The challenge of wind integration is to make best use of the variable and uncertain power source while maintaining the continuous balance between consumption and generation and high level of reliability in the power system. There is already experience of operating power systems with large amounts of wind power and integration studies give estimates on wind power impacts. Power systems are equipped to handle variability and uncertainty that comes from the electricity consumption, the load. Short-term wind forecasting is required to manage large amounts of wind power. The main impacts of wind integration are investments in grid infrastructure and efficiency losses in power plants when following the increased variations and uncertainty in the power system. Wind power will lower emissions while replacing energy produced by fossil fuels and can also replace some power plant capacity. However, wind's lower capacity value compared to conventional power plants is one integration impact of wind power, meaning higher total installed capacity in power systems with high wind penetration. Managing options for wind integration impacts includes proper wind power plant grid-connection rules, increasing transmission capacity and increasing flexibility that is available from generation plants and demand side. Further development of models and tools is required to study how entire power systems can be operated during the hours and days of very high penetration levels covering 60–80% of load.