L.E.D.

by Bob Johnstone

  At first, fixture makers had been inclined to regard LEDs as merely a novelty because individual devices could only produce colored light. But white light sources kept getting brighter, as Haitz’s Law predicted, until eventually it became impossible to ignore LEDs and their significance for the future of illumination. By 2009 there could no longer be any doubt. At Lightfair, the industry showcase held in New York that year, there was an explosion of LED lighting products. Marketing people coined a new word to describe the phenomenon: they called it “LEDification.”

  Haitz and Tsao ended their 2010 paper with a de finitive statement. As far as new technology was concerned, lighting had reached the end of the road. Solid-state lighting was approaching the physical limits of conversion efficiency. That meant there were no further energy savings that could be used to finance the next generation of technology. The long march of innovation that over two hundred years had progressed from wax candles and whale oil, through incandescents and fluorescents, was nearing its conclusion. LEDs were humanity’s “last revolution in lighting.” But though the technology game - at least at the fundamental light source level - might be almost over, the politics had only just begun.

  8 Initially it was thought that combining the output of red, green, and blue LEDs would be the way to produce white light. But it proved unexpectedly tricky to improve the efficiency of green emitters. The chip industry quickly learned that it was simpler just to “pump” a yellow phosphor with light from a blue LED.

  C H A P T E R T H R E E

  Low Hanging Fruit H earings at the United States Senate’s Committee on Energy and Natural Resources had been characterized down the years by decorum and polite discussion. The committee was known for its tradition of bipartisanship, of working across party lines to establish national energy efficiency

  standards for electric appliances. Its modus operandi was to achieve consensus between lawmakers, environmental groups, consumer advocates, and appliance manufacturers. But on March 11, 2011 the genteel discourse in the high-ceilinged wood-panelled hearing room at the Dirksen Building on Capitol Hill was rudely interrupted, by an intemperate outburst from a Republican committee member named Rand Paul.

  The hearings had been convened to debate one of the provisions of the Energy Independence and Security Act. This was a Bush-era piece of legislation which among other things set new standards for the efficiency of light bulbs. The act had passed both houses in 2007 essentially unchallenged. Now, four years later, the junior senator from Kentucky was seething. Paul asserted that he had been insulted by the government’s intention, as he saw it, to tell him what kind of light bulb he should buy. In addition to being an assault on individual liberty, this was an affront to the very idea of a free marketplace, of freedom of choice, indeed of capitalism itself. “You busybodies always want to do something to tell us how we can live our lives better,” Paul snarled petulantly.

  Suddenly, unexpectedly, light bulbs had become a hot topic in Washington. They were, it seemed to many on the right of politics, an egregious symbol of the over-reach of big government. An out-of-control nanny state was apparently hell-bent on banning the incandescent bulb, and in so doing violating the inalienable right of citizens to choose how they lit their homes. Reluctant consumers would instead be required, it seemed, to purchase compact fluorescent lamps, those ugly little “squiggly pig-tailed” devices that gave off a ghoulish green light. Libertarians referred to CFLs contemptuously as “Gore bulbs.” It was an outrage.

  9 Another Tea Party favorite, Michelle Bachmann, went even further, calling it an affront to the memory of the light bulb’s inventor, Thomas Edison. It was, of course, nothing of the sort. The new rules, slated to come into effect on January 1 2012, were merely intended to raise the energy efficiency of devices. They would not ban the incandescent light bulb. They would merely bring the rest of the US into step with California, the nation’s largest state by population and its most progressive by legislation, which had already adopted stringent new performance standards for lighting. Nor was there any question of compelling people to buy the hated compact fluorescent lamps, or indeed any other technology for that matter. But, as a spokesman for electrical lighting manufacturers made clear to committee members, the industry had seen the writing on the wall. It was investing heavily in the new technology of LED light bulbs. If they wanted to see the future of lighting in action, members had only to look up. Its chairman, Jeff Bingaman, proudly pointed out that his was the first committee in Congress to have redone its hearing room so that it was totally lit by LED lighting, all American made LED lighting at that. But as the new standards began to roll out, confusion as to what would happen was rife. Why had lighting become such a contentious issue? Where had these new standards sprung from? To answer these questions, we must flash back more than forty years and examine goings-on in California, America’s laboratory for the development and deployment of new technology.

