LEDs promise brighter future, not necessarily greener

Aug 24, 2010

Solid-state lighting pioneers long have held that replacing the inefficient Edison light bulb with more efficient solid-state light-emitting devices (LEDs) would lower electrical usage worldwide, not only "greenly" decreasing the need for new power plants but even permitting some to be decommissioned.

But, in a paper published Thursday in the Journal of Physics D, leading researchers from Sandia National Laboratories argue for a shift in that view.

"Presented with the availability of cheaper , humans may use more of it, as has happened over recent centuries with remarkable consistency following other lighting innovations," said Sandia lead researcher Jeff Tsao. "That is, rather than functioning as an instrument of decreased , LEDs may be instead the next step in increasing human productivity and quality of life."

The assumption that energy production for lighting will decline as the efficiency of lighting increases is contraindicated by data starting with the year A.D. 1700 that shows use has remained a constant fraction of per capita gross domestic product as humanity moved from candle to oil to gas to electrical lighting. Thus the societal response to more efficient light production has been a preference to enjoy more light, rather than saving money and energy by keeping the amount of light produced a constant.

"Over the past three centuries, according to well-accepted studies from a range of sources, the world has spent about 0.72 percent of the world's per capita gross domestic product on artificial lighting," said Tsao. "This is so for England in 1700, in the underdeveloped world not on the grid and in the developed world using the most advanced lighting technologies. There may be little reason to expect a different future response from our species."

Far from an example of light gluttony, Tsao said, by increasing the amount of lit work space and bright time, individuals would enjoy the desirable outcome of increasing their creativity and the productivity of their society.

To the question of how much light is enough, says Tsao, no one yet has produced a gold standard for light saturation levels.

While artificial illumination is considerably better now than decades ago, the researchers write, "People might well choose higher illuminances than they do today, particularly to help mitigate losses in visual acuity in an aging world population." More easily available light also may help reduce seasonal depression brought on by the shorter darker days of winter, and help synchronize biological rhythms, called circadian, that affect human behavior day and night.

As for problems that could occur with too much light — from so-called 'light pollution' that bedevils astronomers to biological enzymes that operate better in darkness — Tsao has this to say: "This new generation of solid-state lighting, with our ability to digitally control it much more precisely in time and space, should enable us to preserve dark when we need it." There is no reason to fear, Tsao says, that advancing capabilities "will keep us perpetually bathed in light."

Another paper author, Sandia researcher Jerry Simmons points out, "More fuel-efficient cars don't necessarily mean we drive less; we may drive more. It's a tension between supply and demand. So, improvements in light-efficient technologies may not be enough to affect shortages and climate change. Enlightened policy decisions may be necessary to partner with the technologies to have big impacts."

Explore further: And so they beat on, flagella against the cantilever

More information: The paper is available to review for a month, according to the journal, at iopscience.iop.org/0022-3727/43/35/354001

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User comments : 14

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RenewableTigger
5 / 5 (1) Aug 24, 2010
This sounds completely wrong to me. Since a few decades ago, most people in industrialized countries have bathed themselves in all the light they've wanted and cared very little about the energy cost. Compared to other electrical loads, light is minimal and people know it.

Another point would be that the increased initial cost of purchasing LED lights for various tasks should be included in that magical 0.72%/Cap GDP. This would leave much less for the energy which seems to me to correlate with stable illumination levels from more efficient devices.
daqman
5 / 5 (2) Aug 24, 2010
This is one of those things that has had me bothered for a while. My electricity bill shows my daily consumption to be about 50 kWh and I've been trying to bring that down. I only need electric light for less than four hours per day. On average it goes dark here at about 7pm and I go to bed early. One 60 Watt incandescent bulb uses 0.25 kWh per day if used four hours per day, I have several lights on at any one time but I tend to switch them off when I move from room to room so it's not more than maybe six to eight bulbs in total. So I can't imagine, even with incandescent bulbs that more than 2% of my household consumption is from lighting. Add to that the fact that my kitchen lighting is LED and I swapped all my incandescents to compact fluorescent or LED and my lighting bill has to be significantly lower than 1% of the total.

The big money is to be saved by changing methods of household heating and cooling, refrigeration of food, heat for cooking and hot water.
reebs
4 / 5 (1) Aug 24, 2010
I think the authors are making a logical point about the lighting trend that accompanies the technology, but I am not convinced that we are currently on that trend. The advanced from candles to lamps and lamps to bulbs were drastic. They allowed for huge improvements in safety and placement of light, but the chance from incandescent and compact fluorescents to LEDS is minor. Additionally, lighting up more space is not really an issue, I can't think of a space inside or really outside in a city that isn't already lit up. I guess I don't see where the extra lighting it going to go.
jimbo92107
not rated yet Aug 24, 2010
This discounts efforts to make lighting more efficient through the use of sensors and timing devices. If nobody is inside a room, then a sensor can turn off the lights in that room. Same goes for traffic lights where there are no people or cars. The trick isn't just to make lights more efficient, but to make their use more effective.
ArtflDgr
not rated yet Aug 24, 2010
dagman,
on thing you should look into about CFL is about how much noise they make. that is, why would power companies want them? because you dont save as much as you think you save when you know how power is delivered. incandescent bulbs change the timing very little as the only coil in them is their filament.

so a cfl may save X percent of energy, but in reality its not saving that much in costs as the power company charges you for.

i am sure someone else will explain it better than me.

its kind of like real power wise you save 30% (not a real quantity, just example), but because the noise and way it changes the power, you only save 10% in payments.

the power companies like them because they save the real power costs, while charging higher to meet power that is never delivered.

and dont forget that in our open system the chinese lobbied to insure they are the almost monopoly supplier.

funny, the old lights has near zero enviro impact, the new ones distribute mercury

DamienS
5 / 5 (1) Aug 25, 2010
I agree with the basic premise of this article - more efficient lighting will lead to wider usage.

