Addressing Grid Vulnerabilities with E-COMP

The U.S. electric grid is powering up for a new era of growth and strength—fueled by rising demand and the increasing use of inverter-connected resources that operate without traditional inertia. Integrating these types of new technologies will help strengthen the nation’s energy independence and drive economic growth. Yet, in the midst of surging energy needs, this integration will also increase the grid's complexity and vulnerability.

To meet the growing complexity of tomorrow's electric grid, PNNL developed its Energy System Co-Design with Multiple Objectives and Power Electronics (E-COMP) initiative. E-COMP leverages interdisciplinary expertise in power systems engineering, control theory, and optimization to build a foundational understanding for designing and operating the nation’s advancing energy system.

Energy expansion opportunities

The energy system, already growing in complexity, is experiencing added strain due to the interconnection of numerous components with highly variable outputs and behaviors. This includes the use of power electronics to control and direct electricity more efficiently. Although power electronics offer greater flexibility in adjusting how power flows, they introduce new types of behavior that traditional power systems weren’t designed to handle. This complexity is compounded by the rapid increase in electricity demand associated with data centers, manufacturing, and emerging technologies, such as electric vehicles. Resultingly, system strain and the need for more generation and load increase the risk of failure.

The complex mixture of old and new systems is challenging to model and understand, making it difficult to prevent system failures. Many traditional design and operational theories and methods are no longer effective or applicable. Moreover, there is a limited understanding of the markets and economics of these complex systems, which creates barriers to providing affordable energy to consumers. 

E-COMP focuses on understanding and modeling the behavior and stability of complex energy systems and leveraging the emerging controllability gained from power electronics. The initiative is helping to prevent vulnerabilities that could compromise grid reliability, security, and affordability.

Essential advancements for power grid optimization

“The E-COMP initiative is designed to fill critical knowledge gaps by developing advanced theories, models, and tools that will help guide the design and operation of the emerging complex energy system to ensure electricity is consistently available, secure, and cost-effective,” said Tim Salsbury, a PNNL controls scientist and E-COMP initiative lead. “By tying together advanced modeling, simulation, and optimization, E-COMP is uncovering design and operation innovations for modernizing the power grid and broader energy system.”

E-COMP integrates capabilities across three main technical areas:

• Understanding Behavior and Stability: Researchers develop modeling, control, and analysis methods to characterize, identify, and mitigate vulnerabilities.
• Co-Design Framework: This framework simultaneously optimizes the design and operation of energy systems, finding the optimal trade-off between multiple objectives such as reliability and cost.
• Multi-Entity Simulation Platform: A modeling and simulation tool that evaluates the impact of local decisions on the broader system, enabling more effective integration of new resources and loads into the existing system.

By leveraging interdisciplinary expertise in power systems engineering, control theory, and optimization, PNNL is uncovering the root causes of grid instabilities and devising strategies to prevent them. These efforts enhance grid reliability, security, and affordability while enabling smarter operational strategies and ensuring the grid can support the integration of distributed energy resources.

Addressing grid instability

As demand for electricity grows, power electronics-based systems are increasingly supplementing or replacing traditional electromechanical devices and systems on both the load and generation side. According to projections published in IEEE Electrification Magazine, up to 80 percent of all electricity will flow through power electronics devices within 10 to 15 years. 

While these technologies bring significant benefits, grid instabilities caused by power electronics-driven devices are already evident. For example, in July 2024, according to a North American Electric Reliability Corporation (NERC) incident review, an unexpected 1,500 MW drop in data-center-type load was observed in the North American Eastern Interconnection. In August 2021, unexplained power oscillations in Great Britain’s grid led to costly and widespread outages, as described in a report by the Government of the United Kingdom. Similar incidents—such as the sudden loss of 1,200 MW of power in California in 2016, as described in this NERC interruption disturbance report, and a blackout in South Australia that same year, according to this Australian Government report—underscore the urgency of addressing these vulnerabilities. These events highlight gaps in understanding systems with fast power electronics and the need for new design and operational approaches to ensure grid stability while accommodating diverse energy resources.

Turning research into real-world solutions

E-COMP researchers are already making strides in several areas, including reducing grid instability associated with power electronics, specifically power inverters that change electricity from one form to another. These scientists are also utilizing advanced control methods and AI to integrate inverters into the grid stabilization solution, thereby mitigating wide-area oscillations in voltage, current, or power.

Criteria for grid-forming inverters

In a letter published in IEEE Transactions on Power Systems, PNNL E-COMP researchers consider options to understand and limit the ways in which power inverters cause grid instability when recovering from a disruption or interruption in current flow, or from a fault. Researchers explore various methods to limit the amount of current during faults, including a new approach to determining when an inverter, using multi-loop control, can stop limiting its current after a fault is fixed. Researchers successfully tested the theory using simulations while exploring methods for limiting current, like prioritizing certain types of current, using circular limits, and virtual resistance.

Said PNNL electrical engineer and lead author, Xue Lyu, “Getting these types of inverters back in sync with the power grid after a fault may represent a profound shift in how energy is restored and delivered, which could lead to fewer blackouts or power quality issues for consumers.”

AI for grid coherency awareness

Specific to making inverters part of the solution for power grid stabilization, as published in IEEE Control System Letters, PNNL E-COMP researchers detail how they are using a machine learning approach called reinforcement learning for sequential decision-making to support inverter controls that stabilize wide-area power fluctuations. The new approach could help stabilize oscillations by learning how inverters and generators naturally group and oscillate.

PNNL electrical engineer and contributing author Kyung-bin Kwon said, “Ultimately, taking into account how parts of the grid naturally move or behave together, or coherency awareness, could be a smarter way to control large power grids, especially ones that rely heavily on modern energy sources that connect to the grid through inverters.”

A more resilient future

Concluded Salsbury, “E-COMP will play a crucial role in the planning and operation of the nation’s future energy system by integrating a diverse mix of energy resources and loads with optimal trade-offs between reliability, security, and cost-effectiveness.”

The insights and tools developed through E-COMP will have far-reaching impacts, from preventing costly outages to improving the overall reliability of the power grid and broader energy system. As the energy system evolves, PNNL remains committed to pioneering solutions that strengthen the nation’s energy infrastructure.