The fuel input rate of a gas-fired generating unit is approximated as follows:
where PG is the 3∅ power output in MW. If the cost of gas is $5 per MBtu, find
(a) The fuel input rate when the unit is delivering 100 MW
(b) The corresponding fuel cost in dollars/hr
(c) The incremental cost in dollars/MWh
(d) The approximate cost in dollars/hr to deliver 101 MW