Accommodating High Levels of DER

Deck: 

Understanding What Reliability Entails

Understanding What Reliability Entails

Fortnightly Magazine - May 2017
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Whether or not you work in the electric industry, you have probably already experienced and observed the unprecedented change transforming the bulk power system, or BPS, across North America.

The electricity grid as we know it is in the midst of an evolutionary shift that will shape our energy resources for years to come. The rules of the road are evolving to accommodate the expected resource mix change. Swift action by state, federal and provincial regulators is needed so the electric industry can build and reliably operate the grid of the future. There has never been a more critical time for understanding the key elements of electric reliability.

Across North America, state and provincial public policy initiatives are strongly influencing the types of resources being added to the bulk power system. They are also encouraging low cost and low environmental impact offsets on the distribution system, such as energy efficiency, demand-side management and distributed energy resources (DER).

EES North America

The rapid deployment of distributed solar photovoltaic systems, energy management systems, microgrids, demand services, aggregated generation behind the retail meter and many other types of distributed generation is taking place.

Fundamentally, though, DER is a simple challenge. The BPS was not designed to support reverse flows, a predominance of inverter-based control, and the declining inertia that is used to ensure stability during grid disturbances.

While the pace of DER growth is largely dependent on state and provincial policies, the physics of the grid are universal. Changes to one part of the system can significantly impact another part of the system. DER requires more thoughtful consideration of the transmission-distribution interface.

NERC’s 2016 Long-Term Reliability Assessment, based on third-party research, highlighted the cumulative number of U.S. solar installations brought on line to date. There are more than one million installations, representing 27.5 gigawatts of direct current in operating capacity. That number is expected to increase to nearly 45 GW of direct current by 2020, with residential installations making up approximately fifty-six percent of that forecast.

California, North Carolina, Massachusetts, Arizona, and New York rank the highest in terms of existing and forecasted solar PV installations. Ontario, which is highly interconnected to the U.S. power grid, is also expected to significantly increase its penetration of distributed energy resources, or DER, in the coming years.

How DER affects the reliability of the bulk power system is an area that needs more study and analysis for the industry and policy makers. To help the industry begin to address DER uncertainty and technical challenges, NERC established the Distributed Energy Resources Task Force in 2016.

The task force completed a report issued by NERC in February 2017 that is the focal point of the Electric Reliability Organization’s DER work. The report

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