

Ask HN: Is it worth saving electricity at off-peak hours? - digamber_kamat

Power stations continue to generate electricity at a fixed rate isnt it? Say a 100MW power station that is facing a peak load of 110MW at say 1PM. It faces a load of 70MW at 7PM.<p>Are power stations designed to produce lesser power during off-peak timings? Or in case of hydro-power plants will it continue to generate 100MW ? then it does not make sense to save electricity at 7PM because the saved electricity can not be stored and used later it will be wasted any ways.
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byoung2
_Or in case of hydro-power plants will it continue to generate 100MW_

Usually hydroelectric plants are placed near a dam, so that during periods of
low demand, the dam can be partially closed to slow energy production, and
when demand increases, the dam can be opened again. A closed dam is
essentially an energy storage device. So it does make sense to conserve
electricity during off-peak hours, so that the power grid can store more
energy for peak hours.

For natural gas and coal plants, for maximum efficiency, the plants should run
at more or less a constant rate. This is similar to a car, which gets maximum
MPG during constant-speed driving. Since technology for storing electrical
energy isn't advanced enough at this point for mass scale storage (we're there
for phones and laptops, almost there for cars, but not houses or cities),
there is a lot more waste during off-peak times from these types of plants.
There are wacky plans to use plug-in hybrids to store energy overnight when
electricity demand is low, and feed it back into the grid during the day.

EDIT: here's a good Wikipedia article on it:
<http://en.wikipedia.org/wiki/Grid_energy_storage>

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cperciva
_Are power stations designed to produce lesser power during off-peak timings?_

Depends on the type of power station. Hydro plants are in the best position --
under normal conditions, they are limited by the amount of water in the
reservoir, so they can make power almost 100% fungible by cutting off the
water flow to some turbines.

