Street Lights and Energy Consumption

The wattage of the lamp can be designed as per the required illumination at that street light.We can take the particular wattage of lamp that can produce the sufficient Lux. We are preparing the street light estimates by considering the 250watt sodium vapour lamp, providing the lamps for the distance between the both is around 30M to 35M, on 10 to 11M poles succesfully. If we provide double arm poles the distance, hight of the pole are consider to caluculate the Lux.

What you need to do is to forget the wattage and look at the effectiveness of the fixture.Street lights and other lights put out a huge amount of light pollution into the night sky. If more fixtures were designed for more effective delivery to the road surface you could use less powerfull lamps and not have the light pollution problem. As an amature astromomer, I can say that urban light pollution is one of the biggest problems astronomers have. Lights blaze all night with no sane reason. If you could figure out a way to store that energy for the day time you wouldn't need nearly as much generating capacity. Go to lower wattage, more effective full cut off lighting. John

..also, goverments are the best authorities to realise/promulgate alterantive energy usage. Simple observation is enough to realise that next to nothing is done on such applications, e.g.:solar panels at each street light post.

Those lamps are used to regulate (and consume) the power output of high efficacy power generation systems. Typically those installations have a high latency.

The safety of our drivers is also impressively increasing.

In Belgium (approx 95% of the roads are lighted) we once tried to save energy by switching them off earlier and switching on later, the traffic accidents in this period went up dramatically, by stopping this policy the accident rate went down again.

Power saving comes after safety.

(ps batteries in each pole, nature would really appreciate it. The used lamps are very energy effective, you can't do better)

No one said to switch them off. I said that every watt must be used to its greatest effect by making sure it only reaches the targeted area. The more you do this, the less wattage you need, the more power you save.

Just curious, what is the actual, unspoken point behind your inquiry?

I must not have gotten enough sleep over the weekend, 'cause I'm in a wierd mood today.

The first thing to pop into my altered state-of-mind is that we could save billions of tons of fuel every year if we constructed a network of mirrors all over the earth to reflect sunlight all 'round the earth to use for steet lighting!

I seem to remember somebody trying to push this idea some years back. The only problem is that the mirrors need to be in a geostationary orbit so the lighting needs to be more citywide than street by street.

Fortunately the idea got shelved and I havn't heard anything about it for well over a decade now. Like the guest in post #2 I too am an amateur astronomer and light pollution is bad enough as it is without some lunatic trying t turn night into day with a bloody great mirror.

I envisioned something a little less obtrusive -- such as a ground-based light relay network: Suck off a little for local use and pass the rest on to the next station. Of course, the whole idea requires large collectors and focused reflectors to overcome attenuation by the atmosphere. Feasibility can be put to the test in a work of science fiction, if it hasn't already been done.

You can do it with glass fibers.

The idea is used to distribute the suns free light in buildings to places where there is no roof access possible.

Or to be able to light where it is absolute unthinkable to have electricity. (eg. EX Zone 0)

The cold light source for your microscope uses a light fiber too.

Clearly light pollution is a problem and is only getting worse as the population sprawl continues. And yes, better directional lighitng would help to reduce it. These lights are mostly high pressure sodium. In terms of energy consumption, the actual wattage varies based on the height of the pole and use of the light. Freeway lights may be higher wattage than rural road lights. I would guess an average wattage might be 200 watts or so.

However, we can reduce the energy consumption wiht the installaiton of induction lights. Generally, we are looking at 50-60% energy consumpiton for the same light output. The life of the lamp is 100,000 burn hours or 23 years of nighttime operation. The first cost is high but will pay itself back and then some in energy and maintenance.

http://www.philips.ca/About/News/Section-13081/article-2179.html

Some years ago we were looking to replace the red lights on top of cellular phone systems.

We looked into this induction lamps, but at the end we decided to go for LED.

The induction lamp was to expensive and with the LED system we could monitor the functionality (measuring the current)