The Eastern Interconnect Grid

More on Resource Depletion Timescales

The timescale again is given by the following which we derived earlier:

T_e = 1/k * ln (Rk/r_o +1)

where k = growth rate
R = total resource available
r_o = initial consumption rate

Some examples to do in Excel. Calculate resource depletion time scales for various values of k.

• Coal (US): R = 200 (billion tons) r_o = 1 (2001)

• Natural Gas (US): R = 200 (tcf) r_o = 22
  Natural Gas (World): R=161 (tcm) r_o = 2.5 (2002)

• Oil (World): R = 1000 r_o = 28 (2001)

• Lead (World): R = 130 (million tons) r_o = 3

• Nickel (World): R = 58 (million tons) r_o = 1.25

• Aluminum (US): R = 20 (million tons) r_o = 5.3 or 3.7 (where the latter includes recycling)

• Cooper (US): R = 45 (million tons) r_o = 2 (1996)
  World: R = 320 r_o = 9

• Silver (US): R=31 r_o =1.6 (1996)
  World: R = 300 r_o = 15

  Now in the real world, consumption curves are modified by economics and so may look something like this.

  And this makes trend extrapolation difficult.

  Another example of this difficulty is provided by the following data:

  1920  39000  
  1930  54000 
  1940  69000  
  1950 125000   
  1960 163000 
  1970 213000 
  1980 275000 
  1990 283000
  2000 323000 
  
  2030: ???