Challenges of Integrating Large Amounts of Wind Power

Wind energy has experienced remarkable growth over the last decade, due in part to renewed public support and maturing turbine technologies. But often hidden from public view are the difficulties and challenges associated with introducing a new technology into an older electrical system of established infrastructure. Many early wind turbines utilized a squirrel-cage or wound-rotor induction generator to produce electricity. These generators allowed small variations in rotor speed thus improving energy capture and reducing torque shocks caused by wind gusts. However, they absorbed large amounts of reactive power and sometimes caused severe voltage stability problems on the grid. This paper explores some of the solutions that have resulted over the years, including the introduction of two new variable-speed generator types, doubly-fed induction and synchronous machines. It also considers the evolution of new grid codes and turbine improvements that make wind energy more grid-compatible to ensure further growth of this promising renewable source of energy.