One wing of the Homestead has 500 incandescent 60W light bul

One wing of the Homestead has 500 incandescent 60W light bulbs that are each on for a total of 6,000 hours a year; in bulk, the resort has paid $0.10 each and they last 1000 hours after which they need to be replaced. Since incandescents are being phased out, the Resort is converting to more energy efficient bulbs and wants to compare the cost-effectiveness of the incandescents to compact fluorescent lamps (CFL) and LED lamps.

a) Calculate the energy savings over one year (in kWh) if the 60W incandescent bulbs were replaced by 13W compact fluorescent bulbs that last 10,000 hours and cost $2 each, and 8W LED bulbs that last 20,000 and cost $4 each.

Use the energy savings in kWh as the AES entry in the Economic Analysis spreadsheet for parts b, c, and d.

b) Assuming electricity rates at the Homestead of $0.08/kWh, rate escalation at 2% per year, and interest rate of 4% per year, use the spreadsheet to calculate the simple payback period (SPP), in years and in days (assuming a 365-day year), for the CFL and LED options compared to incandescents. Ignore labor costs for now. Calculate bulb cost for one-year of use (i.e., 5 incandescents, ½ CFL, ¼ LED). (Hint: in comparing options 1 and 2, the total initial cost (IC) is equal to the incremental cost, or IC1-IC2).

c) Also calculate the CCE, PVS, NPV, and BCR for this investment, assuming n=1.

d) What are the SPP, CCE, PVS, NPV, and BCR if labor costs are included? Let’s say it takes 30 person-hours to change the 500 bulbs, at $12/hour. It will take 5 replacements per year for incandescents, ½ for CFLs, and ¼ for LEDs.

Table 5.5 Economic Analysis of Ener Systems and Efficien ments dsheet to calculate cost-effectiveness, with the low-flow shower head example a S Value Units Formula in Value Column AES 17.34 1o Btury (use appropriate energy unit) Enel Savi s or Production 30 otal Cost 10 $/100 Btu Ener Price Annual O ration & Mai intenance Cost Ener Price Escalation Rate nterest Rate Discount Rate n 20 years mber of years Capital Recove Factor Compound Growth Factor Present Worth Factor Uniform Present Worth Factor P S or units oda s Val E 180.61 or units E-PCGF Compound Growth of Present Value Present Value of discounted future value /(AES Pr) e Paybac k Period Cost of Conserved Ene Prese nt Value Savings Net Present Value Benefit-Cost Ratio BCR (AES Pr-o&m;)/ (IC CRF) calculated values

Solution

a)The total amount of incandacent bulbs need to cover a year =500*(6000/1000)=3000 pieces
cost to buy 3000 incandacent bulbs=3000*0.10=$300
Energy needed to glow incandacent bulbs over the year =500*60*6000=180000000 watt-hour
energy needed to glow compact flurocent bulbs over the year=500*13*6000=39000000 watt-hour
energy needed to glow LED bulbs over the year=500*8*6000=24000000watt-hour
Thus energy savings for using compact flurocent bulbs =180000000-39000000=141000000watt-hour=141000kWh
energy savings for using LED bulbs=180000000-24000000=156000000watt-hour=156000kWh