The Economist has a look at the rapid spread of small scale solar power systems in Africa, driven by cheap solar panels and low-power led lighting - Africa unplugged.

Off-grid solar is spreading at an electrifying pace. An industry that barely existed a few years ago is now thought to be providing power to perhaps 600,000 households in Africa. The pace of growth is accelerating in a continent that, more than any other, is rich in sunshine (see map). Industry executives reckon that over the next year the number of home-power systems on African roofs will grow by 60-100%. M-Kopa, the market leader, has installed 400,000 systems and, at its current rate of growth, may add another 200,000 to that number over the next year. Smaller rivals such as Off Grid Electric, Bboxx and Azuri Technologies may well double their client base over the same period.

RNE has a look at the energy efficiency revolution in lighting - LEDs will slash energy use for lighting by 95%.

A simple (but not perfect) measure for lighting efficiency is the number of lumens (a measure of light intensity) a lighting source produces per watt. A conventional incandescent bulb gets 13 lumens per watt to light your room, while a replacement LED bulb from Philips that can be bought at Coles or Woolworths achieves 80 lumens per watt (a compact fluorescent globe gets about 60 lumens per watt).

CREE (the industry leader who, it is speculated, may purchase the next best, Philips’ Lumileds division) has successfully demonstrated Light Emitting Diodes running at 300 Lumens per watt in the lab. CREE currently sell a $10, 9.5W bulb (available in the US), which produces 85 Lumens per watt and can directly replace an old style 60W globe.

Other breakthroughs and innovations are contributing to achieving higher efficiency’s in LED lighting, including a breakthrough by German researchers which will not only effect LED lights, but laptop and mobile phone chargers, cutting losses in today’s most efficient power supplies by half from 10% to just 5%.

Taking all this into consideration, according to the US Department of Energy SSL (Solid State Lighting) program http://energy.gov/eere/ssl/solid-state-lighting we should be able to achieve wall plug efficiencies of 250 Lumens per watt by 2020 which means that a conventional bulb replacement in 2020 would be available using only a third of the electricity of today’s LED bulbs.

At that staggering rate of 250 lumens per watt, it will only take 3W to light a room, when it used to be done with 60 Watts of power. This represents a 95% reduction in energy required for lighting.

This will have a profound effect on the world’s requirement for lighting energy. We can expect - on an absolute basis – that 19% of the world’s electricity which is currently used for lighting to dramatically drop by at least 75%. On today’s numbers the reduction is the equivalent of the entire electricity consumption of the European Union.

In developed nations these huge efficiency gains from LEDs in the lighting sector will contribute to the continuing restructure of the electricity supply industry, which is currently facing a death spiral unless it can electrify the remaining residential energy services coming from fossil gas and supply a fast tracked electrification of the world’s vehicle fleet.

In developing countries, rooms that can be lit with 3W and task lights with even lower electricity consumption. This means that almost all the remaining 1.5Billion of the world’s population without an electricity supply will be able to access one at very minimal marginal cost in the next 5 years.

Technology Review has an article on a new LED light design that mimics the old incandescent bulb - Cree Introduces an LED Bulb Edison Would Love.

If you’ve had any experience with LED light bulbs, you know they can look pretty odd. Cree today introduced a bulb that mimics the traditional incandescent bulb design in every way–except its inefficiency.

The bulb is the first consumer bulb from Cree, which primarily supplies LED semiconductors to other lamp makers. There are three products: a 40-watt equivalent and two 60-watt equivalents with different color light. They’re available from Home Depot online now and will be made available in stores this month priced between $9.97 and $13.97.

What’s most notable is that bulbs have the same glass dome as incandescent lights and there isn’t a large metal heat sink. The first wave of general-purpose LED products have heavy metal fins to wick away heat from the LED light sources, which helps ensure life. The Cree bulb uses the same glass as an incandescent but has a rubber coating to prevent shattering.

In an incandescent bulb, a tungsten filament in the center of the glass glows to give off an even, warm light. Cree designed a “filament tower” that places a series of pin-hole-shaped LEDs in the same location as the traditional filament. I installed one yesterday and the effect is a similar light output as a traditional bulb and even light distribution.

Having a familiar shape is very important to spur more consumers to consider LEDs as a replacement for incandescent bulbs, says Mike Watson, the vice president of corporate marketing. “Consumers actually love that particular (incandescent bulb) product. It’s the shape they’re used to and it gives off a warm glow they expect, but it’s grossly inefficient and has a short lifetime,” he says. Cree’s bulb uses high-power LEDs which means it can work with a smaller heat sink, which appears like a collar around the base of the bulb.

