Wind energy already makes a significant contribution to climate protection and independence from fossil and nuclear fuels in Germany today. By 2030, more than 50 GW of onshore and offshore wind power plants are to be installed, while only 20 GW of coal power plants and no nuclear power plants will remain. The book analyzes the system-technical and economic aspects of this complete restructuring of the electrical energy system, taking into account German and European energy law. Key topics include: optimization of wind turbines and their grid connections, expansion of power grids using new environmentally friendly technologies, balancing the large fluctuations in wind energy supply with other renewable or low-CO2 energy sources, and the market-driven displacement of coal-fired large power plants. With newly developed optimization methods, the book provides foundational knowledge for research and development.