Integration of renewable sources of energy into power grid

The huge, ever growing demand for electrical energy has hitherto been primarily met through the combustion of fossil fuels, and conversion of heat liberated therefrom. The relentless exploitation of these resources has raised questions regarding emission of green house gases, particulate pollution, and their harmful effects on environment. It also brings into focus the sustainability of generation to satisfy the demand for energy in the coming decades, from fuels which are not inexhaustible. Renewable sources of power such as the sun, the wind and the tides offer solutions to these issues. The continuously falling cost of Solar and Wind generation technology has also made this option economically viable. They are rendered even more attractive by governments in many countries, which are keen to promote green and clean energy, by adoption of favorable policies. But the large scale use of renewable sources of energy give rise to many technical challenges for the power system engineers. It is necessary to overcome them before the renewable sources come into wide use in conjunction with conventional generation based on fossil fuels. An attempt is made in this paper to identify the issues which arise as a consequence of integration of the renewable sources with the existing power grids, and look for solutions to some of them, particularly the stability of voltage, through the control of reactive power and active power.