An incandescent bulb lasts about 1,000 hours, while most LED bulbs are rated to last 25,000 hours, which can be 15 or 20 years depending on usage. The Cree bulb has a 10-year warranty.

Technology Review has a look at ways to reduce the cost of manufacturing LED lighting - A New Way to Churn Out Cheap LED Lighting.

A startup in California has developed a manufacturing technique that could substantially cut the cost of LED lightbulbs—a more energy-efficient type of lighting.

LEDs are conventionally made on a relatively costly substrate of silicon carbide or sapphire. Bridgelux has come up a new process takes advantage of existing fabrication machines used to make silicon computer chips, potentially cutting LED production costs by 75 percent, according to the company.

Despite their higher efficiencies and longer life, few homes and businesses use LED lighting—largely because of the initial cost. An LED chip makes up 30 to 60 percent of a commercial LED lightbulb. Electronic control circuits and heat management components take up the rest. So for a 60-watt equivalent bulb that costs $40, Bridgelux's technology could bring the cost down by $9 to $18. Integrating the light chip with the electronics might further reduce costs.

LEDs made with the new technique produce 135 lumens for each watt of power. The U.S. Department of Energy's Lighting Technology Roadmap calls for an efficiency of 150 lumens per watt by 2012. Some LED makers, such as Cree, in Durham, North Carolina, already sell LED lamps with efficiencies in that range. In contrast, incandescent bulbs emit around 15 lumens per watt, and fluorescent lightbulbs emit 50 to 100 lumens per watt.

Inhabitat has a post on Philips' new LED light globe - Philips Unveils World’s First LED Replacement for Most Common Bulb.

There are over 425 million 60 watt incandescent bulbs sold every year, which makes the energy-sucking globes the most commonly used bulbs in the United States. Lighting the way to a more energy-efficient tomorrow, Philips has just unveiled the 12-watt EnduraLED – the world’s first replacement for the commonly used 60 watt incandescent. The EnduraLED is capable of lasting 25 times longer than a standard incandescent and only consumes 20% of the energy. If all the bulbs in the states were switched to these LEDs it would save 32.6 terawatt-hours of electricity each year — enough energy to power 17 million homes.

Technology Review has an article on "solar-cell manufacturing techniques [which] could yield LEDs that require 20 percent less energy" - Green LEDs for Efficient Lighting.

A new approach to fabricating light-emitting diodes (LEDs) could be used to increase their efficiency by 20 percent while yielding higher-quality light than conventional LEDs. Researchers at the National Renewable Energy Laboratory (NREL) in Golden, CO, have demonstrated the approach by making a yellow-green LED that could soon be combined with other colored LEDs to yield white light. The new LED could help replace current, inefficient methods of generating white light.

LEDs, devices that emit photons when an electrical charge is applied to them, are more efficient and last longer than incandescent lightbulbs. By varying the composition of the semiconductor LEDs, materials scientists can coax the devices into emitting different colors. At the minimum, producing white light requires combining red, blue, and green, but so far, only red- and blue-light-emitting diodes are well developed. To produce green light, LED manufacturers typically apply one or more phosphor materials to blue LEDs. The phospors convert high energy blue spectrum light into lower-energy light through a process that reduces overall luminosity by approximately 20 percent.

To eliminate this loss of efficiency, researchers have tried to develop efficient green LEDs that don't require phosphors. But a major stumbling block is that the different known semiconductor materials that can be combined to emit green light, typically indium and gallium nitride, have different-sized crystal lattice structures. For semiconductors to work efficiently, each layer of the device has to have a similarly sized lattice structure as the layer above or below it.

To get around the lattice-size mismatch, NREL researchers used a fabrication method that they had previously developed for building highly efficient multi-junction solar cells. Their method relies on using additional layers of other semiconducting materials with intermediate-sized lattice structures that bridge the gap between the disparate-sized semiconductors. "If you try to do it in one shot, the whole thing will be defective," says Angelo Mascarenhas, team leader for solid state spectroscopy in the Center for Basic Sciences at NREL. "You have to grow a sequence of layers in a step-wise fashion."

Inhabitat has a post on tomato powered illumination - Table Lamp Powered Completely by Tomatoes!.

We all know tomatoes pack a powerful acidic punch, but we never thought we’d see one lighting up a room! Cygalle Shapiro of Israel-based d-VISION has created an incredible LED lamp that is completely powered by real, edible tomatoes. Currently exhibited at the Milan Furniture Fair, the design collects energy from a chemical reaction between tomato acids, zinc, and copper. This design doesn’t only explore advances in lighting technology – its also an art piece that sends clear and powerful social-conscience messages about where and how we receive energy.

d-VISION’s tomato lamp calls attention to the amount of natural resources needed to produce even the smallest amount of power for everyday living. Although the tomato lamp utilizes an organic energy source, it still takes a considerately large amount of tomatoes just to power one lamp. The lamp holds power until the tomatoes go stale, signaling a beginning and end to energy sources. The designer highlights value by creating the tomato-powered circuits and lamp completely out of gold.