  It was late one Friday night in November 1973 at the physics department of the Radiation Laboratory in the hills high above the University of California Berkeley. Despite the fact that the occupants of the offices had mostly gone home, almost all of the building’s lights were still blazing. Meanwhile, down below in the town, cars were lining up round the block, their drivers impatiently waiting to buy gasoline. Since the imposition of the OPEC embargo the previous month, gas had had to be rationed. Brooding on the need to queue to fill up his little Fiat the following day, a thought struck Art Rosenfeld. Gas and light were equivalent: oil was a form of energy that could be burned to generate electricity. A professor of physics, Rosenfeld was accustomed to doing mental arithmetic. He quickly worked out that, by turning out the lights in the twenty-odd offices down the corridor on his way to the door, he could save more energy over the weekend than his car would consume. “That’s interesting,” Rosenfeld thought, “I can do that in about thirty seconds.”

  In fact, turning out the lights took him about an hour. The reason was that it was hard to get at the wall switches. The occupants had blithely covered them up with posters or stacked file cabinets and bookcases in front of them. Why should they care if the lights were left on all night? It wasn’t as if they were paying for the electricity. The only exceptions were one or two offices inhabited by visiting European scientists. By contrast with their American colleagues, the Europeans were painfully aware of the price of electricity. In European college towns, landlords of student lodgings obliged their tenants to feed coins into electricity meters. Run out of change and the lights would go out.

  Rosenfeld had himself learned the importance of frugality early in life. Born in Birmingham, Alabama, in 1926 he had been raised during the Great Depression. His father was an expert in the cultivation of sugar cane, a specialty that took the family to Egypt when Rosenfeld was just six years old. At the school he attended in Cairo, classroom lights were invariably extinguished when lessons ended. Later on, as a visiting scientist at CERN in Switzerland and particle accelerator laboratories elsewhere, Rosenfeld had noted how Europeans were much more conscientious in their use of energy. And yet, despite the high price of electricity, European lifestyles were almost as good as American ones. In the US, by contrast, electricity was dirt cheap. As a consequence, Rosenfeld would often joke in later years, people treated it like dirt. Contemplating how hard it had been to switch off the lights in the physics building, Rosenfeld decided that the government’s approach to saving energy was hopelessly misguided. Gasoline lines and rationing weren’t going to solve the problem. “The cheapest energy,” he concluded, “is what you don’t use ... . It would be more profitable to attack our own wasteful energy use than to attack OPEC.” Something should be done. For Rosenfeld it was a revelation, in effect a light bulb moment.

  The following summer, together with his colleague and friend from Stanford Sam Berman, Rosenfeld convened a study group to examine options for raising the efficiency of energy usage in the US. The two physicists made a dynamic duo. Both boasted exceptiona
lly high-powered pedigrees. At the University of Chicago Rosenfeld had been the last grad student mentored by Enrico Fermi, builder of the world’s first nuclear reactor. For his part, Berman had been one of the few post-docs at Caltech selected for tutoring by the legendary Richard Feynman. Like Feynman, Berman had charisma. “Sam’s one of those people where, you go into a room and, almost saying nothing, he’s the center of the room,” one former colleague recalled admiringly. By the end of the study group’s first week the pair had calculated that the US economy was running at just ten percent energy efficiency. That meant huge savings could be made. Society uses energy mostly in three sectors: transportation, industry, and buildings. In transportation, Congress was going to set fuel-economy standards; industry was cost-conscious and had engineers to address the problem. That left buildings as the sector needing most help to improve efficiency. One of the most obvious ways to save energy in buildings - the low hanging fruit - was lighting.

