Distributed Energy Resources

Report Details Challenges, Recommendations As Renewables Proliferate

A white paper by the Eastern Interconnection Planning Collaborative (EIPC) calls for operators and planners to be more engaged in the discussions about how the electric grid will evolve to meet the challenges of rising levels of renewable energy penetration.

The paper, Planning the Grid for a Renewable Future, says to ensure continued delivery of reliable, efficient, and affordable electric power, policymakers should be aware of the opportunities and challenges of integrating greater amounts of renewables onto the grid.

The white paper draws on lessons learned through historical experience and on studies of future conditions as they relate to the planning and operations of systems with a high penetration of renewables.

EPIC is composed of 19 planning coordinators from the Eastern and Central United States, including the PJM Interconnection, the Midcontinent Independent System Operators, the New York Independent System Operator, ISO New England, Southern Company, Tennessee Valley Authority, and MEAG Power.

The white paper identified several key challenges presented to grid operators by rising renewables penetration. For instance, traditional transmission planning focuses on systems built to move power from central generating stations to distant load centers. That pattern is changing, the paper noted, as renewable resources are being sited to make the best use of wind or solar availability, but those resources are not necessarily near existing transmission lines.

In addition, studies have shown that the proliferation of intermittent resources has resulted in a decline in grid performance, EPIC said. Changes are also occurring in load composition as a result of the proliferation of home backup generators, home electric vehicle chargers, and the increased penetration of rooftop solar arrays, and whole-building battery backup systems.

Grid planners also face challenges as the number of potential renewable projects seeking to connect to the power system has increased exponentially over the last 10 years. “Currently, the lack of standardized performance requirements for renewable resources with inverter-based control systems has been the cause of significant delays in the interconnection study queues of system planners across the Eastern Interconnection due to the large variety and rapid change in designs,” the EPIC report noted.

Operating the power grid has also become more challenging, EPIC said, because of limited transmission availability, the need to maintain the proper mix of generation resources to accommodate intermittent renewable resources, and load and resource uncertainty because of varying weather conditions.

Monitoring and correcting grid stability in real time is becoming more complex and is going to require the development of market products, such as ancillary services for voltage support, reactive power, and frequency response, EPIC said.

The report also noted the personnel challenges grid operators face. Most transmission planners today are familiar with control systems based on legacy synchronous generation. Going forward, transmission planners will need to develop a better understand of the quickly evolving technology of inverter-based resources, and it will take time and resources to train workers who can adapt to and take over those control and planning functions, EPIC said.

In terms of recommendations, EPIC stressed the need for coordination as it has become more problematic for policies in one jurisdiction or region to be walled off from policies in another.

EPIC recommended the enhancement of policy coordination across the “three-legged stool” of planning, cost allocation and siting. One key area where coordination will be critical is in transmission where policymakers will have to deal with the challenges of who is going to pay for new transmission assets needed to accommodate higher levels of renewable resources and the issues of siting those new lines.

EPIC also said regulators, industry and stakeholders should develop the capability “to monitor and correct course in a timely fashion if a particular path is leading to unnecessarily higher costs, limited choice for customers or negative reliability impacts.” Regulators could consider a “Reliability Safety Valve” mechanism in any future legislation, EPIC said.

And, finally, “as the pace of change continues to accelerate, it is more important than ever to work more proactively together,” EPIC said, recommending that policymakers “considering renewable portfolio standards, carbon dioxide standards, or other similar energy-related goals take the affirmative step of inviting system planners and operators to provide input.”

The challenges facing the industry and the grid are not “insurmountable, nor do they argue against moving forward with policies supporting renewables,” however, “when policymakers craft timelines, goals and deadlines, it is essential for policymakers to consider and balance the need to ensure that the power grid can remain reliable,” EPIC said.