Power transformers can be used in power stations to raise the low voltage (e.g. 10kV) generated by generators to ultra-high voltage (e.g. 220kV or 500kV) to minimize transmission losses over long distances. In the distribution chain of life, transformers reduce the high voltage to the low voltage (e.g. 380V/220V) available to the user, ensuring the safe use of electricity in homes, factories and commercial facilities. Grid-connected wind and solar power systems, which are popular renewable energy sources worldwide, use transformers to convert unstable power into a stable voltage suitable for grid transmission.  With the development of smart grids, energy efficient transformer technology will continue to drive progress in the power industry.