Cost of One Computer…Cost of One Computer…
During During School School Hours:Hours:
E=Pt E=Pt
=100W(8h) =100W(8h)
=800Wh=800Wh
=.800 kWh=.800 kWh
.8 kWh($.08/kWh)= .8 kWh($.08/kWh)= $.06$.06
Outside Outside School School Hours:Hours:
E=Pt E=Pt
=37W(16h) =37W(16h)
=592Wh=592Wh
=.592 kWh=.592 kWh
.592kWh($.08/.592kWh($.08/kWh)=$.05kWh)=$.05
Total: $.11 for one computer per day during the Total: $.11 for one computer per day during the School YearSchool Year
For One School Day
Cost of One Computer…Cost of One Computer…
During The During The
Summer/Summer/
Weekends:Weekends:
E=Pt E=Pt
=37W(24h) =37W(24h)
=888Wh=888Wh
=.888 kWh=.888 kWh
.888 kWh($.08/kWh)= .888 kWh($.08/kWh)= $.07$.07
Total: $.07 for one computer per day during the Total: $.07 for one computer per day during the summer/weekendssummer/weekends
For One Non-school Day
Cost of One Computer…Cost of One Computer…
During The School During The School Year:Year:
($.11/day)(180 school days/year)=($.11/day)(180 school days/year)=
$19.80 for one computer during the school year$19.80 for one computer during the school year
During The During The
Summer/Summer/
Weekends:Weekends:
($.07/day)(185 non-school days/year)=($.07/day)(185 non-school days/year)=
$12.95 for one computer during the summer $12.95 for one computer during the summer and on weekendsand on weekends
Total for the entire year for one computer: Total for the entire year for one computer:
$19.80 + $12.95 = $19.80 + $12.95 = $32.75$32.75 for one computer per year for one computer per year
During the Entire Year
Total Cost of Computer System…Total Cost of Computer System…
($32.75 per computer/year)(220 computers)=($32.75 per computer/year)(220 computers)=
$7205.00 for all 220 computers over the course of one year$7205.00 for all 220 computers over the course of one year
($.06 during school hours/day)(180 days/year)(220 computers)= ($.06 during school hours/day)(180 days/year)(220 computers)= $2376.00 for all 220 computers during school hours over the course $2376.00 for all 220 computers during school hours over the course
of one yearof one year
Total amount saved: $4829.00Total amount saved: $4829.00
Asset or Liability?Asset or Liability?
Per Machine:::Per Machine:::
- MCPS: $300 per year- MCPS: $300 per year
- Must make at least $48.68 per month- Must make at least $48.68 per month
In total:::In total:::
- 12 machines = $3600.00 per year- 12 machines = $3600.00 per year
DATE 2002 20038/25 – 9/23 192,977 kWh 148,179 kWh
9/24 – 10/22 135,829 kWh 124,712 kWh
10/23 – 11/23 135,804 kWh 134,340 kWh
11/24 - 12/23 167,628 kWh 153,431 kWh
TOTAL 632,238 kWh 560,662 kWh
Comparison of Savings Before and After Green Schools Initiative