In: Physics
A small city requires about 10 MW of power. Suppose that instead of using high-voltage lines to supply the power, the power is delivered at 120 V.
Assuming a two-wire line of 0.48?cm -diameter copper wire, estimate the cost of the energy lost to heat per hour per meter. Assume the cost of electricity is about 10 cents per kWh.
Given that
P =
10MW
=
10*106W
V = 120V
We know the formula of the power is P = VI
I
= P / V
Now power loss is
...........................(1)
Here P = 10*106W
V = 120V
?
=1.68*10-8?.m
? = 3.14
d
=0.48*10-2m
Putting the values in formula (1), we get
P/L = 12.9 MW/m
Cost of energy lost = 12900*.10 $/hr m = 129 $/hr m