Technology Review has an article on a new approach to wiring up LED lighting in order to make it even more energy efficient - Smarter LED Lights.

A new approach to LED lighting uses network cables, rather than conventional electrical wiring, to supply power to lights. Developed by a startup in Fremont, CA, the system also allows the cables to carry data from an array of sensors on the lights to a central control station. The system would cost about the same as a conventional lighting system, but because it can sense and control every light in a building, it could cut power consumption from lighting by 50 to 80 percent.

The new system offers a better way to control LEDs, which are relatively efficient and long-lasting compared to conventional lights, by taking advantage of the fact that they run on low-voltage direct current power. Current LED-based systems require transformers at each light to convert the higher-voltage alternating current in conventional wiring into lower-voltage direct current. The new system converts alternating current to low-voltage direct current at a central location, rather than at each light. This more efficient method cuts energy consumption by 10 to 20 percent, according to Jeremy Stieglitz, vice president of marketing for Redwood Systems, which will start selling its systems this summer.

The remaining energy savings come from using sensors and a central controller to reduce light use. The company has also developed a method for using those same power cables to carry data. Each LED can be fitted with inexpensive sensors that can be used to optimize light levels and ensure the lights are operating efficiently. Such sensors can also provide detailed information about temperature and where people are in the building--information that can be used to control heating and cooling systems. The sensing and controls, says Steiglitz, add very little cost to the new system because the network connections and power supply for the sensors are already in place.

Inhabitat has a post on an elegant and efficient design for streetlights - Solar Flower Petal Street Lamps Bloom by Day, Illuminate the Night.

Designed for the Phillips Simplicity Event in 2008, the Sustainable City Light is an intelligent outdoor lighting system meant to enhance city life by providing accurate lighting on demand as needed. The LED lights feature motion sensors that are triggered once the sun sets by individuals walking in close proximity to the light. If no one is around, the lights conserve energy by remaining off.

Powered by the sun, the street light blooms open during the day to collect energy through its solar panels. The five solar panel petals generate more than enough power to keep the lights on and any extra power is fed directly into the grid for use elsewhere.

Inhabitat has a post on a long life, energy efficient LED light - New Super Efficient Pharox 60 LED Bulbs Last for 25 Years.

One of the most exciting new products we found at West Coast Green this past weekend is the latest innovation by Lemnis Lighting, the Pharox 60 LED Dimmable Lightbulb, that uses just 6 Watts and has the equivalent luminescence of the traditional 60 Watt incandescent bulb. The Pharox 60 fits a standard sized household light fixture, is made of recyclable material, and is the most energy efficient bulb of comparable light quality on the market today with a light output of 300 lumens and a warm white light of 3000K. A patented heat sink keeps the bulb temperature low (we think it’s the aluminum housing surround) and it is the most environmentally safe option on the market as well, containing NO lead, mercury, or wolfram, unlike it’s compact fluorescent competitors.

Compared to the incandescent bulb, which lasts an average 1,000 hours, the Pharox 60 is expected to last a 35,000 hour lifespan. According to Lemnis, if every American household switched just one 60W light bulb to a Pharox light, $1.4 Billion in electricity costs and 9 billion kilowatt hours would be saved annually.

Technology Review has an article onfFlexible arrays of inorganic LEDs which could mean cheap, energy efficient displays and lighting = Cheaper LEDs.

A new technique makes it possible to print flexible arrays of thin inorganic light-emitting diodes for displays and lighting. The new printing process is a hybrid between the methods currently used to make inorganic and organic LEDs, and it brings some of the advantages of each, combining the flexibility, thinness and ease of manufacturing organic polymers with the brightness and long-term stability of inorganic compounds. It could be used to make high-quality flexible displays and less expensive LED lighting systems.

Inorganic LEDs are bright and long lasting, but the expense of manufacturing them has led to them being used mainly in niche applications such as billboard-size displays for sports arenas. What's more, the manufacturing process for making inorganic LED displays is complex, because each LED must be individually cut and placed, says John Rogers, a materials science professor in the Beckman Institute at the University of Illinois at Urbana-Champaign. So display manufacturers have turned to organic materials, which can be printed and are cheaper. While LED-based lighting systems are attractive because of their low energy consumption, they remain expensive. The new printing process, developed by Rogers and described today in the journal Science, could bring down the cost of inorganic LEDs because it would require less material and simpler manufacturing techniques.

