Free .pdf from the National Academies Press:
Light Pollution Hurts Our Economy and Our Resources
Topic covered on this page include:
Light Pollution Costs Money, Wastes Energy and Resources
Saving energy also makes economic and political sense. The International Dark-Sky Association in Tucson, Arizona, an environmental group, estimates that one-third of all lighting in the U.S. is wasted, at an annual cost of about 30 million barrels of oil and 8.2 million tons of coal-a total of about U.S. $2 billion. That oil amounts to generating 14.1 million tons of CO2 per year into the atmosphere, which adds to the global warming problems and all the extra future expenses that will entail, all for light that we do not even fully use. What is all this light for anyway? Do people realy enjoy living under a smoggish orange/copper haze every night? Do they understand the health problems this causes? Do people really consider this to be progress?
A Frivolous Double Pollutant: Remember that
Leaving the lights on for no reason at all is not just sheer laziness, but is also expensive that New Your City is seeking to eliminate. This opinion video piece covers how each and every light adds up to a large budget woe. Every light that is left on and every electronic device left running costs money. Money and energy that instead could be used to do something useful.
A Lighting Cost Calculator - If you would like to calculate how much your lighting costs can be, you can try out this site at: Selene-NY.org. A variety of prices are defined for the New York area, however, you can put in your own cost per kilowatt-hour to better reflect your own usages. Not only do they calculate the cost of running your lightbulb for the year (including prices due to their burning out), they also add in a number of other calculations as well. The site also calculates the amount of pollutants given off, the needed amount of coal to be consumed to support your light, the number of trees that would need to be planted to consume your CO2 production, and others that may open your eyes to the true expense of the different types of light sources.
Many towns and cities are taking their own steps to reduce light pollution, such as the town of Ridgefield, CT. As reported in the Danbury News Times article, Ridgefield will reduce their lights around some school lots, at the old high school, and at their Parks and Recreation Center. Their savings are projected to be almost $7 thousand their 1st year. That savings is after the one-time $12,000 cost Northeast Utilities would charge the town for shutting off the unused poles. From then on, they'll save almost $19 thousand a year.
The European Union is also phasing out incandescent light bulbs in their effort to cut energy waste. According
Force, Energy and Power Basics -- What is a Newton, a Joule and a Watt?
In order to understand what a watt is, you first need to know what a
start this little at home exercise, you'l need 102 grams of mass. A 100 gram mass, like the kind used in a physics lab, is quite
good, just tape a small paper clip to it if you would. However, if you don't have such a mass, well, then you can use $4.05 in
spare change. Specifically, you'll need sixteen quarters and five pennies. (Yes, I did measure them out, and on average, this
comes out quite well for what we need to do here.) Next, either combine the coins into a paper coin sleave, like those that you
get from a bank, or just tape them together. This combined mass should approximately come out to be about 102 grams, if you weigh
it and if you find the result is too much then you can subtract a penny or two. The closer to 102 grams the better. Note that 102
grams is also 0.102 kilograms or just 0.102 kg, as a
Next you'll need to measure a meter's length. You may have a meter stick. If not, you can use a tape measure with metric measurements on it. Or you can measure off 100 cm if you have a simple basic "foot length" ruler with a metric measurements.
Okay now, to quantify a Newton for you, first just hold and feel the weight of the 102 g mass. Now, according
to Sir Issac Newton, a
Thus, the gravitational force on the mass you feel in your hand is the metric (specifically the
Next, we quantify a Joule. A Joule is the fundamental SI unit of measure for energy. It can be found
in many ways, but for our setup described above, it is easily found as
If you want to define half a Joule, lift your mass half the height of the meter stick or use the same height
but use half the mass. We know the energy is in the lifted mass, for if we drop the mass we know that it will make a loudish sound
when it reaches bottom, it may bounce and it may roll about for a bit. The energy to do all of that came from you lifting up the
mass and you got the energy from food you ate earlier. While force is a vector, meaning that it not only has a quantity but it
also has a direction to the way it acts, energy does not. Energy is just a quantity (also known as a
Finally, we can quantify the Watt. A Watt is the fundamental SI unit of measure for power, which is the rate at which energy is used or converted to other forms per time. Specifically, a Watt is a Joule's worth of energy used per second of time or just
Thus, every time you turn on a 70 Watt light bulb, that bulb uses 70 Joules of electrical energy to give you
the light that it does for each and every second that the lightbulb is on. Or instead of turning on the lightbulb, you could have
used that energy to lift 70 of those 102 gram masses the height of a meter. 70 of those masses weighs 15.708 pounds in the now
Consider an average's night's worth of electrical energy convertion for the 70 Watt light bulb. I use the
of electrical energy into radiant energy, both heat and light, and just about all of it unused. For it is highly unlikely that the light's owner will keep watch over what it is being illuminated all night long.
