It’s dwarfed by waste heat though, which is an estimated ~70% of all energy produced.
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It's a different problem altogether IMO. Wasted light is a design, political or education problem. Heat waste is often an engineering problem that we still haven't been able to solve.
Yes, it mostly is a different problem. My point is that with regard to energy wastage we have hugely more important issues than unnecessary light output. And the switch from incandescent light bulbs to LED has already reduced the energy wastage from lighting. I'm all in favor of reducing light pollution, but not because of energy concerns.
Unfortunately leds have made light pollution worse.
Instead of pocketing the difference in greater photon production efficiency the trend has been to just make things brighter.(where they really don't need to be)
Not to mention, not just lighting use, but lighting design needs a complete rethink in the age of leds. Much nighttime lighting, public and private used to cast a nice, pleasant glow, now very often led nighttime lighting is far too bright, and produced in wavelengths that can be quite unpleasant on the eyes, and registers as cold, sterile, and unnatural.
The problem of light pollution is not solely about energy wastefulness. Light pollution disrupts natural rhythms and ecosystems. The blotting out of the night sky is a great loss for the human soul and human experience.
> Unfortunately leds have made light pollution worse.
They also do an end run around the legal efforts to contain or limit light pollution.
In my state, we have the Dark Skies Act which tries to limit the amount of light pollution in certain areas, but it largely hasn't been updated for the use of LEDs. Some counties now define light output based on lumens, but the law AFAIK still references wattage limits. So, new lights that, under the intent of the law, are too bright and require shielding can probably skirt around it (IANAL).
But, almost no one knows about it, so enforcement is spotty at best.
(I'm slightly annoyed presently, because some new neighbors installed a floodlight that's pointed directly at my bedroom from across the valley and it doesn't appear to be doing anything useful. Stargazing and amateur astronomy is going to suck this summer.)
When it comes to bright outdoor lights, high fences make good neighbors. I have a neighbor that leaves their wide angle floodlights on all night in the backyard, some of which are directly pointed towards our shared fence. That is less of a problem now that I have a block wall that may(not) be just a bit too tall for local code but makes my backyard very dark.
That is mainly a choice of the installer, you can get LED lighting in 2700K. It's a regulation update to insist outdoor night time public lighting be 2700K or lower.
The sweet spot for lumens per watt is about 5000K I think, so there is also a power efficiency angle which is probably why a lot of these new lights are way too blue.
> Instead of pocketing the difference in greater photon production efficiency the trend has been to just make things brighter.(where they really don't need to be)
Are you saying that people are replacing, say, 100W bulbs with LEDs consuming 100W? I find that hard to believe, given that LEDs emit the same amount of light at approximately 1/10 the wattage. That would mean we're replacing 100W of incandescent bulbs with 1000W equivalent of LEDs? Or, is this versus fluorescent, which would be more of a 1.5-2:1 wattage equivalent exchange rate?
As for LEDs being "cold, sterile, and unnatural," that seems to be primarily a property of older LED bulbs. Newer bulbs are perfectly capable of emitting light at virtually any color temperature between 3000-6500K, which encompasses everything from "soft white" to daylight. Personally, I prefer daylight balanced bulbs, because I do some color sensitive work, and those bulbs have the highest available CRI of any non-incandescent bulb, but many people do prefer the "soft white" style. Even for non-color sensitive work, I find them too yellow for my liking, but I get that this is all down to personal preference.
GP subject Street Lamps / Lanterns.
Sodium vapor lights were the common lighting mode through the early 2000s and have a soft warm orange glow that was somewhat soothing.
The new LED street / parking lot lights are high color temperature 'daylight' style stadium lights, and have not had improved diffusers or reductions in effective lumen output. Many who don't have to spend time near these lights see it as an anti-crime benefit and ignore all other social costs.
Heat production is a necessary component of all energy transformations. Nothing is 100% efficient in this regard as you know.
But light pollution, while producing waste heat, is also just unnecessary in general.
We don't need to keep office buildings lit all night, we don't need to have cities lit up all night like sports fields. Night time lighting should be on a targeted and as needed basis.