This issue is an unusual effort to explore a single important subject from a number of perspectives. Here we have asked commentators in five transmission systems in different parts of the country to describe, among other things, how incentives and regulatory requirements and other factors affecting market designs have provided for adequate and appropriate new generation or left it deficient. Related problems have involved renewables and their impact on requirements for associated power plant construction and on the management of transmission. Problems range from wind power demands in the Pacific Northwest to the impact of an energy-only market design in ERCOT. As will be apparent from reading the various system-related comments, each system is focused on issues in different ways somewhat unique to it. Issues in several of the described systems have led to FERC filings for their resolutions with—in at least one case—important questions of statutory interpretation at stake.