Calculation
| Plastic on jobs that allow regrind, in pounds per year | 5,000,000 lb x 50 percent = 2,500,000 |
| Of that, plastic ground up and molded again, in pounds per year | 2,500,000 lb x 1.5 percent = 37,500 |
| New plastic the plant no longer buys | 37,500 lb x $1.50 per lb = $56,300 |
| Less what the grinders cost to run | 6 grinders x (6,000 kWh at 10 cents + $150 of blades + 25 minutes a week of a handler at $30 an hour) = $8,300 |
| What fixing it could save per year | $56,300 - $8,300 = $48,000 |
Assumptions
| Value | ||
|---|---|---|
| Share of the plastic on jobs that allow regrind | 50 percent | |
| Of the plastic on jobs that allow regrind, the share molded again | 1.5 percent | |
| Grinders, one at each job whose bin is heavy enough | 6 grinders | |
| Price of one grinder on a cart | $7,500 | |
| Power one grinder draws while its press runs | 1 kW | |
| A material handler's time per grinder each week | 25 minutes | |
| What a recycler pays for a pound of sorted scrap | 0.15 dollars a pound | |
| A handler's time each week to sort the bins for a recycler | 60 minutes | |
| Resin molded per year | 5,000,000 lb | |
| Price of resin | 1.5 $/lb | |
| Cost of one operator hour | $30 per hour | |
| Price of electricity | 10 cents per kWh |
Share of the plastic on jobs that allow regrind
50 percent
Of the plastic on jobs that allow regrind, the share molded again
1.5 percent
Grinders, one at each job whose bin is heavy enough
6 grinders
Price of one grinder on a cart
$7,500
Power one grinder draws while its press runs
1 kW
A material handler's time per grinder each week
25 minutes
What a recycler pays for a pound of sorted scrap
0.15 dollars a pound
A handler's time each week to sort the bins for a recycler
60 minutes
Resin molded per year
5,000,000 lb
Price of resin
1.5 $/lb
Cost of one operator hour
$30 per hour
Price of electricity
10 cents per kWh