Transelec’s network is highly reliable as shown by the SIC availability system indicator, which is defined as the percentage of the total number of hours that power is available for transmission at tap off points. Since its creation, this indicator has remained consistently above the 99.99% mark, a figure that meets the highest international standards and is far in excess of those required by Chilean regulations (99.44%). Taking as a parameter the periods of highest demand, the standard establishes that the system unavailability cannot excede 311.4 minutes (5.19 hours) per year, while the actual fact is, by way of example, that the system was unavailable for 26 minutes during 2007.
Another relevant indicator of the transmission reliability service provided by Transelec is the ETI, which stands for “Equivalent Time of Interruption” and measures the total energy not supplied to Transelec’s non regulated clients over a twelve-month period, expressed in minutes per year of system failure. During 2007, the SIC’s ETI reached a value of 13.7 minutes, of which 6.4 where caused by installation and operational dificulties in the company while the remaining 7.3 minutes were caused by force majeur events and third party responsablities.