Story 2016-04-20 1B4TB More efficient new LEDs now available, over 200lm/W

More efficient new LEDs now available, over 200lm/W

in hardware on (#1B4TB)
story imageCree's newly announced XP-G3 model of LED delivers 31% more lumens (lm) and 8% higher lm/W than its predecessor. Offering over 205 lm/W at 350mA, this marks the first time commercially-available LEDs have exceed the efficiency of low-pressure sodium lamps, commonly found in municipal streetlights. OrangeTeK has already announced they are designing a new model of streetlight with XP-G3 LEDs. In practice, however, it's likely that most users of XP-G3 LEDs will run them at higher power with reduced efficiency, rather than install five times as many LEDs, due to price. Any efficiency improvements are good news, however, as numerous cities have already installed LED streetlights, and many more have plans in the works. This seems to be motivated by the whiter appearance of LEDs compared to sodium lights, which is ironically the major source of opposition from the public, who complain about LED streetlights keeping them up at night, among other concerns.

Philips had previously demonstrated 200lm/W LEDs, and claimed they'd be available to consumers by 2015, but a search of current products only reveals far less-efficient models. The XP-G3 is available for order right now. Cree has previously demonstrated LEDs in the lab that deliver up to 303 lm/W, which is half-way to the maximum theoretical efficiency of this technology. Estimates are that as much as one quarter of the world's electrical consumption is used for lighting. Most consumers could see significant savings just by switching to florescent or LED lights in the first place. About 50 percent of lights sold in the US are halogen incandescents, which are only one quarter as efficient as LEDs, have far shorter operational lifetimes, and cost about one quarter as much.
Reply 11 comments

Motives (Score: 1)

by on 2016-04-20 09:52 (#1B510)

I remember reading two scientific papers about this, one was about significantly increasing visibility around dusk and dawn, when the sodium lights are not very efficient (illumination-wise, not energy-wise) It could, for instance, help reduces accidents at pedestrian street-crossing. The other sounded less scientific and tried to show a decrease in crimes when using whiter lamps.

And I've heard so many times the argument "LED consume less energy" touted that I actually believed LED were much more efficient than sodium lights already. Could it be possible that the people ordering all new lights to be LEDs incorrectly assume the same?

Re: Motives (Score: 1)

by on 2016-04-20 11:13 (#1B574)

There are innumerable (not very reliable) sources which spout that LED streetlights are more efficient. Obviously that's not based on facts. The information likely comes from the companies wishing to sell their new products, and it appears they come up with the claim in part by somehow comparing LEDs to non-LPS street lights, which are really only used in a tiny fraction of circumstances, where more color accurate light is required. In addition, they seem to use more-focused optics in new LED streetlights to compare to unfocused LPS lights, and generate more desirable numbers that way. They often also tout how much energy can be saved by enabling a motion-detection mode, which LPS isn't suited to, but I'm not aware of any municipalities who have done so, as there are significant practical drawbacks.

The comparison can get a little bit more confusing because LPS lights dim a bit over their lifetime, so slightly weaker efficiency numbers can be determined if one is so inclined. But as for reliable sources, the best I've heard is that, with twice the longevity of LPS, the reduced maintenance costs of LEDs can make up for their higher up front costs.

But back to your question... I have no doubt many people believe that LED streetlights are more energy efficient than existing LPS lights. BUT I would certainly expect much better of civil engineers, and due diligence from even non technical personnel. They merely need to compare the listed specs like power consumption, between the various options, before recommending or approving a major purchase... But feel-good measures, and green-washing, are sadly all-too common.

Re: Motives (Score: 1)

by on 2016-04-20 16:48 (#1B6GQ)

Even for household applications, compact fluorescent bulbs often have a higher efficiency rating (in terms of Lumens per Watt) than LEDs. However, LED bulbs are pretty close, especially when compared to incandescent, and are still improving. Add in the instant startup, the more focused output, and the whole no-mercury thing, and it's no wonder why the new LED technology is quickly becoming the new "green" favorite.

