60W of energy in order to produce 800 lumens (lm) of light – meaning that only 5 per cent of the energy input is actually converted into light.1 The remainder is lost as heat. The precise number of lightbulbs sold each year is unclear – some estimates run as high as 15bn – but few are recycled. “So, lightbulbs are an environmental disaster, a huge product mistake and an enormous waste of energy because they are engineered incorrectly,” summarises Sowden. “A disaster.” In 2008, the United States Department of Energy (DoE) militated against this situation with the launch of the L Prize, an international competition to create a design to replace the standard 60W incandescent in a bid to “spur lighting manufacturers to develop high-quality, high-efficiency solid-state lighting products to replace the common incandescent lightbulb”. The DoE offered $10m to the manufacturer of the first lightbulb that could deliver 910lm with an energy input of less than 10W, thereby transforming the L Prize into a kind of Millennium Prize for the lighting industry: a cash driver for rapid technological advance.2 In particular, the competition represented a potential springboard for LED lightbulbs, a technology that produces light by passing a voltage through a semiconductor to achieve electroluminescence. LED lightbulbs had been on the market since the early 2000s, but at the time of the L Prize the technology remained relatively niche and underdeveloped. “There were just a few LED bulbs on the market that could serve as a replacement for incandescents,” notes the DoE, “and most were 25-40W equivalents.” The only viable alternative to LEDs were (and remain) compact fluorescent bulbs (CFLs), which can produce around 800lm with an energy input of 15W, but which have to contain a small amount of toxic mercury in order to operate. The US Environmental Protection Agency’s advice should a CFL break in your home is stark: “Have people and pets leave the room.” In August 2011, the L Prize found its winner. Philips (Pynchon’s mad-dog disruptor) produced an LED bulb that could provide 910lm using only 9.7W, 1 A team at MIT are developing an incandescent that they hope will up this efficiency to 40 per cent. The device works by surrounding the filament with a crystal structure that bounces back the energy otherwise lost to the atmosphere as heat. 2 The Millennium Prize Problems are a series of seven mathematical problems stated by the Clay Mathematics Institute in 2000. A correct solution to any of the problems results in a $1m prize. Only one of the seven – the Poincaré conjecture – has been solved to date.
“Edison didn’t make his light look like a candle; he made it look the way it needed to. The lightbulb shape is fundamentally wrong for an LED.” an achievement that the DoE boasted led to energy savings of $51.3m in the first two years after the bulb’s commercial launch in 2012. Philips’s device became the first LED lightbulb that could compete on a level playing field with incandescents and the problem seemed solved. “But what wasn’t discussed was that the Philips LED bulb weighed around 200g, meaning that it required a huge amount of material to make,”3 says Sowden, pointing to the heavy metal collar required to dissipate the heat generated by the bulb’s circuitry and LEDs. “So you’re absolutely saving energy if you use that bulb, but at the manufacturing end they’re using a lot more energy to convert that mass of materials into a product.” The Philips bulb and its descendants require heavy heat sinks4 because the heat generated through the operation of the LEDs makes the device act as a micro-greenhouse. “Which is insane,” says Sowden. “You leave yourself with an engineering problem created solely by the fact that you’re trying to make it look like a lightbulb, and end up with a Sorcerer’s Apprentice situation of multiplying insanity. Edison didn’t make his light look like a candle; he made it look the way it needed to. This is a big accusation to make, but the lightbulb shape is fundamentally wrong for an LED.”5 So enters the Sowden Light: the LED lightbulb that isn’t a lightbulb. The design breaks down into 3 The original Edison bulbs weighed around 25g to 30g. 4 Contemporary LED bulbs are lighter, but remain reasonably heavy. The Philips E27 Edison Screw LED lightbulb, for instance, weighs 100g. 5 The lengths that lighting brands will go to in order to ameliorate this are striking. When Flos created an LED version of Gino Sarfatti’s 1968 Model 1095 lamp in 2013 – a design intended to work with an incandescent bulb – the company resorted to engineering an elaborate water-cooling system to prevent the LEDs from overheating. Sowden’s comment about insanity seems applicable.
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