Question

A wind generator has an output power of 2.5 MW.

How long does it take to generate 250 GJ of electrical energy?

power = \frac{\text{energy transferred}}{\text{time taken}}

time taken = \frac{\text{energy transferred}}{\text{power}}

power = 2.5 MW = 2.5 x 1,000,000 W = 2,500,000 W

(1 MW = 1,000,000 W)

energy transferred = 250 GJ = 250 x 1,000,000,000 J = 250,000,000,000 J

(1 GJ = 1 000 000 000 J)

time taken = {250,000,000,000 J}\div{2,500,000 W}

time taken = 100,000 s

100,000 s = {100,000}\div{60} = 1666.7 minutes

1667 minutes = {1667}\div{60} = 27.8 hours.

It takes the wind generator 27.8 hours.