What is Long-Term System Planning?
Long-term system planning refers to the planning activities conducted regularly by utilities and power system operators to inform investment decisions on generation, transmission, and distribution capacities. This ensures the generation capacity meets the system demand reliably and economically during normal and abnormal operating conditions for the planning horizon, typically 5-20 years.
The rapid addition of solar energy and other new energy technologies onto the grid has changed the ways in which grid planning is performed. These rapid changes of the electric power system require the development of new tools and models—particularly for analyzing the variable and dynamic behaviors of the electric power system—so the grid can be run reliably and contribute to our energy resilience and security. Learn more about the basics of systems integration.
Why is Long-Term System Planning Important?
As more solar is added to the grid, it presents challenges for system operators because of its variable nature: solar can only generate electricity when the sun is shining, so it must be balanced with other sources of generation and storage to meet customer demand. Conducting simulations of different grid scenarios to assist with long-term planning can help determine optimal resource allocations far in advance to prevent any problems such as resource inadequacy or wasteful curtailment.
Modeling and simulation have become quite advanced for different sections of the overall grid. These models have included the bulk power system, sub-transmission networks, distribution feeders, and variable energy resources, including inverter-based resources. But the rapidly changing features of each of these interconnected subsystems affects the whole, so it is important to better understand the dynamic behavior of a fully integrated grid with large share of inverter-based resources.
The U.S. Department of Energy Solar Energy Technologies Office (SETO) funds research to improve system planning models and tools in order to meet its goal of improving the ability of solar energy to integrate into the country’s electric grid, and to combine solar technologies with storage, efficiency, and other value-adding technologies that allow solar to contribute to enhanced grid reliability and resilience. Learn more about SETO’s goals.
SETO Research on Long-Term System Planning
Projects in this topic area investigate the optimal placement of system components, such as solar photovoltaics and energy storage, develop modeling and simulation methodologies for long-term system planning under various constraints, and develop software tools to help grid planners manage the grid. Specifically, projects focus on addressing generation variability management, improving voltage and frequency stability, improving system flexibility, and developing new interconnection standards. Several of SETO’s funding programs have projects that focus on long-term system planning for solar integration:
- Operation and Planning Tools for Inverter-Based Resource Management and Availability for Future Power Systems (OPTIMA) funding program - developing tools and methodologies for grid planners to incorporate the dynamic features of variable renewable energy resources, inverter-based resources, and distributed energy resources.
- Solar Energy Technologies Office Lab Call FY2022-24 funding program – providing improvement of transient and dynamic models for solar grid integration, simulation of large-scale power systems, and integration of the required models into planning tools for studying the system’s dynamic behavior during the planning phase to ensure system stability.
- Advanced Systems Integration for Solar Technologies (ASSIST) funding program – investigating dynamic modeling of solar generation and systems with an aim to perform faster-then-real-time simulation.
- Solar Forecasting 2 funding program – improving the management of solar power’s variability and uncertainty, enabling its more reliable and cost-effective integration onto the grid.
- Solar Energy Technologies Office Fiscal Year 2019 funding program – supporting dynamic modeling and simulation, especially transient analysis of smart inverters, for better abilities to respond to extreme events, like fires and cyberattacks, and rapidly restore service if interrupted.
- Solar Energy Technologies Office Lab Call FY19-21 funding program – providing foundational analysis and evaluation of solar integration challenges, as well as strategies for advancing power system planning and operation, power electronics, sensors and communication technologies, and cybersecurity.
To view specific projects that support system planning and operation, search the Solar Energy Research Database.
Additional Resources
- System Integration Basics
- National Renewable Energy Laboratory: North American Renewable Integration Study (NARIS)
- National Renewable Energy Laboratory: Best Practices for Validating Hosting Capacity Analyses
Learn more about systems integration research, other solar energy research in SETO, and current and former funding programs.