The Energy Collective has a post on the transition to energy efficient LED lighting - The Transition to LED Lighting.

In a new paper (subs req'd) published as the cover article in the March edition of the Proceedings of the IEEE, the authors take a comprehensive look at technology, costs and policies influencing the adoption of light emitting diode, or LED, lighting. The 30-page (!) journal paper, authored by colleagues Inês L. Azevedo (A Sustainable Research contributor), M. Granger Morgan and Fritz Morgan is titled, The Transition to Solid State Lighting.

90% of U.S. residential lighting is provided by incandescent bulbs, which is bad news and good news. The bad news, the authors tell us, is that incandescent bulbs only convert between 0.2-2.6% of the electricity consumed into useful life. This inefficiency should be no surprise, as an incandescent is essentially a little fire enclosed in a bulb. The good news is that they are cheap and generally last less than a year before the bulb burns out. This means that unlike cars or buildings, replacing our "fleet" of residential light bulbs has a relatively short time-scale. But what do we replace with? This spring the NY Times discussed the promise of LEDs, but this week is reporting that the death of incandescents has been greatly exaggerated. The authors of this paper discuss the comparative advantages of solid-state lighting, or LEDs.

When talking about lighting, we need to get the terms right. System Efficacy is a measure of how much light is perceived by the human eye (lumens) vs. how much power you need to produce it (Watts). You want the most light you can get for the least amount of power. This is outlet-to-eye efficiency, so to speak, so it considers losses starting at the lighting ballast (the part at the base of CFL, for example), losses in the bulb itself, and then losses in whatever cover we put over it (e.g., the glass). The authors report a system efficacy in lumens per watt for the following bulbs: Incandescent (2-16 lm/W), Halogen (6-30 lm/W), Fluorescent Tube (16-90 lm/W), CFL (9-68 lm/W), HID (4-120 lm/W), and finally a white LED (18-170 lm/W). Translation: LEDs good, could get better.

The paper also presents method to evaluate costs from different lighting technologies, and in the middle of a technical paper they present a refreshing review of discounted utility models and economic theory, and give some insight into how we make (sometimes really bad) decisions about what technologies we buy. For instance, the paper reviews studies that estimate residential consumers apply implicit discount rates to energy efficient appliance purchases of up to 300%! This means they aren't willing to pay a little more up front for a more efficient appliance that will clearly save them money over time, unless that money saved is large enough to be seen from space. [N.B. My proposed solution to this, is a tax credit for credit card companies to offer a energy star credit card, with a fixed rate of 5%, that can only be used to purchase energy star products, but I digress.]

The paper continues through scenarios about U.S. lighting demand, and energy savings through LED adoption. They report: "A solid-state lighting adoption of 5%, 50%, and 99% in terms of lumen demand would provide cumulative savings between 2007 and 2015 from 20 to 50 TWh, from 125 to 340 TWh, and from 385 to 1030 TWh for the residential sector; and from 25 to 30 TWh, from 90 to 110 TWh, and from 430 to 525 TWh for the commercial sector, depending on the assumptions made about future lighting demand."

They go on to estimate that LEDs will be among the lowest cost options for of carbon mitigation (that's $/ton avoided): "According to our simulations, the cost-effectiveness of mature lighting technologies ranges from 4 to 28 $/ton CO2. Assuming a 10% discount rate, solid-state lighting cost-effectiveness for a utility ranges from 34 to 134 $/ton CO2 in 2008 and from 4 to 14 $/ton CO2 in 2015, making it among the more attractive investments available for large CO2 abatement by the electricity sector."

Technology Review has an update on quantum dot OLED technology - A Cheap Route to Robust LEDs.

Organic light-emitting diodes (OLEDs) are steadily making their way into commercial devices like cell phones and flat-screen displays. They're fabricated with layers of organic polymers, which make them flexible, and they use less power and less expensive materials than liquid crystal displays.

The downside is that because the polymers react easily with oxygen and water, OLEDs are expensive to produce--they have to be created in high-vacuum chambers--and they need extra protective packaging layers to make sure that once they're integrated into display devices, they don't degrade when exposed to air or moisture.

MIT chemical-engineering professor Karen Gleason and MIT postdoc Sreeram Vaddiraju have developed a process that aims to solve the problems of high fabrication costs and instability for OLEDs while still maintaining their flexibility. Gleason's solution is a hybrid light-emitting diode, or HLED. The device would incorporate both organic and inorganic layers, combining the flexibility of an OLED with the stability of an inorganic light-emitting material. "The idea is to have a mixed bag and capture the qualities that allow inexpensive fabrication and stability," Gleason says.

