In addition, in the course of the energy sector reform which began in 1998, some electricity facilities of the rural grids have been corroded, damaged, or generally could not meet the demand, and thus needed either replacement or modification, again incurring large expenses. The improvement of living standards and the economic development of rural areas, a consequence of electrification, stimulate electricity demand, and put power supply companies under permanent financial strain. Rural grids need constant renovation and maintenance. A survey conducted by the Institute of Electrical Engineering (JKD) in Inner Mongolia in late 2003 (Chinese Academy of Science, 2003) revealed that out of 5 240 PV/wind/battery hybrid systems for which statistics were available, a total of 2 119 systems (40.4%) were malfunctioning.