How to save 30% of the energy used in outdoor lighting!

We could save literally MOUNTAINS worth of coal every year if we just enacted a law requiring one simple thing.

If you have ever flown, you know how pretty cities look at night. All of those pretty lights twinkling down there! But think for a moment; All of that light, other than giving you a nice vista, is totally wasted. It goes off into Space.

Studies show that most outdoor lighting fixtures send about 30% of their light into space, and not to the ground where we are and where the things we want illuminated are.

We need to convince some Congressman to draft a law requiring that all new or replacement lighting fixtures henceforth radiate no more than 1% of their light at an angle above the astronomical horizon, with exceptions made for sports stadiums and railroad yards were such a requirement would be difficult to comply with.

The slight extra cost of such fixtures would be recovered by their owners quickly by being able to use less wattage for the same amount of effective illumination.

And maybe, just maybe, people in the cities would be able to see stars again!

getting some decent laws passed!!!

Something like 40% of the energy used to make the light is wasted because it is converted into heat. If you want to make a big difference then replace the bulbs with LED light bulbs or fluorescent light bulbs. They have already started replacing blown bulbs in stop lights with the new LEDs here in Alabama. They just need to start on the lamp posts....

But FAR more expensive to implement!

rather than just the bulbs?

That cost will come down.

Also I am talking only new or replacement fixtures, not existing ones. The change would be gradual.

Astronomers love them because their monochromatic light is easy to filter out. Unfortunately they make everything yellow-orange.

High pressure sodium lights, the orange lights you see most commonly, have a wider less spooky spectrum, but are much worse for astronomy. They are 40-50% efficient.

LEDs are still much too expensive for street lighting -- last I looked they were $20-25 a watt. Replacing sodium vapor street lights with LEDs might cost a thousand dollars per fixture.

Currently all the lighting, interior and exterior, in my own house is compact fluorescent, but I'm thinking seriously about installing LED lights for certain task lighting. White LED's are great for moving around the house in the dark of the night. The light white LEDs make is very much like moonlight or starlight, which is probably very good for one's natural biological rhythms.

we need to keep the feds out of state matters

saving nighttime electricity, is going to be a hard sell
politically, any laws would piss off a few people,
without making any friends, you don't already have

One group is the International Dark Sky Association: www.darksky.org

Don't admit that your goal is dark skies! Sell this as a means of reducing fossil fuel use and emissions! Sell this as a savings in municipal and commercial costs!

If they think you have a nerdy agenda (and we telescope makers are nerds) they will never, ever listen to the rest of the article.

and efficiency. But they do have some successes in certain towns; they've been at it for a while. (Admittedly, they have the most success in towns near major research observatories.)

In the meanwhile, we can use a "light pollution reduction device." In the olden days, that was a euphemism for a slingshot. But nowadays, that's more likely to be a laser pointer, which will turn off a street light if you shine it on its photoelectric daylight sensor.

Can work wonders. And it comes off next time it rains.

How much energy is spent on street lighting? And do we really need it?

As the big power plants ramp up to turn out electricity in the morning and ramp down at night when people are sleeping, the machinery gets harder and harder to change from ramp up to ramp down. So, the power companies convinced cities, etc. to put in street lights so they could keep the plants running all night and produce revenue.

That points out the key problem with big centralized power plants; they are more efficient running at top speed. By using alternatives to fill in the peak demands, fewer big plants would need to be running to supply the base load. So less GHG emmisions would ensue.

Also, would it be such a bad thing for street lights to turn off from say 1am to 5am? We could easily do that, and especially if they ran on battery banks supplied by daytime solar.

Any reduction in GHG would be a plus, and renewables could quickly fill in the peaks.

One advantage in streetlights is they do reduce crime and improve safety: If we, as a species, are likely to get our fat arses out of the car and start walking, streetlights would play an even larger role in getting us to our destination in one piece, even at 1AM (in fact, especially at 1AM :beer:).

Incidentally, whilst I'm sure power co's pushed for electric lighting, streetlights did start out as gas lanterns way before Edison. Using coal gas, no less, so we're already cut down the CO2 output... :silly:

Is there a need for anyone to be out and about at 1am. Or even after 9 or 10pm. For most of history we have not been nocturnal.

why restrict people's rights if you don't have to?

Plus, the world keeps spinning 24h a day. Commerce happens at night - which is a nice thing, as it spreads the demands placed on our infrastructure, from traffic to electricity.

Those who feel a need to be out in the streets at all hours can carry their personnal light. Or invest in a pair of IR goggles.

Schools and most offices tend to work during the day, but a lot of production & distribution runs through the night - along with the attendant support services. People are clocking on & off and traveling constantly.

This is generally a good thing: If the entire night-shift world were moved to the day time, much of the baseline power generation would have to be moved into peak hours as well, exacerbating the problem. The saving made by not running streetlights would be lost in the overall chaos.

If what you say is true, then what we should be doing is rounding out the peak times by making people work all hours of the night and day.

If the problem is one of how to organize our lives to make our use of power more efficient, then we can and should do so?

Or, we can reorganize how the power is distributed to make the most efficient use of the power?

Much easier to manage the power, I'd say. And one way we do that is by putting a premium on peak use... something power companies have already tried.

The problem is partly one of waste, really. We can be more efficient, more economical. Just doing so would lower GHG by a fair percentage, starting tommorow.

What do you choose?

Most power generation methods are not affected by the day/night cycle: It's as likely to be as windy & wavey at night as it is during the day, and of course hydro, fossil & nuclear run around the clock anyway: Only solar (which also tends to be more expensive than the others) works to our current pattern. From a pure physics point of view, it would be easier to spread out our energy use evenly over the whole 24 hours than to store it (pumped hydro, fuel cells, flywheels, etc) and have to deal with the associated entropy.

The main problem with this is a socialogical one: most people, including myself, like the idea of doing a days work and then enjoying the evening: So whilst any power solution can be implemented by changing the laws of economics, a 24/7 society would involve changing the laws of human nature: No chance of that.

Some things - at least, at our current level of technology - just cannot be time shifted. Turn off an aluminium smelter at 5PM, and it will take you 2 days to get it restarted: Working purely 9-5, we'd never see aluminium again. or steel, copper, cars, some foods, premature babies... it's a long list.

Although I can't qualify it, I would hazard a guess that our current pattern of mainly day and some night working is the most effective one we're going to come up with. We can encourage people to be more efficient: the peak rate electricity surcharge is a good way of doing that - just as peak rate phone calls take pressure off the the communications grid - and I'd like to see a nice fat carbon tax in thier somewhere: but I think there is only so much scope for re-engineering ourselves.

I think streetlighting is way down the list. (Although as an amateur astronomer, I would like to see it reflected downwards!)

Think how much GHG are produced to fire up the street lights. We gotta start somewhere. Where would you start?

If we can't do societal changes, then the society will fail. Can we adapt? Or should we build more nukes, not adapt, and force the issue even further?

The CO2 from the morning commute dwarfs the output for street lights: Get people working from homeevery other day and they'll be happier, on time, and less polluting. It doesn't apply to manufacturing jobs, of course, but they're all in China anyway...

that an adolescent civilization would throw their light out into space. Exuberant, but wasteful. And maybe naive. A baby laughing in a forest populated by wolves.