Now take a look at your electric bill. You'll note that you are billed according to how many kilowatt-hours
(its pronounced just as you read it:
Thus, for every kWh of energy that you used for the last month, you could have lifted 3.6 million of your test masses the height of a meter. That converts to a 360,000 kilogram mass or 792,000 pounds, which is almost the weight of a Boeing 747 widebody commercial airliner! That's a lot of lifting! Also note that the 70 W light bulb will almost consume, on average, an entire kWh worth of energy each and every night it is on.
Take another look at your electric bill. At what rate are you being billed for your electrical consumption?
Do you now think that you are being unfairly billed or is the pennies per kWh that the rates typically are a
Also, consider how many homes there are in America and then realize what a tremendous amount of energy we use during our daily lives. Add to that the number of streetlights, stadium or athletic field lights, uplights on buildings that the owners like to believe is so important, most of which no one is around to look at. Is all of that energy usage truly necessary?
The electrical costs of lighting increases linearly, as opposed to what people can or will appreciate about lighting. As a quick guide, just consider the electrical costs of lights alone. The lights often have a NEMA label on them that identifies their energy consumption rate and the type of lighting used. This NEMA label is 7.6 cm by 7.6 cm (3" by 3"), colored yellow for low pressure and high pressure sodium vapor lamps (LPS and HPS), red for metal halide lamps (MH) and blue for mercury vapor lamps (MV). The wattage numbers that they report are typically one tenth the actual wattages used. These simple calculations can be done for any type of light bulb. Thus, the numbers for residents:
* kWh per night = actual bulb wattage * (3600 sec / hour) * (12 hours (average) / night ) * (1 kWh / 3.6 MJ)
FPL rates streetlights according to different calculations than what they do for residents. Page 86, shows that they are also concerned with the maintenance of their luminaire hardware for the lights, not just its electrical costs. They state that the monthly rates are:
NOTE: their prices are subject to change. You should consult their latest pricing guides listed on their website. FPL deals with more light types, here I just chose those that FPL will newly install. They currently charge 2.718¢ / kWh for non-fuel charges. There are other costs as well, for the wood, concrete and fiberglass poles, and for the underground connecting wires.
Now, imagine a city that has 10,000 HPS streetlights rated at 200W each. Such a city will consume, by according to FPL's rates 880 MWh per month or 10.56 GWh per year. By their rates, the city will be charged $101,600 per month and $1,219,200 per year. A MWh is a megawatt-hour or a thousand kilowatt-hours, while a "GWh" is a gigawatt-hour, which is a million kilowatt-hours.
From a rough measurement I made of a picture, I found that the light projected directly upwards from a drop lens, cobrahead streetlight is about 24.4% of the total light that it emits. If so, then 24.4% of those 22,000 Lumens per light (or 53.68 million Lumens for our city) are wasted as uplight. The electrical costs for that wasted uplight is then $5,831.60 per month, or $69,979.20 per year of light that is never used, that interferes with our ability to see the stars, that interferes with the environment and that interupts sleep and impacts our health. (That's your tax dollars at work!) I'm certian that we have more than 100,000 streetlights in South Florida. Luckily, FPL states that it will replace damaged streetlights with shielded cutoff cobraheads. As all of its light is used in such shielded luminaires, less powerful bulbs are then needed. Hopefully, FPL will use the lower wattage bulbs in the replacement luminaires, too.
Next, consider old fashioned incandescent bulbs. At most, only 10% of the energy they use generates light, the remaining 90% of the energy is needed to get the central tungsten coil hot enough to glow. In fact, a tungsten filament incandescent light bulb generates its light by using 90% of its electrical energy to first heat the filament to 3683 Kelvin / 3410°C / 6,170°F, in order to, as a by product, make light. This incandescent glow is also known as blackbody radiation. Which is the same glow that comes from any metal that is hot enough to glow, such as electrical stove top burners seen below. Consider this when you light the intertior of your house with incandescent bulbs in South Florida. For not only will you consume more energy and pay more in electrical costs just get the luminiation of othr more efficient bulbs give, but then you will also then have to pay more for the air conditioning costs needed to remove that generated heat from your home after lighting it with these incandescent bulbs. This is an indirect cost of such bulbs that is not calculated into their efficiency ratings.
Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value.
Paris, France: The City of Light Has Choosen to Go Dark!
Lights out – France to force shops and offices to go dark overnight
by Katie Davies
Published: Wednesday, 30 January 2013 in theguardian.com.
French light pollution law is expected to save 250,000 tonnes of C02 a year.
Shops and offices throughout France will be forced to turn off their lights overnight in a bid to fight light pollution, the country's environment ministry has announced.
Under the new law, which went into effect on 1 July, lights in shop window displays will be turned off at 1am. Interior lights in offices and other non-residential buildings will have to be switched off an hour after the last employee leaves.
"I hoped the law would change attitudes in France and help the country become a pioneer in reducing light pollution."
Glare Light from Business can lead to a One-Upmanship War, Instead of More Business
Shown to the left is an outward pointing "security light" at a corner of a commercial, strip-retail building. There are more lights at the corners and some in the middle. Why are the lights outward pointing? This is an example of wasted energy and dazzling glare which can hide a criminal. How many dark spaces do you see in the photo that a criminal could hide in? When installing lights, one needs to be careful of whether or not people can see only the light or what is being lit.
Of course, no one light is the total source of the problem. However, each light not only directly contributes
to this epidemic, but each light also
See What's Lit, Not the Light.
The parking lot on the left exemplifies shielded lighting. Note how few lights are needed to illuminate the area and how it is done without glare.
Next, the photo on the right shows lights shining into the sky and creating painful glare. Just what is the business owner trying to achieve with this overly-lit lot -- blinded customers?? There are so many poorly aimed lights being used that they almost seem to be trying to out-compete each other rather than illuminate the lot.
Which lot do you think people will feel is more comfortable, more welcoming, and less oppressive to drive into?
Other examples are linked here.
In the following study, researchers from the Lighting Research Center at Rensselaer Polytechnic Institute considered that last question, when they used a gas station to learn that by reducing the glare caused by the lights that illuminate the gas pumps, the station's business increased. For a customer, glare light can truly be oppressive and un-welcoming, as the study demonstrates.
An Evaluation of Three Types of Gas Station Canopy Lighting -- December 28, 2001
P.R. Boyce, C.M. Hunter, and S.L. Vasconez
The authors evaluated the lighting under a Springfield, MA gas station canopy, owned by F. L. Roberts and Company, Inc., using three luminaire types. All three types had the same energy consumption. They considered photometric conditions, energy efficiency, the tendency of drivers to turn into the station, patron opinions, the opinions of a panel of community leaders, and gasoline sales. The evaluation was carried out between April 12 and May 11, 2001.
I.The original installation used drop-lens in a non-cutoff
luminaire. This produced lower illuminances under the canopy. As this widely used luminaire was advertised, it produced a lot of
external glare making the lamp is visible from far away, for
II.The second installation used flat-lens in a
full-cutoff luminaire. Admittedly, this installation would be most preferable to astronomers and environmentalists, for it
III.The last installation used a prismatic glass
droplens in a cutoff luminaire. This setup helped to eliminate more shadows under the canopy. The droplens extended 2.5 in.
below the canopy. While they did produce more measureable glare, the amount was tolerable and the lamps were not visible from far
Image Credits: the Lighting Research Center of Rensselaer Polytechnic Institute.
Better Sales: In opinion surveys, patrons noted little difference between the three lighting installations. However, the percentage of drivers turning in to the station and the mean number of gallons of gasoline sold daily increased immediately following the change of lighting from the original drop-lens, non-cutoff luminaires to the flat-lens, full-cutoff luminaires. The percentage changed again when the flat-lens were changed to the drop-lens, cutoff luminaires. These changes in drivers' behavior suggest that better directed lighting encourages drivers to use a gas station, but a more comprehensive study should be conducted to validate these findings. The next table showed the L.R.C.'s findings regarding this aspect. For the given time durations, it records the number of vehicles that passed the station, the number of vehicles that turned into the gas station, and the resulting percentage of the total number passing and turning in.
Glaring lights can generate negative, oppressed feelings in people. Why would any owner of a gas station or any other business venture want their business to be associated with such feelings? People are not moths. They are not mindlessly drawn to light just because its there. Don't treat them as such.
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