Originally posted by: Sphexi
There was an estimate that if all of the households in Canada switched to CFLs, it would save enough electricity to power a city of 100K people for a solid year. If all of North America did it, it could power a city of a million for a year. That's a decent amount of power saved, quite a few power plants that could be shut down.
No idea about street lighting, although there probably aren't nearly as many as there are lights in houses, I'm betting they draw more power, so perhaps the savings would be about the same? Different technology though, so I doubt it applies.
Saving the power demands of a city of a million = quite a few power plants?
While very gradually replacing the high pressure sodium lamps with piles of LED's (as the lamps failed) would save some energy, simply removing a perfectly good high pressure sodium lamp and replacing it with and LED would actually increase the power demands: LED's just don't grow on trees; it takes energy to make them. It'd be like tearing a house down and rebuilding it so you could squeeze in an extra half inch of insulation. (shot in the dark approximation)
Oh, also a consideration: in colder climates, particularly 2 story homes where the majority of lighting used is on the lower floor, the claim that energy is "saved" is exaggerated. The "wasted" energy of an incandescent bulb is heat - heat for your home. The only energy wasted (during the months you're heating your home) is the light that shines through your window to the outside. I probably should point out that in the big picture, this is true in homes that have electric heating. In homes with fossil fuel heating (coal, natural gas, propane, or oil), these fuels can be turned into heat at the home with far more efficiency than they can be converted to electricity at a power plant, and then sent to the home where they ultimately are changed back into heat.
i.e.
fossil fuel -> electricity -> home -> CFL bulb in a house with electric heat when it's cold outside: no energy is saved. The incandescent bulb's heat is not "wasted energy."
fossil fuel -> home -> heat;
small amount of fossil fuel -> electricity -> home -> CFL = saved energy. Not at the household level; the house uses just as much energy; but the inherent inefficiency of conversion of fossil fuels to electricity is where the savings occurs.
And, in my case,
3 tons of coal -> nice bright fire in the coal stove -> keeping my house at 75 to 80 degrees in the main living areas, cooler in the bedrooms for sleeping -> I can enjoy the nice warm glow of the fire and not turn on any lightbulbs in the room with the stove -> at a very small fraction of the cost to heat with any other fuel.