Gleason starts with a substrate of electrically conducting organic polymer, which she creates through a chemical vapor deposition process in a low-vacuum chamber. It's the only step in the process that requires a vacuum, which should make the approach cheaper than conventional methods. For the light-emitting layer, Gleason uses quantum dots, nanocrystals of inorganic semiconductors; each quantum dot can be "tuned" to emit certain frequencies of light. Although quantum dots are inflexible themselves, they're so small--two to six nanometers across--that even arranging them side by side in a continuous film still allows for flex in the material.

Technology Review has an update on cheap, energy efficient OLED lighting - Ultra-Efficient Organic LEDs.

An organic light-emitting diode (OLED) developed in Germany has the potential to produce the same quality of white light as incandescent bulbs but with power efficiencies considerably better than even fluorescent lighting.

The prototype OLED could emerge as an ultra-efficient light source for displays and general lighting, says Sebastian Reineke, who led the research at the Institute for Applied Photophysics, in Dresden, Germany. The long-term goal is to fabricate the device using conventional low-cost roll-to-roll printing.

In recent years, many countries have begun looking to switch from incandescent lighting to compact fluorescent bulbs because the latter are so much more energy efficient. There has also been a lot of interest in using light-emitting diodes (LEDs) for displays and general lighting, again because of the potential energy savings they offer.

But with both fluorescent and LED lighting, the quality of white light produced has always left something to be desired. Fluorescent lighting can make people appear unhealthy because less red light is emitted, while most white LEDs on the market today have a bluish quality, making them appear cold.

In contrast, OLEDs can be made from a wide range of materials, so achieving good-quality white light is less challenging, says Reineke. It has not been the quality of light that has let OLEDs down but rather their efficiencies. Fluorescent lighting typically operates at around 60 to 70 lumens per watt, while incandescent bulbs operate at about 10 to 17 lumens per watt. In contrast, says Reineke, the best reported power efficiency of an OLED until now was 44 lumens per watt.

In this week's issue of the journal Nature, Reineke and his colleagues report a novel structural design for an OLED that exhibits efficiencies of 90 lumens per watt and shows potential to go up to 124 lumens per watt.

"These efficiencies are very compelling," says Peter Kazlas, director of device development for QD Vision, a company based in Cambridge, MA, that's developing quantum-dot-based LED lighting.

"OLEDs have the potential to grow into a really very energy-efficient light source," adds Kristin Knappstein, business-development manager at Philips Lighting, in Aachen, Germany. Her company already has an OLED lighting product on the market called Lumiblade. "In production, we achieve levels of between 15 and 20 lumens per watt," she says, adding that the ultimate potential is for the technology to reach efficiencies as high as 150 lumens per watt.

Seth Coe-Sullivan flicks the switches on two desk lamps, and even from across the conference room, it's immediately obvious which light the chief technology officer of QD Vision is there to brag about. The light coming from the lamp on the left is a harsh bluish white. The lamp on the right casts a warmer, more yellow glow. Coe-Sullivan holds a hand under each lamp. The hand under the bluish light looks pale and sickly; the other looks darker and healthier. The harsher light lacks wavelengths in the red end of the spectrum, so there's no light to illuminate the reddish tinge that blood provides to human skin.

QD Vision, based in Watertown, MA, is promoting a new LED-based lamp that it made with Nexxus Lighting of Charlotte, NC. Nexxus makes a lamp designed to screw into standard sockets used in recessed ceiling lighting. It consists of an array of white-light LEDs encircled by fins that remove excess heat. QD Vision adds an optic--a plastic cover with a special coating that snaps into place over the LEDs.

It's that coating that makes the difference in the quality of the light. It consists of quantum dots--tiny bits of semiconductor material just a few nanometers in diameter. When excited by a light source--in this case, the LEDs--quantum dots radiate light in a wavelength that varies according to the size of the dot: a two-nanometer dot gives off blue light, a four-nanometer dot emits green, and a six-nanometer dot produces red. The company makes the dots in controlled sizes, then mixes them in the right ratio to get the desired color.

This color-tailoring ability solves one of the major problems with using LEDs for general lighting applications. LEDs are appealing because they last for years, use perhaps 20 percent of the electricity of a standard incandescent bulb, and are highly efficient at converting electricity into visible light instead of into heat. But to make white light, you either have to mix together LEDs of different colors or use a blue LED coated with a phosphor that emits yellow light to produce a whitish mix. The problem with the phosphors is that they don't emit evenly across the visible spectrum. They tend to have gaps in the green section and even more so in the red, leading to the harsher, bluish light. "You can't precisely tailor phosphors anywhere in the visible spectrum," says Dan Button, QD Vision's CEO.

