Abstract
Responsive load is the most underutilized reliability resource available to the power system. Loads are frequently barred from providing the highest value and most critical reliability services; regulation and spinning reserve. Advances in communications and control technology now make it possible for some loads to provide both of these services. The limited storage incorporated in some loads better matches their response capabilities to the fast reliability-service markets than to the hourly energy markets. Responsive loads are frequently significantly faster and more accurate than generators, increasing power system reliability. Incorporating fast load response into microgrids further extends the reliability response capabilities that can be offered to the interconnected power system. The paper discusses the desired reliability responses, why this matches some loads' capabilities, what the advantages are for the power system, implications for communications and monitoring requirements, and how this resource can be exploited.