LONDON: Lighting for homes, offices, factories and outdoor locations like highways, airfields and sports stadiums used 700 Terrawatt-hours (TWh) of electricity, almost 19 percent of all US power consumption, in 2010.
Traditional incandescent light bulbs, fluorescent strip lights, compact fluorescent lamps (CFLs) and the high-pressure sodium lights along highways used nearly as much power as industrial customers (970 TWh), according to a recently published report by the US Department of Energy (“2010 US Lighting Market Characterization” Jan 2012).
Lighting demand is rising sharply. Excluding headlamps and other lights installed on cars and other vehicles, there were more than 8.2 billion lamps installed in the US at the end of 2010, up from under 7 billion in 2001, according to the Energy Department.
By far the largest number are fitted in homes, which accounted for 5.8 billion lamps. The average American home has more than 51 — including 9 in the bathrooms, 8 in the bedrooms, 6 each in the living rooms and kitchens and 1 in the basement.
The typical home light is only on for only 1.8 hours per day, compared with 11-13 hours for lamps in offices, factories and outside. But it is spectacularly inefficient.
Residential lighting accounts for just 8 percent of all light output (measured in lumens) but 23 percent of the electricity used. Home lamps generate just 19 lumens of light per watt, compared with 70 for lamps in schools, shops and hospitals.
Residential lighting is an odd mix: high-wattage (56W) low-efficiency incandescent bulbs (3.6 billion of them); low-wattage (16W) high-efficiency compact fluorescents (1.3 billion); and fluorescent strip lights (570 million averaging about 24W per lamp).
By contrast almost all lighting in schools, offices and factories is provided by strip lights, averaging 37-39W per lamp.
Cutting the amount of electricity used to illuminate US homes by phasing out incandescent lamps and replacing them with ones that use less electricity, comparable to the commercial and industrial sector, is one the largest and easiest ways to cut the combustion of fossil fuels to meet electricity demand.
The 2007 Energy Independence and Security Act (EISA), passed by Congress and signed by President George W Bush, directed the Department of Energy to establish minimum efficiency standards for common light bulbs that are roughly 25 percent below current levels (PL 110-140 Section 321(a)(3)).
In practice, incandescent bulbs cannot meet these tougher efficiency standards forcing change to different format. The result is that traditional 100W incandescent bulbs have been withdrawn from sale since the start of 2012, and 75W incandescents since the start of 2013. From Jan 1, 2014, traditional 60W and 40W bulbs are also scheduled to disappear.
By the middle of next year, most incandescent bulbs will have been withdrawn from sale, though there are exceptions for some specialist types of lighting.
The potential electricity savings are enormous as the installed base of incandescents is gradually replaced by compact fluorescents and possibly even more efficient lamps.
In 2010, the 3.6 billion residential incandescents consumed 136 TWh of electricity to produce 1,640 terra-lumen hours of light. By contrast, the 1.3 billion residential CFLs consumed just 15 TWh to produced 670 terra-lumen hours, using 11 percent of the power to produce 40 percent of the light.
If all incandescents are replaced by CFLs, power consumption would shrink by 100 TWh per year. When it is completed by the end of the decade, the shift to more efficient residential lighting could cut total US electricity demand up to 3 percent.
The switch from incandescent to CFL bulbs, which is effectively compulsory, has stirred intense hostility from some consumers and lawmakers.
Some object to any government attempt to interfere in the working of the market by imposing efficiency standards, though there is a long history of the federal government imposing efficiency standards dating back to the 1970s.
CFL and even more-efficient light-emitting diode (LED) lamps are substantially more expensive to purchase than the incandescent bulbs they replace, though the Department of Energy claims customers will save money because CFLs last longer and use less power.
“Most CFLs pay for themselves with the energy they save in less than 9 months,” according to the Department.
Another criticism is that CFL bulbs, especially the earliest generations, are slow to start up; many still take several minutes to reach full brightness.
The US Environmental Protection Agency and US Department of Energy have sought to address those concerns by prescribing performance requirements for CFLs under their Energy Star program. To quality for Energy Star accreditation, CFL bulbs must start in less than a second, and most much reach full brightness in under a minute.
The final set of criticisms centers around the poor quality of light from CFLs compared with incandescents. Compared with an incandescent bulb, CFLs typically render colors with only 75-80 percent of the same faithfulness to natural daylight. The relatively low color rendering index (CRI) of CFLs is the reason many users have complained about the harshness of fluorescent light (and why office and school lighting often seems very unnatural).
Compact fluorescents must achieve a CRI rating of at least 80 to qualify for Energy Star accreditation. That is better than the average CRI of 75 for commercial strip lights, but still far below the 100 CRI achieved by incandescents.
The enforced transition from incandescents to more efficient lamps in general use highlights both the advantages and drawbacks of using government regulation to drive improvements in energy efficiency.
It is unlikely consumers would have made the shift on their own, unless electricity prices had risen to punitive levels.
Energy efficient lighting will achieve significant reductions in electricity use (and associated burning of fossil fuels) for only a modest reduction in lighting quality and lighting services for most US households.
High sale prices for CFLs, LEDs and other forms of efficient lighting should gradually come down as output increases and the industry benefits from learning curve effects and competition.
But the bungled introduction of CFLs left many customers dissatisfied with the quality of the new lamps as a replacement for incandescents. Early advocates of CFLs (and other efficient lamps) prioritized making them as efficient as possible and gave insufficient thought to other aspects of lighting service such as quality.
Slow start up times, poor light quality and high purchase prices for some early CFLs tarred the reputation of CFL technology and energy standards more generally for some consumers and lawmakers.
When the Department of Energy announced manufacturer Philips Lighting North America had won its “Bright Tomorrow Lighting” prize for a super-efficient replacement for 60W incandescents that could achieve a light output of 150 lumens per watt, but the replacement would retail at $ 50, it was met with howls of derision.
The idea is not as crazy as it sounds. The lamps last a very long time. In a lab test, 200 sample Philips prize-winning LED lamps have been operating continuously for more than 20,000 hours (equivalent to 18 years of typical use at 3 hours per day) with no failures as of November 2012, and with average light output showing no reduction since the start of the test.
The winning bulb went on sale to coincide with Earth Day in 2012. Various state energy programs and power utilities have been offering discounts and rebates on the lamps to cut the price to a less-shocking $ 20 or so.
On balance, the potential energy savings from the shift to more efficient residential lighting are too big to forego. But environmentalists, lighting manufacturers and the government should have done a better job explaining the change and ensuring efficiency gains were balanced with concerns about light quality.
Further cost reductions and improvements in light quality will be essential to ensure the change is eventually seen as a win for customers as well as the environment.
— John Kemp is a Reuters market analyst. The views expressed are his own.