Next100 has a report on the introduction of LED street lighting in some sections of San Francisco - Brightening Up San Francisco's Tenderloin.

San Francisco's gritty Tenderloin district will shine a little brighter thanks to a new streetlighting program announced today by Mayor Gavin Newsom, the San Francisco Public Utilities Commission and PG&E.

Newsom press conf 3-25-09.JPGAt a press conference this morning on Turk St., joined by PG&E's senior vice president for public affairs, Nancy McFadden, Newsom said the city is installing 50 ultra-efficient, energy-saving LED streetlights in the depressed neighborhood, a smart move to enhance public safety while demonstrating environmental leadership and saving money.

In addition, city authorities are working with PG&E to evaluate "smart controller" technology that will monitor the performance of individual streetlights, adjust their intensity, and signal when they are about to fail. Flexible controls will give officials to ability to turn selected lights on or off, dim them, or flash them to alert emergency personnel.

As NEXT100 reported in February, a pilot test of LED streetlights outside PG&E's headquarters on Beale St. in San Francisco helped pave the way for this announcement by demonstrating that remote management of LED streetlights can potentially save money by providing real-time billing information and automatic alerts to field repair teams. (Test lights are also in operation near City Hall on Fulton, between Larkin and Hyde.)

Cities also stand to save money simply by virtue of the fact that LEDs use only half the energy of traditional streetlights and last two- to three-times longer. Adding to their luster, PG&E is developing special energy rates and rebates to encourage cities to install LED streetlights.

CNet has an article on the shift towards energy efficient LED lighting by Philips - Philips Lighting rides analog-to-digital wave.

The lighting industry is changing from analog to digital technologies, a move that could bring traditional semiconductor and IT suppliers into lighting, said Philips Lighting CEO Rudy Provoost.

Before heading the 117-year-old Philips Lighting business, Provoost was CEO of Philips Consumer Electronics, a position that gave him a good understanding of the digital world.

"Over time, as the shift from analog to digital technology continues, we will indeed see companies in the ICT (information and communications technology) world probably get involved in digital lighting," he said.

Potential new competitors would be Asian high-tech manufacturers or semiconductor makers, he said. "The question is not if but how. That landscape is going to change."

Philips is pushing hard into solid-state lighting, having spent about $4 billion acquiring LED (light-emitting diode) lighting companies over the past two years. Provoost this week is in the U.S., where some of those acquired companies are, including LED lighting firm Color Kinetics and Genlyte.

Energy-efficient lighting is one of the areas that is expected to benefit from a government-led stimulus package, which has provisions for retrofitting government buildings, schools, and municipal buildings.

Provoost said that LED lighting is far more efficient than alternatives--five times more than incandescent and halogen lights and at least as efficient as fluorescents--and they last longer than others.

The most promising areas in the short term for LED lighting are office buildings, shops, outdoor lighting for city "beautification" projects that use colored lights, and in consumers' homes.

Fast Company and New Scientist have reports predicting that cheap GaN based LED lights may soon make both ncandescent and compact fluorescent light globes obsolete - Better, Cheaper LEDs Ringing Death Knell of Fluorescent Bulbs.

LED lighting has long been viewed as a superior alternative to compact flourescent bulbs. Although flourescents are more electrically efficient than old-fashioned incandescent bulbs, producing them requires a complex procedure that uses a little mercury--a big environmental and health no-no. Indeed many are questioning whether CFLs are actually an environmentally-friendly choice at all.

So why aren't we using LEDs in our homes already? The problem is that CFLs are still cheaper to manufacture than LEDs. But now scientists at Cambridge University haved invented a process that promises to make the lighting technology even more energy efficient and cheaper to produce.

The new manufacturing process is identical to commercially-used systems for making other chips, which is why the cost is phenomenally low. In fact a 15cm wafer will cost around $15, and can fit in 150,000 GaN LEDs: making the core component of the device (before it gets wrapped in the familiar plastic bubble, and given conducting connections) a mere $0.0001.

LEDs are little slices of layered semiconductor, carefully arranged so that electrical current flowing through them excites the material into producing light. They work instantly, requiring no warm-up, they're small, easy to manufacture, and are very efficient at turning electrical power into light without generating waste heat.

Current gallium nitride (GaN) LEDs are limited however by the complexity and cost of manufacturing them. Unlike other semiconductor devices, they can't be fabricated on silicon--after being deposited in layers the GaN physically contracts twice as fast at the silicon base, leading to deformed and cracked devices that won't work. Current solutions to this problem involve growing GaN LEDs on saphhire, which has the same rate of shrinkage after the 1000ºC manufacturing process. But, of course, including sapphire in the devices pushes their cost much higher.

