I was told that coal fired electricity generators do not 'throttle down' at night so a lot of power is wasted

Question

This is according to a friend who works for a power company - apparently it is not practical to cut the output at night, even though demand is much lower. However if that is the case electric cars could be charged at night when demand is low, at no additional cost in terms of pollution or capacity requirements. What do others think?

Answer 1

You are right. I used to work for a contractor of an energy company and that is true. energy can not be stored as easy as water for instance, so it is very much lost. But it is very expensive to shut down one of these big generators. To re-start them may take several days. The shutdowns are normally plan way ahead of schedule and the planning for that may take months. Of course, it also depends in the size of the generator; but for the most part that is the case.

Answer 2

Electrical generation does actually throttle down at night if the amount of electricity needed is less than during the day.

If you cut the output at night, there isn't anything electrical that would work so we need to keep generating 24 hours a day. You can pay more at peak periods where the demand is greater and companies may offer incentives to use electricity at different times than peak periods.

During power shortages, Southern California was producing 600 Megawatts per hour to provide electricity for air conditioning in buildings during heat waves. As soon as the demand became greater than amount generated, then we have power shortages and rolling brown outs.

In regards to electric cars, they need power generation to recharge the batteries and that will generate GHG emissions.

Lessening consumption is the key to reducing emissions. Go to http://www.thermoguy.com/globalwarming-h... and see how California got knocked off the power grid treating the symptoms of heat waves.

Answer 3

they do not need to.

coal fired plant are not peaking generation plants

coal fired plants are mainstay plants.

they do throttle down if needed. (They can throttle down about 30%)

but this is seldom needed

wind power is wasted to as if you throttle down wind plants when you have wind you can not make power when you do not have wind but need the power.

hydro electric, gas turbine and geothermal can come on line fast so they are good peaking plants.

coal plants and nuke plants take time to bring on line so they are mainstay plants.

cars can be charged at night IF you have the mainstay plants

but if you have more demand at night you will need more mainstay plants.

so you will have more pollution even if you do not need more capacity because you will need to use more peaking power.

the amount of mainstay plants are set by minimum power needs.

we do not have the mainstay plants we need at this time. so most of the hydro plants are used as mainstay plants.

this is why the western US had a problem a few years ago.

as most of the lakes that fed these plants were low.

now they want to go CO2 free and the systems they want to use are not mainstay plants.

you can not rely on or use solar, wind or hydro as mainstay plants long term.

the only plants that you can rely on as mainstay plants are coal.or  gas boiler and nuke plants

so if you want to go CO2 free you will need many more nuke plants.

the global warming people will not tell you this because few of them have any idea how the electric power system even works in the US.

you can tell because the same people that block new hydro and nuke plants are the same people that scream the most about global warming.

THEY JUST DON'T UNDERSTAND.

Answer 4

You are right. This is why most electric companies vary their rates (night rates are cheaper). Now that there is a hybrid that gets 150 mpg, that would be the perfect time to plug them in.

Answer 5

Absolutely right.

One other thing that could take advantage of this would be giving people electric meters that charge less for electricity at night.  (Industries already have them in many places) In tests of these meters, people voluntarily started using more electricity for things like washing at night, rather than in the day.

Answer 6

Your friend doesn't know. Work that a motor can produce depends on the load. U can have a 40 hp motor but if the load isn't there u will not use that much power. If the coal furnace didn't cut back it would not be long before u tripper the over speed. Physics says that u cannot create or destroy energy. It may change and the efficiency might not be as good,but it is all tied together.