The problem with Earth Hour is this: everyone turns off their stuff for an hour, and energy use drops. Then the entire time zone turns their stuff back on, roughly at the same time, around 9:30. When you turn something on, a surge of energy is required to get things started, and this puts enormous strain on the energy grid.
Now, power producers are aware of this, and because power generation doesn't happen instantly, they tend to ramp up power production well ahead of 9:30pm, so that when everyone turns their stuff on, there won't be any brownouts or blackouts that could potentially damage equipment, or leave people in the dark and the cold.
What this means is that although people feel good because they've participated in this collective catharsis, very little energy is actually saved. Power producers end up creating more power at a time when normal energy usage is actually falling, because 9:30 is past the normal peak time of energy usage, in a typical weekend day.
Lighting also contributes only a small percentage of overall energy usage, and the combined effect is minimal.
If you really want to contribute and do something good, consider unplugging your home entertainment system after every time you use it. Over the course of a year, this will do substantially more for conserving energy than your participation in Earth Hour.
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We have not inherited the Earth from our parents, we have borrowed it from our children.
What a stupid idea. Earth hour.