The Cambridge team worked out that by incorporating thin layers of another material--aluminum gallium nitride--into the structure of GaN LEDs, the resulting devices can tolerate the shrinkage and still work as light sources. ...

LEDs are easier to make [than CFLs], potentially more electrically efficient, smaller--and thus more design-customizable--and last up to 10 times longer than CFLs. The new invention means we'll see them lighting our homes and offices before you know it. Doing so will apparently drop the amount of electrical energy needed nationally for lighting from 20% to 5%.

Wired has a post on a plan to introduce energy efficient LED streetlighting to New York city - Big City, Brighter Lights: Gotham's New LED Streetlamp Plan.

After half a century of walking their dogs under the same old streetlamps, New Yorkers are ready for a new age of enlightenment. Gotham's own Office for Visual Interaction won an international competition to design a replacement. Its inspiration: LED headlights. "We took the same idea and made it vertical," OVI's Enrique Peiniger says. The new lamppost's 4-to 6-foot head boasts up to 100 LEDs with multiple lenses that can be configured to dial in specific lighting "footprints" of uniform brightness. For New York, the coverage patterns will be tailored for three distinct situations—park, street corner, and mid-block.

How many workers will it take to change the bulbs? A lot fewer. LEDs last twice as long as the current high—pressure sodium bulbs. Oh, and they burn 30 percent less energy. Plus, the fixture's modular design makes it easy to swap out chips as LED technology improves. OVI is putting the finishing touches on its prototypes, and if tests go well next year, the lamps will soon start lighting up the city that never sleeps.

Greentech Media has an article on growing interest in the energy efficient lighting (ie. LED) market - Will the Computer Giants Invade Lighting Too ?.

This year, we saw Intel, IBM, LG and others jump into the solar market, following a path blazed by Applied Materials two years ago.

Cisco, Freescale and several startups like GainSpan are busy porting wireless chips and equipment originally designed for consumer electronics and computers into smart meters and energy efficient appliances. WiMax, the wireless broadband protocol, is coming to connect homes and utilities.

What will the computer world colonize next? Probably lighting.

Solid state light sources such as LEDs, plasma lights and OLEDs are expected to become popular over the next five to ten years as the price declines and mass manufacturing cranks up. Right now, LEDs are primarily made by the large lighting subsidiaries of conglomerates, like Philips Lighting. The nature of the industry and the technology, however, is opening the door to PC-centric companies.

Foundries, which make computer chips for people who don’t want to own their own factories, will likely enter lighting. Although LEDs are technically chips, the process and chemistry are different than what you need to make computer chips. Still, TSMC, the world’s biggest foundry for silicon chips, is tinkering with strategies to serve as a factory-for-hire for LED designers.

Applied Materials, meanwhile, is examining whether it should make equipment to produce OLED lights, which are thin and somewhat flexible. The OLED process is similar to the thin-film solar process, which in turn is similar to the process for making LCD TVs. (Applied also has a boatload of equipment that can be used to make regular LEDs.)

And then you have companies like HID Laboratories that will use IT technologies to control and dim high-intensity discharge lights. Panasonic is putting automated light and air conditioner controls in green homes in Japan.

Interestingly, the LED companies themselves are moving from making individual chips to entire lighting solutions — i.e., packaged light sources for specific applications or even lamps. Early next year, LED manufacturer Bridgelux, which has raised $71 million already, will release white light LEDs in a variety of color temperatures. Rather than sell them to the general market, Bridgelux will target these for specific applications, said CEO Mark Swoboda. Philips Lighting, meanwhile, will begin to emphasize lamps in the future.

These are the initial burbles of the flood. When you see Intel, Samsung and Cisco talking about the crisis in lighting and their ideas for paving the way to a new world of energy efficient lighting, don’t say you weren’t warned.

The New York Times has a look at the slow evolution of LED lighting - Fans of L.E.D.’s Say This Bulb’s Time Has Come.

The nation’s Big Three of lighting — General Electric, Osram Sylvania and Royal Philips Electronics — are embracing a new era of more efficient technologies, like halogen, compact fluorescent and solid-state devices. Encouraged by legislation and the rising cost of energy, as well as concerns about greenhouse gases, consumers are swapping out incandescent bulbs.

The switch is forcing a fast change in strategy, as companies reposition their manufacturing lines. General Electric, for instance, said earlier this month that it was spinning off its unit that makes bulbs.

