Question

Estimation question: "Smart" devices and appliances (think computers, washers/dryers, cellphones plugged in overnight to recharge) around the home go to "sleep" in order to save power. That said, many of these devices still draw up to 1W of power while you're not using them. Use devices that you have in your daily life.

A) estimate the total of this standby power consumption in the United States. How many 1-GWe power plants are at work just to supply this standby power?

B) Estimate how many tons of carbon are put into the air each year to supply standby power.

Show your work.

Answer 1

SO I have one phone, one computer, heater, AC and two or three other machines which go into sleep mode. On average sleep mode, six devices will consume 6 W of energy. US population is about 35 crore so on avg. sleep mode takes 6 *35 crore = 210 crore W = 2.1 GW. so almost two power plants of 2 GW power work to supply this standby power.

let's say that the 0.5 kg carbon burns to produce 1 kW-h.

So to generate 2 GW energy for 365*24 hours will burn 2*0.5*10^6 * 365*24 kg (8.8*10^9 kg almost 10810^6 tons) of carbon. This will also depend on the energy source the efficiency of the source.