Microgrids Are Key To The Future Energy System

Real-world experiences of microgrids demonstrate their key role in the modernization of the electricity grid.
Published: Tue 09 Jun 2015

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With advanced microgrids at the cutting edge of development, real-world experiences will demonstrate their potential and lead to further advancements.

Borrego Springs microgrid demonstrates islanding

San Diego Gas & Electric (SDG&E) has revealed that in the spring its Borrego Springs microgrid was used to power the entire community during a planned grid maintenance with renewable power from the nearby 26MW Borrego Solar facility, in addition to the onsite generation and energy storage systems. [Engerati-Borrego Springs Microgrid Grows In Scope]

The occasion was for work on the transmission line that usually feeds the community that had been damaged by lightning, requiring replacement and repair of three transmission poles. This would usually require a 10-hour sustained outage to the entire community of Borrego Springs.

“SDG&E demonstrated in a real-world situation how we can use innovative technology to create a more resilient and sustainable grid for our customers,” said Dave Grier, SDG&E's vice president of electric transmission and system engineering. “Borrego Springs was entirely separated from the main grid, running on the microgrid's local onsite resources for nine hours as we conducted necessary maintenance. This ability to operate independently of the grid when necessary is exactly what the microgrid was designed for and the fact that we were able to accomplish this using local renewable energy is an added benefit.”

The majority of power during the operation was generated from the Borrego Solar facility, using batteries and traditional distributed generation to "follow the load" and fill in gaps created by the solar facility due to intermittencies. While the switch to the microgrid was seamless, the switch back to the repaired transmission feed required an outage of less than 10 minutes.

Nice Grid demonstrates transactive energy management

Alstom has played a major role in the development of microgrid technologies. In the Nice Grid project in France, which is focussed on optimizing the integration of high levels of solar PV into the LV grid, the company has developed an architecture to manage distributed energy resources based on a transactive approach, building on experiences from earlier projects with Duke Energy and the Pacific Northwest demonstration. [Engerati-Build your Microgrid learning from the NiceGrid experience]

Experience over 55 days, including 37 days in summer and 18 days in winter, when different grid constraints occur, have demonstrated the efficacy of the system. Further tests are aimed to refine the cost-benefit analysis.

“We see Nice Grid as the natural evolution of the further integration of applications into the control room environment,” said Laurent Schmitt, vice president Smart Grid Solution, Alstom Grid, in describing the project in the Engerati webinar.

Other elements of the project, which forms part of the Grid4EU initiative, include testing microgrid islanding and developing the prosumer role of the consumer. [Engerati- Three Innovative Smart Grid Projects]

Microgrid centre of excellence in Philadelphia

Last year with support from the US Department of Energy, Alstom became involved in an initiative to develop a community microgrid demonstration at Philadelphia’s former naval shipyard, now a modern business campus with offices of more than 145 companies in the office, industrial and R&D sectors. [Engerati-Philadelphia Microgrid To Improve Grid Resiliency] Taking the partnership a step further Alstom is also planning to establish a global centre of excellence for microgrids on the site, aimed to help advance the development of microgrid technologies as part of the grid modernization project.

“We see this as a milestone project,” commented Schmitt. “We are implementing a microgrid at scale with an end to end business model, and it shows that there is a business case right now for this technology.”

The project will combine distributed renewable resources and energy storage assets to enable portions of the campus to become self-sufficient in generating, managing and storing electricity, and for the campus to be able to operate independently from the main grid in case of an outage due to extreme weather or other extraordinary events. Alstom will provide a comprehensive microgrid controller system prototype, or what it calls  “Utility-Customer Nexus in a Box”, supporting end-to-end functions. These will include microgrid islanding, synchronization and reconnection, protection, voltage, frequency, power quality management and dispatch and system resiliency.