I have accurate statistics about the total length of high-voltage (110-400 kV), medium-voltage (1-70 kV) and low-voltage (0-1 kV) transmission lines in my country, and they are:
- High-voltage: 22 500 km
- Medium-voltage: 140 000 km
- Low-voltage: 240 000 km
I would like to obtain an accurate estimate of how much aluminum is used for the transmission lines, but so far have failed to find any. I assume all lines have approximately 3 conductors due to the 3-phase system (in some cases there may be a fourth one, but 3 is a good approximation). Thus, to calculate the amount of aluminum, I would need an accurate estimate of conductor radius for high, medium and low voltage networks. Obviously, I cannot climb to reach the transmission line and measure its size by a vernier caliper!
One source I found is http://large.stanford.edu/courses/2010/ph240/harting1/ where a figure says that optimal radius (one that minimizes total costs) for a 2.25 GW 3-phase 765 kV line is 4 centimeters.
Thus, for a total length of 402 500 km of transmission lines, there would be 402500000*pi*0.04^2 = 2023186 square meters of aluminum, or by weight 2023186 m3 * 2700 kg/m3 = 5462602200 kg of aluminum, per phase. Three phases would require 16.4 million metric tons of aluminum. Per capita, that would be approximately 3 metric tons, or 3000 kg.
I feel that estimate may be a bit on the high side, because I found a statistic that about 25 kg of aluminum is used per year per capita. Thus, it would require 120 years of production to manufacture 3 metric tons of aluminum per capita. I don't believe that all lines, including the low-voltage (and presumably low-current) lines would use 4 cm radius conductors.
So, how much aluminum does a kilometer of high voltage (HV), medium voltage (MV) or low voltage (LV) transmission line use?