumileds).


Philips Luxeon M

In comparison, Cree’s revenue for LED products (including LED components and chips, but not lighting products) was approximately $760 million in 2011.
Elsewhere, Philips said that its sales of all LED-based products amounted to EUR 1.2 billion in 2011, up from EUR 1.0 billion in 2010. The company described itself as “the largest LED luminaires company” and said that its “LED lamps market share exceeds our share in conventional lamps.” Also mentioned was that Philips’ LED licensing program has over 140 licensees.


According to an article on the Smart Planet website, Philips CEO Frans van Houten indicated that the company could soon cut prices on LED light bulbs. A spokesperson for Philips was quoted in the article as saying: “We expect that prices of LED light bulbs will go significantly down in the next couple of years because of product/cost innovation and volume, thereby lowering the threshold for LED light-bulb adoption.”


New products join new CEO at Lumileds
Meanwhile, at Lumileds, the company started the year by announcing a new CEO, Pierre Yves Lesaicherre, and has since revealed two new families of LEDs that will be on show at next week’s Strategies in Light meeting.


The Luxeon M is designed for outdoor and industrial LED lighting applications, and is a multichip, 8-watt, 12-volt package on an aluminum nitride (AlN) substrate. A rnage of color temperatures – 3000K, 4000K, and 5700K – will be available with a minimum CRI of 70.


Philips Luxeon K

All the products are “hot tested” and specified at 85°C junction temperature. Luxeon M produces more than 900 lm at 700 mA, and has 120 lm/W efficacy at 350 mA.
The Luxeon K family is a range of LED arrays, with between 4 and 24 LEDs, which are designed for retrofit and downlight LED-lighting applications. The typical flux at 700 mA ranges from 620 to 4455 lm, measured at 85°C.


The CCT will be 2700K, 3000K or 4000K, with a guaranteed minimum CRI of 80 and typical CRI of 85.
Both Luxeon M and Luxeon K will be available in the second quarter of 2012, says Lumileds.




LED North America provides all-LED lighting for Outpost Solar’s headquarters


LED North America has turned the headquarters building for Outpost Solar in Pulaski, TN, into an all-LED facility.


LED North America, an incubator facility for the Department of Energy’s Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN, has completed a large-scale commercial lighting project using LEDs throughout the headquarters facility of Outpost Solar in Pulaski, TN, a maker of solar-energy systems. The project was made possible with an Innovation Grant from the Tennessee Solar Institute.


Wilson Stevenson, president of Outpost Solar, said, “We are very pleased with the light quality of our new building. We believe we are the first commercial industrial building in the TVA [Tennessee Valley Authority] footprint to be completely illuminated using LED lighting.”
Outpost Solar’s 40,000-square-foot manufacturing area uses 180 Manhattan high-bay luminaires, which deliver 7926 lm while consuming 84W for an efficacy of 96 lm/W. The building’s exterior, security and parking lot use 14 LED cobrahead luminaires to save an estimated $20,000 over the life of the fixtures. Both the high-bay luminaires and cobraheads are supplied with a 10-year warranty.


The high-bay luminaires and cobrahead street lights utilize a graphite-foam technology licensed exclusively by LED North America from ORNL to passively cool the LEDs and ensure the lights operate at cooler temperatures. The graphite foam features high thermal conductivity, low weight and a skeletal structure full of air pockets. A network of ligaments in the foam wicks heat away from the LEDs.


The LED lighting in the 4000-square-foot office area consists of 72 ceiling-mount fixtures, each with four 18W LED tubes, and supplied with a 5 year warranty. Energy consumption is estimated to be 55 percent less than that associated with traditional fluorescent lighting.
Andrew Wilhelm, President of LED North America, said, “Any company that is serious about managing their energy costs has to consider LEDs. LED lighting is truly the low-hanging fruit when it comes to controlling energy expenditures.”
Andy Geshwiler, LED North America’s marketing and sales vice president added, “LED lighting makes great economic and environmental sense. Our LED fixtures will improve the light quality of the work environment for your employees and enhance safety and productivity while at the same time reduces energy bills and maintenance expenses.”



