Deck 17: Sustainable Operations

Question 1

(Bauxite to New Zealand) Australian bauxite ore is shipped 3,000 kilometers to New Zealand in a bulk cargo ship. The ship carries 300,000 metric tonnes of ore and consumers 1,400,000 liters of fuel oil on the journey. Fuel oil emits 38.2 kgs CO₂ per liter. For bauxite ore shipped from Australia to New Zealand, what is the emission of CO₂ (in kgs) per tonne kilometer traveled

Answer 1

Sustainability is one of the most important aspects of the modern businesses. Sustainability, on one hand, works on efficient uses of the resources and on the other side, emphasizes on reduction of total emission per unit of output produced.
The fuel oil emits 38.2 kg of CO₂ per litre of fuel and the fuel used for transportation is 1,400,000 litres.
So,
Compute the emission as follows:
So, the emission of CO₂ is

Question 2

A consumer who lives in New York switches from a 60 watt incandescent light bulb to an 8 watt LED. Assume usage remains the same, which is 4 hours per day on average. Electricity costs the consumer $0.12 per kWh. (A kWh is the amount of electricity need to produce 1000 watts of energy for 1 hour.) The incandescent light bulb costs $0.40. The LED costs $12.00. The LED lasts 27,000 hours whereas the incandescent light bulb lasts 1000 hours.
a. Including the cost of replacement bulbs and the cost of electricity, how long does it take for the LED to breakeven (That is, after how much time will the consumer have spent as much with the LED as with the incandescent light bulb.)
b. The consumer's electricity emits 450 kgs CO₂ /MWh. (1 MWh = 1000 kWh.) How many kgs of CO₂ would the consumer emit to operate the 60 watt light bulb for one year

Answer 2

The breakeven point between two alternatives happens at a time point when the total cost (i.e. the sum of all fixed and variable cost) becomes the same for both the alternatives.
a.
Let us define
as the time in hours when the breakeven occurs for the LED.
Compute the total cost of using one LED for t hours as follows:
Purchase cost of one LED = $12
So,
--- (1)
Compute the total cost of using one light bulb for t hours as follows:
Purchase cost of one bulb = $0.4
So,
---- (2)
For breakeven to happen, equate equation (1) and (2) as follows:
However, note that this value is more than 1,000 hours which is the life of one bulb. So, it is not possible to take this value as the breakeven hours. Re-compute the breakeven by considering two bulbs purchased i.e. double the purchase cost from $0.40 to $0.80.
Rounding off, the total hours after which the LED will become breakeven with the bulb is
b.
First, compute the total hours of operation in one year.
So, in a year
of CO₂ will be consumed by LED.