As of August 2020 Chile had diverse sources of electric power: for the National Electric System, providing over 99% of the county's electric power, hydropower represented around 26.7% of its installed capacity, biomass 1.8%, wind power 8.8%, solar 12.1%, geothermal 0.2%, natural gas 18.9%, coal 20.3%, and petroleum-based capacity 11.3%. Prior to that time, faced with natural gas shortages, Chile began in 2007 to build its first liquefied natural gas terminal and re-gasification plant at Quintero near the capital city of Santiago to secure supply for its existing and upcoming gas-fired thermal plants. In addition, it had engaged in the construction of several new hydropower and coal-fired thermal plants. But by July 2020 91% of the new capacity under construction was of renewable power, 46.8% of the total solar and 25.6% wind, with most of the remainder hydro. Chile's electricity sector reform, which served as a model for other countries, was carried out in the first half of the 1980s. Vertical and horizontal unbundling of generation, transmission and distribution and large scale privatization led to soaring private investment. The 1982 Electricity Act was amended three times in 1999, 2004 and 2005 after major electricity shortages. Further amendments are envisaged. Electricity supply and demand Installed capacity There are four separate electricity systems in Chile: the Central Interconnected System (SIC, Sistema Interconectado Central), which serves the central part of the country (75.8% of the total installed capacity and 93% of the population, 15 GW capacity and 7.5 GW peak load); the Norte Grande Interconnected System (SING Sistema Interconectado del Norte Grande), which serves the desert mining regions in the North (23.3% of the total installed capacity, 4 GW capacity and 2.4 GW peak load); and the Aysén (0.3% of total capacity) and Magallanes (0.6% of total capacity) systems, which serve small areas of the extreme southern part of the country. The long distances between the four systems made their integration difficult, but after the 600 km SIC-SING 500 kV AC transmission project costing US$1bn came online in May 2019, Chile's northern grid (SING) and central-southern grid (SIC) are now connected into a single national wide area synchronous grid. Total installed nominal capacity in April 2010 was 15.94 GW. Of the installed capacity, 64.9% is thermal, 34% hydroelectric and nearly 1% wind power, with nuclear absent. The SING is mostly thermal and suffers from overcapacity, while the hydro-dominated SIC has been subject to