As constraints on implementation of the forecast, it is considered that the installed geothermic capacity cannot be increased and that electrical capacity growth is achieved through combined cycle plants operating with natural gas. Moreover, the price of natural gas remains constant at 27 US$/Gcal (7 US$/thousand cubic feet, 7.2 US$/million BTU). Fig. 2 shows prices reported in the US for natural gas in dollars per million BTU (US$/MBTU). Prices of long-term contracts signed between CFE and California, US, were above these values.