Computers Causing 2nd Hump In Peak Power Demand

Hugh Pickens writes "Traditional peak power hours — the time during the day when power demand shoots up — run from 4 p.m. to 7 p.m. when air conditioning begins to ramp up and people start heading for malls and home but utilities are now seeing another peak power problem evolve with a second surge that runs from about 8 p.m. to 9 p.m. when people head toward their big screen TVs and home computers. 'It is [not] so much a peak as it is a plateau,' says Andrew Tang, senior director of the smart energy web at Pacific Gas & Electric. '8 p.m. is kind of a recent phenomenon.' Providing power during the peak hours is already a costly proposition because approximately 10 percent of the existing generating capacity only gets used about 50 hours a year: Most of the time, that expensive capital equipment sits idle waiting for a crisis. Efforts to reduce demand are already underway with TV manufacturers working to reduce the power consumption in LCD and plasma while Intel and PC manufacturers are cranking down computer power consumption. 'Without a doubt, there's demand' for green PCs, says Rick Chernick, CEO of HP partner Connecting Point, adding that the need to be green is especially noticeable among medical industry enterprise customers."

Comments

Re:Stupid Question

[mcgrew]

CRTs are power hogs, but your laser printer is the biggest power hog of your computer system. The fuser gets up to 2k F to melt the toner on the paper.

Plasma displays use less than CRT, LED uses less than plasma.

A space heater uses more juice than just about anything in your house save your AC or (if it's electric) your water heater. Your toaster comes in a good second (while it's actually toasting, which isn't long) followed by your microwave.

If a device's primary purpose is to heat something, it uses a shitload of electricity.

All your electric appliances/gizmos are rated in watts. Just RTFM, it's usually listed on the back page. If you have no FM it usually says on the back of the appliance how many watts it consumes.

Calculations of power use

[neapolitan]

Car battery capacity is usually between 40-60 amp-h. That is, if you wanted to use battery power for three hours of peak, you would get (generous estimation) of 20 amp-h per battery. Your battery gives 12 volts, and, again under ideal conditions you should get 12*20 = 240 W-h per battery for the peak time.

A standard light bulb is 100 watts. Your plasma TV may be 800-1200 watts.

Thus to run the TV for three hours you would need five batteries, and that assumes that you could run them to dry. Lead acid batteries can produce surge power pretty well, but it would likely be cost prohibitive unless you could get a lot of duty cycles out of them.

Looking at Sears -- a cheap car battery is around $50. Electricity costs $0.08 per kwh where I am. Thus to equal the cost of one battery you would need to produce 50/.08 = 625 KW-h of electricity before being spent. That is 625,000 W-h or 1,000 charge cycles.

I'm not sure if a battery can handle this before getting corroded and functioning badly. Of course, this is only the cost of the battery, and really what you care about is the delta cost from night and day electricity. Additionally, people could not use retail car batteries but could get cheaper lead-acid apparatuses.

At delta cost of $.05 per kw-h, then if you could get more than 1000 charge cycles from the battery, then anything above this is profit on the order of $.05 KWh * 1kW * 3h = $.15 = 15 cents per day for your plasma. Is it worth it?

The short answer is no. The long answer is probably not.