Philips and DOE discuss the LED L-Prize lamp, due on sale in February


A joint webcast presented by the US DOE and Philips provided more details of the testing process that was applied to the Philips L-Prize-winning LED lamp, which the company will sell beginning in February for $50.


Philips Lighting and the US Department of Energy (DOE) have jointly presented a webcast on the LED lamp that won the L-Prize competition to find a replacement for 60W incandescent lamps. Philips is assembling production versions of the solid-state lighting (SSL) retrofit lamp in the US, and plans to ship them into distribution in February. The company has set a $50 retail price, although utility incentives will reduce that cost in many cases.


Production version of the L Prize lamp
The new lamp, primarily targeting commercial lighting applications, will deliver 940 lm and Philips is specifying an L70 life of 30,000 hours. The official model number is 10A19/LPRIZE-PRO/2700-900 DIM 10/1. Distributors will get the lamp in early February, and retailers should have the product in stock shortly thereafter.


The DOE announced Philips as the winner of the 60W L Prize back in August. One of the requirements was a manufacturing plan for a candidate lamp. We will see that plan come to fruition in weeks.


The webinar entitled "L-Prize-winning LED A19 replacement: What commercial building owners/operators can expect in 2012" was held January 18 and allowed the DOE and Philips to answer questions about the L-Prize program and the winning lamp. Speakers included Kelly Gordon, program manager at the DOE's Pacific Northwest National Laboratory (PNNL), and Todd Manegold, director of LED lamps and marketing North America at Philips Lighting.


Workhorse 60W
Gordon covered the rationale behind the 60W incandescent as the target of the program, and the process that ultimately yielded the Philips lamp as the winner. Gordon said there are 971 million 60W A-lamps in the US, including broad commercial usage in hotel, restaurant, retail, medial, and other applications. Clearly there is great potential for saving energy with a more efficient lamp.


Side view of the Philips lamp
To illustrate the decidedly difficult L-Prize requirements, Gordon showed a series of graphs that compared available LED omnidirectional lamps with the L-Prize lamp. Fig. 1 shows the lumen output vs efficacy graph for all of the SSL replacement lamps in the DOE Lighting Facts program.


You can clearly see that the L-Prize lamp is top in terms of efficacy and among the brightest LED lamps. Indeed the design delivers light output closer to what's expected from a 75W incandescent. The L-Prize lamp also got top ratings in CRI and color-temperature comparisons relative to the incandescent standard.


Gordon noted that the L-Prize requirements were far more strenuous than Energy Star requirements, and that most available LED retrofit lamps fail to meet Energy Star. She said there are less than 20 LED A-lamps certified to Energy Star and less than half of those are targeted at 60W sockets.


Energy Star status
Manegold was asked about the Energy Star status of the L-Prize lamp. He said, "The product will have Energy Star status in the 2nd quarter," adding that testing is underway. Moreover, Philips has achieved Energy Star compliance with other LED lamps based on a design that was derived from the L-Prize work.


Energy Star specifies that 60W replacement lamps deliver 800 lm at 50-55 lm/W efficacy depending on power consumption. The preproduction L-Prize lamps that the DOE tested delivered just over 900 lm, and greater than 90 lm/W efficacy.


Gordon also detailed how the DOE tested the 2000 sample lamps that Philips manufactured for the L-Prize program. The DOE verified Philips' photometric data, but the more important tests came in long-term lab testing, stress testing and field testing.


Fig. 1.
When the DOE awarded Philips the L Prize, the agency had burned 200 of the lamps continuously for 7,000 hours at an elevated temperature of 45 C. That test has now reached more than 12,000 hours. No lamp has failed, according to Gordon. The DOE extrapolated the data from the 7,000 hours of testing, and estimated that lumen maintenance would be 99.3% of initial output after 25,000 hours of operation, greatly exceeding the 70% required by the L Prize. And color maintenance far exceeds the L-Prize requirements.


Stress tests
Stress tests included exposure to temperature extremes, vibration, and dirty power input. No LED lamps failed. Meanwhile, the DOE put a sample of what it considered high-quality compact fluorescent (CFL) lamps through the same test concurrently with the LED lamps, and every tested CFL failed.


Moving to the field testing, Gordon said, "Those field assessments were completed in the summer and fall of 2010." Testing included quantitative measurement of installed lamps in applications, and subjective review by test subjects.