Re: Motives (Score: 3, Informative)

by on 2016-04-21 05:49 (#1B8H1)

Actually, LED bulbs handily surpassed CFLs years ago. Now a 60w equivalent (800lm) LED uses 9w, while CFLs never got better than 13w for the same output. That's 30% more efficient.

Note that I'm using the inexpensive $1.75 generic Lowes LED bulbs (60w equiv) with 2-yr warranties, for reference. There certainly are still less-efficient older LED bulbs on the market, as well as some that are more-efficient.

40w equiv (6w) LEDs are similarly inexpensive and more-efficient than their CFL counterparts.

However, what I like most about LEDs is that they work great at even lower power levels, too. CFLs below 40w were candelabra base with long, slow warm-up times and relatively poorer efficiency. Similarly, incandesent efficiency was on a curve, so 60W bulbs had DOUBLE the lumens output of a 40W bulb. But with LEDs you really can scale that down as far as you want. No longer is a 40w bulb the lowest-power practical choice for smaller rooms, closets, etc.

It also helps greatly that LEDs do fine in the cold, and can be switched off/on almost unlimited times, making them a great optionin refrigerators, motion sensors, etc., where CFLs don't really work at all. After all, hot bulbs in your refrigerator is about the worst waste of electricity imaginable.

Great but (Score: 0)

by Anonymous Coward on 2016-04-22 04:48 (#1BCH5)

We have a long way to go. It is an improvement that one light in the circuit doesn't blow the rest. That one socket can be replaced without affecting the others. The power config isn't good. Turning the light switch off doesn't actually turn off the power. Which can lead to current running through you if you change a bulb with the lightswitch off. That did not hurt, but it wasn't good. Then we have the problem of cost: 1 power cord per light is an upfront cost that can be borne, but the cost of replacing the power packs every couple of years adds up. I remember buying cheap ass $1 light bulbs for years and replacing them without hassle. Going through putting out the whole socket and buying a new transforming for every light in the house is starting to seriously piss me off. The way they churn through bulbs is a concern. The cost of the bulbs is a concern at what? $5 to $25 a bulb? Geez. That hurts. This room has 8 of them in the ceiling. Start multiplying. Yes, it is an improvement over halogen which quite frankly was a secondary heater in the house. There are still improvements to be made. One of them is not using springs with so much tension that they rip through the ceiling plasterboard when the socket is pulled down.

Re: Great but (Score: 0)

by Anonymous Coward on 2016-04-22 08:06 (#1BCZA) LED bulbs have a ten year replacement warranty. My CFLs and incandescents did not.

Re: Great but (Score: 3, Insightful)

by on 2016-04-22 08:31 (#1BD0F)

You can get CFLs and LEDs for $1, and screw them into the same E27 / A19 fixtures your old lightbulbs used. If you've opted for different fixtures and bulbs, which don't work well, that was your own mistake, and irrelevant to the lighting technology. I expect most people were smart enough to avoid that trap.

Re: Great but (Score: 0)

by Anonymous Coward on 2016-04-22 15:30 (#1BEBV)

After 5 different types of transformer and trying every led globe type and paying an electrician to prove it isn't the mains power I am done with this technology.

Re: Great but (Score: 0)

by Anonymous Coward on 2016-04-27 12:16 (#1BZ1E)

Sounds like candles and olive oil lamps might be your best bet.

You still haven't explained to anybody how you can turn your switch off yet still have power running to your LED bulbs. That would happen regardless of what kind of bulb you have in there, unless your LED bulbs are powered by some kind of magic.

Re: Great but (Score: 0)

by Anonymous Coward on 2016-04-22 13:32 (#1BDYF)

I have no fucking clue what you're talking about. Can you try again in complete sentences?

Re: Great but (Score: 3, Informative)

by on 2016-04-25 14:27 (#1BQ8Z)

If you still have power flowing after turning off the light switch you need to call an electrician. It's not a function of the bulb, you have either faulty wiring or a faulty switch.