Electrical Engineering/Power Saving
Do switching off lights could really save power on the whole. Like during "Earth Hour" or something, people will switch off lights for an hour or so. Actually power is generated all the time. If people stop using the power, the power generated will be wasted. Right? Consider a small town having 100 houses and a generating station. If all the houses stop using power of 60%-70% stop using it. Will the power generated be wasted upto certain extent?(Because we've generated for 100 houses and only 30 in use).
But the power being produced is a function of the amount needed to supply the users. It is not static; the generator output produces the amount of power being drawn by the users. The fuel required - or power input to the generators - is directly proportional to the amount needed at the output. The generators of todays design are very efficient. They can convert the mechanical input or fuel input to near 100% efficiency at the output. Therefore, if the consumers reduce the amount of power they are using that translates into less fuel needed to feed the generators.
So, there is very little wasted power when the demand slows down. Of course, in the extreme case when power demand goes to zero the generators will need to keep spinning in readyness for when the demand picks up again. In that case the wasted power would be only what it takes to keep the generator spinning with no load - which is very little.
Good question. Hope this answers it for you.