Microgrid Institute Releases Report on
Multi-Zone Microgrid Optimization
DOE-Funded R&D Project Designs, Tests Microgrid Controls for Maryland Communities
:: FOR IMMEDIATE RELEASE ::
May 9, 2018, Montgomery County, Md.: On behalf of the project team, Microgrid Institute has released for public distribution the final technical report in the Olney Town Center Microgrid Control System R&D Project. The project, which included design, development, and testing of a control system for a multi-zone community microgrid, was supported by a grant from the U.S. Department of Energy (DOE), Office of Electricity, through the National Energy Technology Laboratory (NETL).
In the report, the project team presented the results of more than two years of research, development, and testing. Project results showed that a multi-zone microgrid control approach – managing distributed solar photovoltaics (PV), energy storage systems, and gas-fired combined heat and power (CHP) units in several independently islanding sub-systems – can effectively ensure the availability of resilient energy supplies in Mid-Atlantic communities.
Organized in four volumes, the 160-page report detailed technical design and configuration considerations for multi-zone microgrid systems; analysis of test results; and examination of regulatory and financial options for public-purpose microgrids in Maryland.
The Microgrid Institute-led project was one of seven that DOE supported in its competitive 2014 R&D funding program, “Microgrid Research, Development, and System Design” (FOA 0000997). The Olney Town Center project focused on research, design, development, and testing (in simulation) microgrid systems for Maryland communities, with Olney Town Center selected as the primary design-test area. In addition to technical factors, the project also examined regulatory and planning issues affecting potential for utility rate-base investments in Maryland public-purpose microgrids.
The project team was comprised of the following organizations:
Project objectives included designing a system capable of improving the test area’s System Average Duration Index (SAIDI) reliability performance by 98%; indefinitely sustaining critical services during major outage events; and improving average system energy efficiency factor and reducing its CO2 footprint by at least 20% -- at a life-cycle cost that is comparable to non-integrated standby generation and uninterruptible power supply (UPS) solutions.
As the final report explained, achieving the objectives at costs comparable to baseline options required a design and control strategy that would minimize capital costs and maximize capacity utilization. “A key design factor for the Project is the desire to avoid over-building generation and storage systems, and thereby to reduce the cost premium that typically accompanies highly resilient energy systems,” the report states. “Accomplishing this required optimizing system sizing and operations.” Project tests showed the size-optimized design – with a much smaller reserve capacity than is typically expected for such systems – would meet resiliency needs in almost all test cases, with noteworthy exceptions during low solar production periods accompanied by high customer loads.
The microgrid control system was built on Green Energy Corp’s open-source GreenBus distributed energy resource control platform. The project included development and integration of GreenBus applications to support system interoperability; low-latency messaging and secure transport; and customizable data automation and control capabilities. The GreenBus platform enabled development of a microgrid control architecture that includes multiple zones capable of autonomous operation (see Figure 1). This multi-zone microgrid control architecture – with master microgrid control at the fleet and zone level, interfacing with DER device controllers – accommodated the characteristics of a community with dispersed critical services and mixed overhead and underground distribution systems.
In the report, the project team presented the results of more than two years of research, development, and testing. Project results showed that a multi-zone microgrid control approach – managing distributed solar photovoltaics (PV), energy storage systems, and gas-fired combined heat and power (CHP) units in several independently islanding sub-systems – can effectively ensure the availability of resilient energy supplies in Mid-Atlantic communities.
Organized in four volumes, the 160-page report detailed technical design and configuration considerations for multi-zone microgrid systems; analysis of test results; and examination of regulatory and financial options for public-purpose microgrids in Maryland.
The Microgrid Institute-led project was one of seven that DOE supported in its competitive 2014 R&D funding program, “Microgrid Research, Development, and System Design” (FOA 0000997). The Olney Town Center project focused on research, design, development, and testing (in simulation) microgrid systems for Maryland communities, with Olney Town Center selected as the primary design-test area. In addition to technical factors, the project also examined regulatory and planning issues affecting potential for utility rate-base investments in Maryland public-purpose microgrids.
The project team was comprised of the following organizations:
- Microgrid Institute (prime contractor, project manager, and principal investigator)
- Green Energy Corp (microgrid control system R&D and development)
- North Carolina State University – FREEDM Systems Center (test design and execution)
- Schneider Electric (bi-directional inverter, engineering analysis)
- PEPCO Holdings (utility partner)
Project objectives included designing a system capable of improving the test area’s System Average Duration Index (SAIDI) reliability performance by 98%; indefinitely sustaining critical services during major outage events; and improving average system energy efficiency factor and reducing its CO2 footprint by at least 20% -- at a life-cycle cost that is comparable to non-integrated standby generation and uninterruptible power supply (UPS) solutions.
As the final report explained, achieving the objectives at costs comparable to baseline options required a design and control strategy that would minimize capital costs and maximize capacity utilization. “A key design factor for the Project is the desire to avoid over-building generation and storage systems, and thereby to reduce the cost premium that typically accompanies highly resilient energy systems,” the report states. “Accomplishing this required optimizing system sizing and operations.” Project tests showed the size-optimized design – with a much smaller reserve capacity than is typically expected for such systems – would meet resiliency needs in almost all test cases, with noteworthy exceptions during low solar production periods accompanied by high customer loads.
The microgrid control system was built on Green Energy Corp’s open-source GreenBus distributed energy resource control platform. The project included development and integration of GreenBus applications to support system interoperability; low-latency messaging and secure transport; and customizable data automation and control capabilities. The GreenBus platform enabled development of a microgrid control architecture that includes multiple zones capable of autonomous operation (see Figure 1). This multi-zone microgrid control architecture – with master microgrid control at the fleet and zone level, interfacing with DER device controllers – accommodated the characteristics of a community with dispersed critical services and mixed overhead and underground distribution systems.
Fig. 1: Multi-Zone Microgrid Overview
In a multi-zone community microgrid, critical loads in multiple areas – both adjacent and isolated – are supported with distributed energy resources (DER) and load-management systems. Separate interconnection systems for each zone enable safe formation of independent energy islands.
In a multi-zone community microgrid, critical loads in multiple areas – both adjacent and isolated – are supported with distributed energy resources (DER) and load-management systems. Separate interconnection systems for each zone enable safe formation of independent energy islands.
In addition to presenting the results of project R&D and testing processes, the final report also yielded recommendations to support future public-purpose microgrid developments in Maryland, including:
The report, Microgrid optimized resource dispatch for public-purpose resiliency and sustainability, (U.S. DOE Office of Scientific and Technical Information ID 1415998) is available for immediate download at: http://www.microgridinstitute.org/olneymicrogrid.html
Contact: Michael Burr, Director, Microgrid Institute
[email protected] / +1.320.632.5342
- Performing extensive community engagement to establish customer options and constraints, including defining customer resiliency requirements for critical energy loads;
- Validating gas-supply infrastructure to ensure supply resources can support CHP expansion in a given community; and
- Establishing community-customer financing and repayment options to support local resiliency projects whose cost savings alone are insufficient to justify general rate-base investments.
The report, Microgrid optimized resource dispatch for public-purpose resiliency and sustainability, (U.S. DOE Office of Scientific and Technical Information ID 1415998) is available for immediate download at: http://www.microgridinstitute.org/olneymicrogrid.html
Contact: Michael Burr, Director, Microgrid Institute
[email protected] / +1.320.632.5342
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