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: NYMEX gas $/mmbtu X Heat Rate = $/MWH. The question is, what heat rate would one use? Or how would Heat Rate be calculated and/or what benchmarks would be used for the heat rate? Reuters, ICAP, ICE, Platts? And how does one calculate the price for each zone in ERCOT?