Manegold summarized a few of the field tests, yielding some interesting facts. In a hotel downlight application, the sub-10W LED lamp was used in place of a 67W incandescent lamp in a 24-hour operational scenario. Accounting for a 55-lamp project, the LEDs delivered annual energy savings of $2,784. In fact that figure covers the higher up-front cost of the LEDs, delivering a quick payback of slightly less than a year.


Essentially the same test was repeated with 32W CFL lamps. The savings aren't as significant, but payback is still 2.3 years.




Saturday, April 7, 2012

Outdoor Lighting: Cree LEDs light Asheville; Monterrey and Abu Dhabi launch SSL projects


Asheville will soon have deployed a total of 3643 Cree LED street lights, while Abu Dhabi takes a 20-year outlook on an SSL project, and Monterey and Detroit pursue new SSL retrofits.


Cree LEDway fixtures light Asheville
In the second phase of a city-wide LED street light project, Asheville, North Carolina is installing 2913 more Cree LEDway solid-state lighting (SSL) fixtures. Monterey, California will retrofit all street and tunnel lights with LEDs. Detroit, Michigan and Abu Dhabi, UAE pursue LED projects, while Valparaiso, Indiana documents SSL energy savings.
Asheville projects $260,000 savings
When Asheville completes the second phase of its street-light retrofit, the city will have installed 3643 LED fixtures. The city projects annual savings in energy and maintenance costs of $260,000. That number represents a 50% drop from prior spending levels.
"This exciting initiative helps affirm Asheville’s role as a leader in carbon footprint reduction," said Maggie Ullman, energy coordinator for the Asheville Office of Sustainability. "Upgrading to LED street lights allows us to decrease energy consumption, increase energy efficiency and contribute to the sustainability of our community."



SSL delivers uniform coverage in Asheville
Cree Lighting sells the LEDway fixtures that were originally developed By Ruud Lighting's BetaLED brand. Cree acquired Ruud last year. "We applaud the City of Asheville and Progress Energy for working together for the benefit of its citizens demonstrating the growing trend of cities and municipalities working together to join the LED lighting revolution," said Christopher Ruud, president of Ruud Lighting.
Asheville is funding the project in part with a US Department of Energy (DOE) Energy Efficiency and Conservation Block Grant (EECBG). The city installed the initial phase of 730 LED lights in the first half of 2011. All of the SSL fixtures comply with Asheville's lighting ordinance adopted in 2008 that was intended to reduce glare and light pollution.
Monterey seeks 40% energy reduction
According to the Monterey County Herald, the northern California community plans to retrofit all existing high-pressure-sodium (HPS) street and tunnel lights with LEDs. The project totals 1900 SSL fixtures, and the city projects 40% in energy savings.
The Monterey project will reportedly cost $934,000 with funding coming from a low-interest loan provided by the California Energy Commission. The savings will equate to $103,000 annually. Crews are converting 300 lights per day according to a city engineer.
Abu Dhabi and Detroit SSL projects
In the United Arab Emirates capital of Abu Dhabi, the municipality plans to convert 620,000 HPS lights to SSL fixtures according to The National newspaper. The municipality believes it will save between AED500 million ($136.1 million) and AED1 billion over the course of 20 years after accounting for the cost of the LED lights, and one maintenance cycle in which the lights are replaced.
In Michigan, the city of Detroit is planning an SSL retrofit project in six different areas according to the Michigan Live website. A total of 580 LED lights will replace mercury-vapor lights. A $400,000 grant from the Michigan Economic Development Corporation will fund the project.
This Detroit SSL project follows another recent SSL deployment in the city. A group of partners have contributed to a $1.3 million downtown project managed by the Detroit Economic Growth Corp.
The city of Valparaiso, Indiana has embarked on a project converting both street and traffic lights to LED sources. And according to the Valpo Community website, the city has documented energy savings over the past 9 months.
In the upgrade, the city replaced 90 cobrahead lights with 170 decorative LED fixtures. The older lights cost $24.50 per month each in electricity. The decorative SSL fixtures cost $5.85 each to power, so there is a net savings even with more fixtures deployed. Moreover the city is using timers that turn off half of the decorative fixtures late at night.