Question

Currently my nephew owns an old refrigerator (a 2003 Kenmore Coldspot) rated for an average draw of 653kW-hr/yr. According to his DP&L bill, electricity costs him $0.141/kW-hr.

a) How much will it cost to run his old refrigerator every year?  

653*0.141= $92.073

b) If a new refrigerator from Home Depot costs $500 and is rated at 500kW-hr/yr., how much will it cost him to run the new refrigerator?

500*0.141=$70.5

c) How much will he save each year by running the new refrigerator?

$92.073-$70.5=$21.573

d) Supposing the nice garbage man takes away his old refrigerator at no cost, how long will it take my nephew to recover the price of the new fridge from the money saved from the lower electric bills? Do you think it is worth it financially for my nephew to buy the new fridge?

$500/$21.573=23.18 number of years

e) DP&L gets the bulk of its electricity from the coal-fired W.H. Zimmerman power plant (Clermont County, Ohio)—the largest single unit power plant in the United States. It services 500,000 customers at a capacity of 1,300 Megawatts/day. As is well known, coal-fired power plants release greenhouse gases and heavy metals such as Hg (etc.) into the atmosphere. If all 500,000 customers in the DP&L region follow my nephew’s example and buy the same new refrigerator, what will be the total energy reduction each year?

f) What percent of Zimmerman Power Station’s yearly maximum capacity output does this energy reduction represent?

PLEASE JUST ANSWER E AND F. Thank you

Answer 1

-------------------- Solution of part e ------------------------------------------

Saving of energy by one customer for one year of time = 653 - 500 = 153 kW-hr/yr

or

Saving of energy by one customer for one year of time = 153 *3.6 M Joules/ Year =550.8 Mega Joules/ Year

Total number of customer = 500 000

So total saving in DP&L region for one year = 550.8* 500 000 = 275 400 000 Mega joules /yr

-------------------------------------- Solution of part f ----------------------------------

production of the power plant is 1300 *MWatt /day

Total Energy production for a year is = 1300 *3600*24*365 Mega joules /year

                                                     = 40 996 800 000 Mega joules /year

To find out percent we have to

= 0.672 %