If I wish to determine wholesale cost of power, $/MWH in ERCOT, per zone, I know that (in general) the equation would be Gas price X Heat Rate = Power price Example: Jan 2010 Power, $/mmbtu; NYMEX Jan. gas $/mmbtu X Heat Rate = $/MWH. ( for Jan. 2010) The question is, what heat rate would one use? mainly, how would Heat Rate be calculated and what benchmarks would be used? Reuters, ICAP, ICE, Platts? And how does one calculate the price for each zone in ERCOT?