Microgrids for Everyone?
Source: David Shadle | · T&D WORLD · | August 17, 2022
Today, there appears to be more proponents with a variety of arguments for installing microgrids, including environmental benefits, improved reliability, resiliency, and economics. Is a microgrid the best approach for most customers?
Source: T&D World
Interest in microgrids has grown in parallel with our fixation about distributed energy resources. Their purpose is to distribute electricity within a localized network, drawing upon onsite generation as needed, with the capability of islanding and operating autonomously from the grid during outages. Frequently, the justification for operating a microgrid has been economics as in the case of combined heat and power (CHP) on a college campus or in an industrial plant. Today, there appears to be more proponents with a variety of arguments for installing microgrids, including environmental benefits, improved reliability, resiliency, and economics. Is a microgrid the best approach for most customers?
One might think so based on the number of articles and vendor coverage microgrids receive. Indeed, T&D World is guilty as charged with significant coverage of the subject over the last several years. One of the best articles entitled “Lessons Learned from Microgrid Projects” was submitted by Duke Energy. The article describes two microgrid pilot projects developed, commissioned, and tested by Duke at its facilities. Lessons learned from the utility’s experience make it clear that developing and operating a safe, reliable, useful microgrid is not as simple as some industry literature suggests.
The Duke pilots established that successful microgrids require: a detailed understating of load diversity and a proper generation asset mix; through modeling/engineering with short circuit and direct-current arc-flash analysis including for system secondary voltages; system protection that reflects solar and battery grounding systems (as applicable) in grid connected and islanded mode; designs reflecting battery cooling and aux power requirements; integration and testing of disparate distributed resources, often supplied by different vendors at different times; meeting conditions at the point of interconnection as well as permit or system capability limitations during islanded operation; and ensuring all control and communication devices have properly sized uninterruptible power supplies to ensure safety and system protection during mode transitions.