Exelon’s (NYSE:EXC) Commonwealth Edison (ComEd), in a July 28 petition filed with the Illinois Commerce Commission, requested that the commission issue an order making certain rate-related findings supporting a distribution microgrid demonstration project and study.
The Bronzeville Microgrid Demonstration Project, to be built in the Bronzeville area of Chicago with the support of the U.S. Department of Energy (DOE) grants, would provide experience and learnings regarding the value and use of microgrids, as well as the use of targeted distributed energy resources (DER) in a distribution function to support microgrid operations, the company said.
Microgrids can mitigate the impacts of physical and cyber attacks on the grid, and may evolve to become the fundamental building blocks of a smart grid, ComEd said, adding, “[T]he project will move Illinois to the forefront of distribution system design and development.”
ComEd said that in preparation for the project, it undertook a comprehensive study to evaluate locations on its system where a microgrid could be located – that study resulted in the selection of Bronzeville as the project’s location. The study divided the company’s service territory into small sections and developed an overall resiliency metric for each section based on the existing power delivery infrastructure, existence of critical customers and facilities, as well as input from various stakeholders, the company said.
ComEd said that it paired the overall resiliency metric with geographical information to identify locations where a microgrid could address security and resiliency, with a focus on public good.
While the project is an integrated whole, its construction would proceed in two phases in order to allow ComEd to meet the requirements of the DOE Sustainable and Holistic Integration of Energy Storage and Solar PV (SHINES) grant before the entire project is completed, the company said.
As noted on DOE’s website, the SHINES program develops and demonstrates integrated photovoltaic (PV) and energy storage solutions that are scalable, secure, reliable, and cost-effective. SHINES is part of DOE’s Grid Modernization Initiative, which aims to accelerate the strategic modernization of the U.S. electric power grid and solve the challenges of integrating conventional and renewable sources, while ensuring a resilient energy system combining energy storage with central and distributed generation, according to the site.
ComEd said in its petition that Phase I of the project would focus on SHINES grant requirements and includes 2.5 MW of load, requires reconfiguration of one existing feeder along with associated cable reconnections and a 12-kV circuit extension to enable minimal microgrid configuration, and installation of at least 0.75 MW of solar PV and 0.5 MW/2 MWh of battery storage. ComEd said that it may also employ 3 MW of mobile diesel generators, which it already owns and uses for emergency purposes, for testing in the first phase.
The estimated total cost of the project in Phase I – net of the $4m DOE grant and $600,000 from project partners – is about $8m, the company said, adding that preparatory and planning work necessary to implement the SHINES grant is underway, and that the DOE-approved project plan and budget calls for the installation of the solar PV and battery to begin in 1Q18.
ComEd said that in Phase II of the project, it would add 4.5 MW of load along with about 7 MW of controllable generation resources. The company noted that it also plans to interconnect with the existing microgrid at the Illinois Institute of Technology in Phase II to achieve clustering.
The company said that it estimates that the cost of Phase II would be about $17m, and it may be significantly less, depending on the mix of DER incorporated and the outcome of the competitive DER procurement process that the company plans to conduct.
Once complete, the Phase II integrated DER would provide enough power to maintain service within the microgrid when it is islanded from the larger ComEd grid, the company said. When the larger delivery system serving the project area experiences a disruption, the project could be islanded from the larger grid, and its DER would keep power flowing to customers within the project area, the company said.
The portfolio of DER would include substantial “spinning” resources to maintain the 60 Hz frequency of the microgrid and ensure its stability, the company said, adding that that function would be fulfilled by gas and/or diesel generation assets. Additional generation units may also be required for “cold start” and ramping, but the ability of the microgrid to provide those capabilities in other ways will be studies, ComEd said.
The company noted that it is evaluating alternative ownership arrangements for the project’s controllable DER and solar PV to determine the most efficient option to meet project needs. ComEd said that it plans to conduct a competitive procurement process and will consider third-party ownership of those resources combined with a lease or another arrangement that would allow ComEd to use the DER as required for project operations. In that arrangement, any other DER output or benefits would be retained by the third party and could be used by that entity to power their facilities or be sold in the marketplace, the company said.
While the exact terms, structure, and length of such an arrangement is uncertain at this time, ComEd said that it would attempt to structure the arrangement to support the proposed 10-year project study period. However, if after the competitive procurement process ComEd determines that the cost of an arrangement with a third party would exceed the cost for ComEd to own the assets itself, or if other elements of the arrangement such as DER location are inefficient or impractical, then ComEd would purchase and own the project DER, the company said.
In that case, the company noted that it plans to operate those resources when not needed for a distribution reliability function of the project to reduce line losses and unaccounted for energy to the benefit of all ComEd customers; ComEd would continue to own and operate the facilities for their expected useful lives.
The company said that it would study the project beginning in 2019, when the Phase I SHINES assets are scheduled to become operational, and that it would track and measure the costs and benefits of the project over a study period of about 10 years.
ComEd said that it would use project data to evaluate and validate the analysis it used to select the Bronzeville neighborhood; evaluate the significance of the information gleaned by the metrics to determine whether the individual metrics are valid and quantifiable; and use the metrics to evaluate the impacts of the project.
Among other things, ComEd said that the current timetable for the SHINES grant anticipates ComEd submitting a report to DOE at the end of 2019.