System Technology Development for Grid Integration
One primary focus of the Systems Integration subprogram's research and development (R&D) efforts is to improve ways for distributed solar technologies to communicate with the electric grid. In the near term, the emphasis is on distributed solar technologies, specifically photovoltaics. But it will soon encompass nondistributed solar technologies, such as concentrating solar power.
Distributed and Central Generation
For renewable energy, distributed energy generation describes the production of energy close to where it will be used, and power capacity usually ranges from 1 kilowatt to 5 megawatts (MW). In contrast, central generation ranges from 10 to 1,000 MW and supplies power to locations much farther away through transmission lines. Electric utilities often tap into solar electricity for distributed applications, such as near substations or at the end of overloaded distribution lines, to avoid or defer costly upgrades of transmission lines.
In regard to distributed solar system technologies, the Systems Integration R&D activities emphasize improving controllers, inverters, and other interconnection mechanisms that integrate with building energy management, loads, energy storage, and advanced communication controls. In addition, this R&D concentrates on advanced inverter and balance-of-systems functionality to improve grid integration.
Communication Tools
To manage large amounts of solar electricity, reliable and advanced solar systems are needed that can communicate with the electrical distribution system and interact intelligently with electricity loads and energy storage.
The Systems Integration subprogram plans to meet this need through two specific tasks:
- Solar Energy Grid Integration Systems (SEGIS)—develops advanced technologies by directly funding industry projects related to inverters, controllers, and advanced communication controls.
- Advanced Systems and Components for Systems Integration—focuses on fundamental R&D conducted at two of the U.S. Department of Energy national laboratories, Sandia National Laboratories and the National Renewable Energy Laboratory in collaboration with universities and industry to identify and develop advanced capabilities for inverter, controller, balance-of-system, and energy management system technologies. These activities complement the SEGIS efforts.
Energy Storage
In addition, the Systems Integration team will address advanced energy storage. These activities will assess how energy storage systems can be integrated with distributed renewable energy to improve reliability, load shifting, and system optimization functions, increasing the economic competitiveness of distributed solar energy.
For our energy security and environmental health, these systems integration efforts are geared to changing the country's unidirectional grid, which can only handle one-way power flows, to a more bidirectional and smarter electrical grid of the future.