Many renewable energy sources produce electricity, and the fundamental operation of a national alternating current electric power system is described. The difference between real and reactive power is explained. The impact of renewable energy sources on the voltage of the power system is demonstrated through an example and approaches to controlling network voltages are discussed. The control of frequency is described and the importance of maintaining sufficient inertia is highlighted. Scheduling generation in a power system with significant fraction of renewable energy generation is explained. Approaches to demand-side participation and the importance of this concept are discussed. The connection of onshore and offshore wind farms to the power system is discussed. Approaches to the design of PV farms are illustrated. The chapter is supported by 6 examples, 10 questions with answers and full solutions in the accompanying online material. Further reading and online resources are identified.

Rapid economic growth in China has predominantly relied on coal-fired electricity and coal use in industry, generating an increasing range of economic, environmental, and health costs. While many policies aim to restrict – and reverse – coal’s growth, the transition from coal to low-carbon alternatives is neither automatic nor just around the corner. Entrenched technological systems, political interests, and historical factors serve to maintain coal’s dominance. For China to prepare for deep decarbonization by mid-century, it must proactively convert coal from a barrier to a bridge – productively repurposing and valuing coal assets for flexible operation, addressing the difficult coal-based district heating infrastructure in the north – develop alternative fuels and feedstocks for industry and households, and mitigate the immense socioeconomic consequences of this transition on governments, firms, and workers.