Gansu Province Home Solar System Development

Gansu, a western province featuring a land area of 455,000 km², faces an acute shortage of water resources, sparse vegetation, and serious water and soil loss. Given these circumstances, hydropower options are limited to the large-scale plants built on the vast Yangtze River (also known as the Yellow River). For small, remote communities gaining access to the electricity generated by these large-scale plants is problematic because of a lack of infrastructure and low income levels. Therefore, the World Bank's Renewable Energy Development Project has focused on the area in the development of household solar systems.
A home solar system can be defined as a small, self-sustaining photovoltaic system that consists of one or more solar modules, a battery and several 12-volt direct current (dc) appliances. During daylight, the battery is charged. The stored energy can be used for generating light and running appliances such as radios and televisions. When the battery is fully charged, the regulator disconnects the module in order to prevent the battery from becoming damaged. This is called 'high voltage disconnect' (HVD). Below a certain level of discharge, the battery can also be damaged. To prevent this, 'low voltage disconnect' (LVD) occurs before the battery is completely drained.