Correct Answer - Option 1 : 250 MW

Plant capacity factor: It is the ratio of actual energy produced to the maximum possible energy that could have been produced during a given period.

\(Plant\;capacity\;factor = \frac{{{\rm{Actual\;energy\;produced}}}}{{Maximum\;energy\;that\;could\;have\;been\;produced}}\)

\( = \frac{{Average\;demand \times T}}{{Plant\;capacity \times 100}}\)

\(= \frac{{Average\;demand}}{{Plant\;capacity}}\)

\(Annual\;plant\;capacity\;factor = \frac{{{\rm{Annual\;kWh\;output}}}}{{Plant\;capacity \times 8760}}\)

The plant capacity factor is an indication of the reverse capacity of the plant. A power station is so designed that it has some reserve capacity for meeting the increased load demand in the future. Therefore, the installed capacity of the plant is always somewhat greater than the maximum demand on the plant.

Reserve capacity = Plant capacity – Maximum demand

If the maximum demand on the plant is equal to plant capacity, then load factor and plant capacity factor will have the same value. In such a case, the plant will have no reserve capacity.

__Calculation:__

Energy generated/annum = Maximum demand × load factor × hours in a year

= 1000 × 0.75 × 8760 = 6.57 × 106 MWh

Plant capacity factor = (units generated/annum)/(Plant capacity × hours in a year)

Plant capacity \(= \frac{{6.57\; \times \;{{10}^6}}}{{0.6\; \times \;8760}} = 1250\;MW\)

Reserve capacity = plant capacity – maximum demand

= 1250 – 1000 = 250 MW