The bulb makers face a tough problem. Their businesses were built on customers who regularly replaced light bulbs. How do you make a profit when new lighting may commonly last 50 to 100 times as long as a standard bulb? Compact fluorescents, which use less than one-third the power and last up to 10 times as long as standard bulbs, have replaced incandescent bulbs in many homes and offices.

In some types of commercial buildings, L.E.D.’s are rapidly replacing older products. The industry seems convinced that new lower-cost L.E.D. bulbs, with their improved efficiency, will eventually become the chief substitutes for incandescent bulbs in homes.

L.E.D.’s, including new bulb types and applications, dominated the exhibits at Lightfair, the lighting industry’s annual trade event held in May in Las Vegas. Traditional tungsten bulbs were largely absent. L.E.D.’s were shown for street and parking lot lighting, under-counter lighting, residential bulb replacements and office lighting. They are being used in commercial refrigerators, as substitutes for fluorescents and for illuminating the outside of buildings, allowing for easy color changes. Television production studios are installing L.E.D.’s to save money and eliminate the need for climbing in the rafters to change bulbs or filters.

The problem, though, is the price. A standard 60-watt incandescent usually costs less than $1. An equivalent compact fluorescent is about $2. But in Europe this September, Philips, the Dutch company dealing in consumer electronics, health care machines and lighting, is to introduce the Ledino, its first L.E.D. replacement for a standard incandescent. Priced at $107 a bulb, it is unlikely to have more than a few takers.

“L.E.D. performance is there, but the price is not,” said Kevin Dowling, a Philips Lighting vice president and past chairman of the Next Generation Lighting Industry Alliance, an industry group that works with the Department of Energy. “Even at $10 to $15, consumers won’t buy L.E.D. bulbs,” Mr. Dowling said.

The L.E.D., a type of semiconductor, generates light when an electric current is passed through positive and negative materials. Energy is given off in the form of heat and light. Different colors and greater efficiency are created by altering the composition of the material. Typically, a compact fluorescent bulb uses about 20 percent of the energy needed for a standard bulb to create the same amount of light. Today’s L.E.D.’s use about 15 percent. Next-generation bulbs still in the labs do even better.

While compact fluorescents are beginning to replace standard light bulbs in many homes, lighting executives see those as an interim technology. They say the large size of the bulbs, the inability to dim many of them, the unpleasant color of the light and the five milligrams of mercury in each bulb will limit their appeal.

Philips is working to decrease the penetration of compact fluorescent bulbs. “We are not spending one dollar on research and development for compact fluorescents,” said Kaj den Daas, chairman and chief executive of Philips Lighting. Instead, the bulk of its R.& D. budget, which is 5.2 percent of the company’s global lighting revenue, is for L.E.D. research. Philips is betting the store on the L.E.D. bulbs, which it expects to represent 20 percent of its professional lighting revenue in two years.

Light-emitting diodes (LEDs) are better than compact fluorescent bulbs--LEDs use less energy, last longer, and contain no toxic mercury--but for general white-light illumination, they're still far too expensive for mass adoption. Now, researchers at Purdue University have taken a step toward making white LEDs with cheaper materials.

LEDs are semiconductors that emit photons when a charge is applied. To make white LEDs, you need an LED that emits blue light (the blue light is then either filtered or combined with red and green LEDs, to make white). Today's commercial LEDs generate blue light from a gallium nitride semiconductor expensively fabricated on a sapphire substrate. The Purdue group found a way to build blue gallium nitride LEDs by stacking metallic layers on silicon.

The benefits are several. Silicon is cheaper and available in larger diameters than sapphire is. Silicon also carries away heat effectively, meaning that it can remain in a finished LED device and allow the lamp to last longer and stay bright. Since sapphire is a poor thermal conductor, LEDs grown on the substrate have to be removed and transferred onto a different surface--costly extra steps, says Timothy Sands, director of the Birck Nanotechnology Center at Purdue, who led the research.

Although Sands says that he can't identify an exact cost savings until the devices are manufactured, the cheapness and scalability of silicon are reason enough for him to be "confident that it will be much cheaper [than sapphire]." Other improvements, such as better heat dissipation and reflectivity, also boost performance. The researchers have yet to report how the device's efficiency and total light output compare to that of current LEDs. "What's exciting is the impact this could have on energy savings" that would be derived from cheaper white-light LEDs replacing conventional lighting, Sands says.

The group achieved the trick using metallic layers. Since silicon absorbs light--a negative when the goal is to release it--Sands's group coated the silicon with a layer of zirconium nitride that reflects the downward-traveling light back to the top. To solve a second problem--that zirconium nitride reacts with silicon in a way that degraded the LED--they put a layer of aluminum nitride in between, which prevented these reactions. The last step is the addition of a layer of gallium nitride.