View Single Post
Old 2009-04-29, 14:34   #11
6809 > 6502
Uncwilly's Avatar
Aug 2003
101×103 Posts

23×3×443 Posts

Originally Posted by mdettweiler View Post
Simple supply and demand--the demand for electricity goes down, but the power companies still have the same amount of supply, so they raise their prices to compensate for the lost revenue.
It is far more complex than that. "Peak power" is the most expensive and the supply is not fixed, nor is it all in the hands of "the power companies". Running a gas turbine generator is most efficient at the 70-80% total output range, it is very inefficient at the 90-100% range; thus less demand at peak times means cheaper power. Some of the other peak power schemes use off-peak power to store energy to be released during peak times, these include pumping water uphill at night to have it ready to generate hydropower in the afternoon and pressurizing underground cavities at off peak, so that it can be used to spin turbines at peak times.
The "power companies" both buy power from power producers and generate their own, some sources are cheaper to buy from/use than others. The user does not pay the cost of the specific source, rather some averaged price. If the more expensive sources can be idled, the over-all cost/KWh can go down. There would be job losses, etc., but the average bill will go down. Big power users at peak times could use more power more cheaply then too.

I know someone that is training as a power grid operator, the desicions of which plant to call on and for how much power is a big part of what they are learning.

Also, I personally visited a small town's power plant, where it is cheaper for them to be on stand by and buy power from a bigger company than to run their smaller GTG all of the time. They have become a peaker plant. But, because they are a small scale operation, they have no waste heat boilers to recapture more power. A bigger plant can have a multistage set up for the waste heat steam turbines to generate power that would otherwise go to waste.

Peak power is where it is at baby.

The power for PC's at night is almost free. This is the power that larger scale plants produce to stay on-line and warmed up. A big coal fired plant or nuke can't throttle up and down as eaily as a gas fired plant can, but nuke and coal are cheaper. Hydropower can be throttled up and down easily however, once built, it is one of the cheapest forms of power, because there is no fuel. So, where it can be done, hydro is an overnight source of choice. GHG emissions will be almost invariant, the total amount released will be the same per hour, hour after hour.

Last fiddled with by Uncwilly on 2009-04-29 at 14:42 Reason: PC related.
Uncwilly is offline   Reply With Quote