Temporary shortfalls of electricity supply can occur as a result of a drought, a heat wave, a breakdown in a power plant or partial loss of transmission capacity. The traditional response has been to cut power to customers while trying to restore supplies but lackouts may be economically and politically unacceptable if the shortage is expected to continue more than a few hours. An alternative approach is to launch an aggressive program to quickly conserve electricity relying on a combination of measures to improve energy efficiency and change consumer behavior. Several regions, including Brazil, California, New Zealand, and Norway have recently implemented such programs. It is possible to quickly reduce electricity demand 3 – 20%, sometimes with programs started in only a few months. Moreover, the reductions in demand can be accomplished without major economic disruption or hardships.These results (and the policies that achieved the savings) are important because temporary shortfalls in electricity supply are likely to occur more often. De-regulation and market liberalization have led to reduced reserves and safety margins through the whole electricity supply chain. Global climate change, appearing in the form of increased weather variation, is likely to provide disruptions too. In Iran we have very cheap tariff also. In this paper we discuss about International Energy Agency patterns, experiments & recommendations and some succesful cases in Yazd. 1) Yazd