  “We began looking at some things that were all sort of common sense,” Rosenfeld recalled. “Change incandescent lights to fluorescents, make better use of skylights ... that kind of thing.” It had long been known that driving fluorescent lamps at high frequencies would use much less electricity. What no-one had figured out was how to achieve this in a way that was both technologically feasible and commercially viable. In 1976 Rosenfeld formed an energy-efficient buildings program at Lawrence Berkeley National Laboratory. Berman bravely resigned his tenured professorship at Stanford and moved across the Bay to head the new group. The first problem the group’s lighting researchers set out to tackle was improving the efficiency of the fluorescent tube.

  Fluorescent lamps had made their commercial debut at the New York World’s Fair way back in 1939. The technology had been a long time coming. In retrospect, it is not hard to see why. Scientists had been tinkering with fluorescent lighting since the mid nineteenth century. Thomas Edison himself had been briefly distracted by the concept. An ofttold industry joke went that, had Edison invented the fluorescent lamp first, the incandescent lamp would have come along as a great improvement. The reason is that incandescent lamps are relatively simple: pass an electric current through a filament and it glows brightly. Fluorescent lamps are by contrast intrinsically complex. They create light via a two-step process. All fluorescent lamps consist of a glass tube which contains mercury vapor. Injecting an electric current into the tube stimulates the mercury atoms into discharging particles of light, known as photons. The ultraviolet photons strike the chemical phosphors that coat the inside of the tube, causing them to fluoresce, that is, emit visible light. To regulate their function, fluorescent lamps depend on an auxiliary device known as a ballast. This acts as an electrical anchor to limit the amount of current injected. The ballast keeps the current constant to prevent the lamp from self-destructing. Manufacturers considered this extra piece of kit a necessary evil.

  The first fluorescent lamps were intended for use as decoration, a replacement for neon lights. The tubes came in a variety of colors, including red, pink, blue, green, and gold. GE initially had no idea that the technology would appeal to a wider market. The tubes were after all large and needed a big housing to support them. Pretty soon, however, it was realized that the plain-vanilla white fluorescent lamps were more than four times as efficient as incandescents and lasted far longer. True, the light the tubes produced was cold compared to the warm glow of an Edison bulb. It was in fact a harsh white tinted with ghoulish green. Poor color rendering ruled fluorescents out of most uses in homes. But for owners of commercial and industrial buildings, the economic advantage of tubes was (and would remain) compelling. The initial commercial application for white fluorescent tubes was in railroad passenger cars. Soon, the fluorescent lamp was having a dramatic effect elsewhere, too. Especially in places where more light was desperately needed, like large offices and factory assembly lines. The market for tubes took off. By the early 1950s, sales of fluorescents had overtaken those of filament bulbs. By the mid seventies, when Berman’s researchers began their work at Berkeley, fluorescents were producing two thirds of all lighting in the US.

  Back in the late 1940s, experiments at GE’s Nela Park laboratories in Cleveland, Ohio, had shown that increasing the frequency of the electricity used to drive the lamps above the sixty-hertz mains current would improve their energy efficiency by as much as thirty percent. Jacking up the frequency would also eliminate other undesirable attributes. Early fluorescent ballasts were simple coils wound around magnetic cores. At sixty hertz they tended to buzz and hum irritatingly. Fluorescent lamps also had a tendency to flicker, which in sensitive individuals could trigger migraines or even epileptic fits. Boosting the frequency of the current up to twenty kilohertz would lift the noise above the range of the human ear. It would also eliminate the risk of headaches and seizures. But until devices such as power transistors became affordable, frequency conversion was simply not practicable. In the 1950s electricity was selling for a few cents a kilowatt hour, while a single transistor could cost tens of dollars. Soon, however, as production volumes increased, economies of scale kicked in. As in other applications, the coming of semiconductors transformed the nature of the game. Lighting was going electronic. But not without rearguard action from recalcitrant lighting manufacturers. Though higher efficiency would greatly reduce the running cost of their products, makers persisted in evaluating lighting fixtures based on their initial purchase price.