People that think that current lighting levels are already high and so there won't be that much more usage ignore the nature of the new lighting medium (LED) and what opportunities it offers over and above conventional lighting systems.

LEDs and quantum dot lighting systems can be fashioned into many forms so that you could have, say, your entire wall surface used as an soft illuminator, programmable to meed your moods. The sheer variety of such applications is absolutely huge once the technology becomes widely affordable.
T2Nav
not rated yet Aug 25, 2010
ArtflDgr,
- My CFL lights make no noise at all. I do wish they started up a second or two faster, but I'm willing to suck it up to save the dollars on electricity.
- My power company does not charge me for power not delivered. Your power company sounds like a very sneaky bunch.
- Lobbyists ensure, insurance companies insure.
- Please explain again what timing you are referring to in paragraph one. Have a parent help with capitalization and punctuation so your logic is easier to follow.
ClickHere
not rated yet Aug 25, 2010
My house has some CFLs and some incandescent. Lighting doesn't really matter a great deal though, the huge energy use comes from refrigerator at 230W x 24hrs a day and our reverse-cycle heater at 1.7kW 8 - 18hrs a day. Light is around 300W when everything is switched on, say maybe 3hrs a day.

Since it's not my house (renting) I can't do a lot to improve insulation apart from curtains. Some of the lights are on dimmers so I can't change them to CFLs - dimmables are available but last time I looked they were prohibitively expensive.

What amuses me most about all of this though, is that if I catch the train to work every day of the week I save more in fuel cost than my share of the electricity bill for that week (3 people in the house).

I stopped caring about leaving the lights on when I wasn't in the room for 20 minutes when I discovered turning CFLs on and off ruins their life expectancy, making them comparable to incandescent globes.
ClickHere
not rated yet Aug 25, 2010
Having sensors to turn the lights off when I'm not in the room isn't going to be a break through in reducing energy consumption. I think we're pretty much stuck where we are until someone comes up with something better than refrigeration technology for heating and cooling, or some other form of energy supply which results in heating / cooling / transport not contributing to pollution.

@DamienS I like the idea of illuminated walls, or even entire ceilings. I think that will become very popular if it becomes available, especially if it can easily be retrofitted and uses low voltage.

I think LED street lights have potential to save much larger amounts of electricity that home use. Also commercial / industrial lighting. There are presently about about 300 20W fluro lights on where I'm working for about 20 staff. 6kW! Crikey! My home lighting electricity consumption doesn't matter bees di#k.
softail
not rated yet Aug 25, 2010
Sorry ArtfDgr, but you have the "noise" problem backwards. The power companies can only charge you for the "real" power you use. They do not like items with low power factor which comes form devices that apear inductive (like CFLs) or capacitive. So if you can use high inductive loads or capacitive loads you get free electricty... sorta of. This is because they measure power by measuring voltage and current and multipling them to get power. if load is inductive the voltage and current don't line up and the result is much less then what is really used.

Those of you that don't think we are using more light, think about all the gagets that have indicatior lights or back lit LCDs or glow ing th edark night lights or power "ON" LEDS.....
softail
not rated yet Aug 25, 2010
I totally agree with "ClickHere", my lighting, entertainment and gaget use at home is about 2% of my electric bill. the rest is AC, heating, cooking and hot water.
By the way, where I work we have 520 40 watt fluro light on 24/7 for about 40 people that are there 40 hr per week. thats 14,976 KWHR per month for just lighting!!
knikiy
not rated yet Aug 25, 2010
"...by increasing the amount of lit work space and bright time, individuals would enjoy the desirable outcome of increasing their creativity and the productivity of their society."

I'm going to play neo-Luddite here and mention how extending daylight hours has shortened the time it takes humans to reach sexual maturity, also possibly wreaking havoc with our hormonal systems in other ways we have yet to fully understand. The question is, is there a point where burning the midnight oil achieves diminishing returns, if not undesirable results?
Jimbaloid
not rated yet Aug 27, 2010
I for one have noticed an increase in the use of 'decorative lighting' in the last decade that would seem to support this view. Specific examples would be the blue up-lighting on the outside walls of a home nearby. Concealed LED lighting in kitchens is very popular now, with light playing onto the floor and work surfaces, or onto, even into cupboards with semi-opaque doors, all clearly with an intention for near continuous use. Browse around an Ikea store and you'll find LED light playing out from strips installed behind televisions, shelving and so on.
knikiy
not rated yet Sep 09, 2010
light pollution & cancer:

http://www.physor...712.html