  Art Rosenfeld was just one of many whose minds were concentrated by the first oil crisis. A few miles east of Berkeley, in the little town of Danville, Carlile “Steve” Stevens, a Stanford-trained physicist, was also stimulated by the OPEC embargo into girding his loins. “OK,” he told himself, “I’ve gotta find something that saves energy.” Stevens designed and built one of the first electronic ballasts for fluorescents. Better still, it was a dimming ballast, one that could automatically modulate the light output by the tube according to the amount of ambient sunlight. And that was remarkable, because conventional wisdom claimed that it was not possible to dim a fluorescent light, at least not without causing unacceptable flicker.

  Born in California in 1931, Carlile Stevens is an all-American archetype, a compulsive inventor-entrepreneur. Over a long career, he has more than fifty patents issued to his name. His can-do motto: “I seek needs and I get ‘em done.” As a boy, Stevens manifested the classic signs of the born engineer. Give him a new toy and he would take it apart before playing with it. “Then I would put it back together and it still worked — but my mom said there were parts left over,” he recalled laughing. During vacations, to earn money to pay his tuition at Stanford, Stevens performed at county fairs as a human torch. He would pass two million volts of electricity over his body, brandishing a wooden plank that would burst into flames, like a light saber.

  On graduation, Stevens formed his first company. It made nuclear batteries used to power weather stations in remote locations like the North Pole. At the time, the auto industry was beginning a transition from mechanical ignitions to more efficient electronic systems. “I noticed there was stuff missing out of the stock room, and I ended up realizing that everybody was building transistor ignition systems. So I called them all together and said, Look, I’m tired of losing all this stock — I’ve designed an ignition better than this circuit that’s been copied out of Popular Science. We’ll build a hundred of ‘em, you can pay in cost, and then we can get back to work. By the time we’d built a hundred, we’d sold two hundred; by the time we’d built two hundred, we’d sold a thousand. Pretty soon we were in the transistor ignition business.”

  From transistorized ignitions, Stevens moved into computerized traffic control systems. In 1974, while working on ways of improving the brightness of traffic signals, he came up with his idea for a flicker-free electronic dimming ballast for fluorescent lamps. Stevens’ original plan had been to sell the ballast to Columbia Lighting, a large manufacturer of fluorescent fixtures. A contract was signed the
n cancelled after Sylvania, Columbia’s parent company, objected. The lamp-maker maintained a strict policy of eschewing anything that was “not-invented-here.” That left Stevens with a product and nobody to sell it to. In desperation, he made an unsolicited proposal to the Department of Energy in Washington. At any other time, this would have been a last-ditch, hail-Mary gambit. The DoE and its predecessor, the Atomic Energy Commission, had hitherto concerned themselves with energy generation only. That mostly meant nuclear reactors. The whole idea of energy efficiency was alien to the agency. But though a difficult concept for hard-liners to swallow, it was one whose time had come.

  In 1976, largely as a result of Art Rosenfeld’s urgings (like many high-energy physicists, Rosenfeld was also an adroit politician) the DoE established a Center for Building Science to investigate ways of saving energy. It would be housed at the agency’s Lawrence Berkeley National Laboratory, perched on a hilltop high above the UCB campus. The new center included the lighting group led by Sam Berman. Inspired by Stevens’s working prototype, the development of an electronic ballast would be the first challenge the center addressed. A request for proposals was issued. Twelve bids came in from small entrepreneurial firms. They included one from a bemused Stevens, who found himself obliged to bid on his own suggestion. There were two winners, Stevens’s company and Iota, a Phoenix-based startup. “The crazy part about it was, [the DoE] gave the lab four times as much money as we had asked for, then gave us less than we asked for to do the job — which is typical government,” Stevens observed wryly. Nonetheless, having the backing of a national laboratory conferred instant credibility on his invention, for which decades later Stevens remained grateful. “Sam’s a very smart guy, knew what he was doing, pulled the right people together. He helped us immensely in terms of breaking through all kinds of barriers.” None of the major US manufacturers of conventional, magnetic ballasts responded to the center’s request. In fact, the makers were actively hostile to anything that threatened their existing business. To discourage activity, they went so far as to spread rumors that electronic ballasts might cause heart failure in people with pacemakers. Characteristic behavior from an industry that was nothing if not adverse to innovation.