Key Connections. By Merrill Smith and Dan Ton

Transcription

1 Key Connections By Merrill Smith and Dan Ton Digital Object Identifier /MPE Date of publication: 19 June ieee power & energy magazine 11mpe04-smith indd 22 M MICROGRIDS HAVE BEEN IDENTIFIED AS KEY components of the smart grid for improving power reliability and quality, increasing system energy efficiency, and providing the possibility of grid independence to individual end-user sites. The Microgrid Exchange Group, an ad hoc group of experts and implementers of microgrid technology, has defined a microgrid as a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island mode. Microgrids have been described by other organizations using similar definitions, including the key concepts of a U.S. Government work not protected by U.S. Copyright. july/august 2013

2 DIGITAL STOCK The U.S. Department of Energy s Microgrid Initiative system made up of multiple loads along with generation and the ability to island from the grid. Microgrids provide multiple benefits that include: enabling grid modernization and the integration of multiple smart grid technologies enhancing and easing the integration of distributed and renewable energy sources that help reduce peak load and also reduce losses by locating generation near demand meeting end-user needs by ensuring energy supply for critical loads, controlling power quality and reliability at the local level, and promoting customer participation through demand-side management and community involvement in electricity supply supporting the macrogrid by handling sensitive loads and the variability of renewables locally and supplying ancillary services to the bulk power system. Within the Office of Electricity Delivery and Energy Reliability (OE) of the U.S. Department of Energy (DOE), the Smart Grid R&D Program was established to accelerate the deployment and integration of the advanced communication, control, and information technologies needed to modernize the nation s electric delivery network. This modernization includes preparing the U.S. electric infrastructure to meet the challenges of the 21st-century economy. The Smart Grid R&D Program has two goals: to dynamically optimize grid operations and resources for a robust, flexible, and secure electric grid; and to fully integrate demand response and consumer participation into grid resource planning and operations. The program s microgrid activities supports the achievement of both of these goals. According to the DOE s September 2011 update of the Smart Grid Research and Development Multi-Year Program Plan: (available at the microgrid initiative has established the following 2020 performance targets for costs, reliability, system energy efficiencies, and emissions to advance these grid modernization goals: to develop commercial-scale microgrid systems (capacity <10 MW) capable of reducing [the] outage time of required loads by >98% at a cost comparable to nonintegrated baseline solutions (uninterrupted power supply plus diesel genset) while reducing emissions by >20% and improving system energy efficiencies by >20%. This article provides an overview of ongoing microgrid activities being undertaken by OE and its Smart Grid R&D Program. In addition, it discusses the process OE has undertaken to engage microgrid stakeholders to jointly identify the remaining areas in which there are R&D gaps and develop a plan to address those gaps. Ongoing Microgrid Activities The bulk of the DOE s microgrid R&D efforts to date have focused on demonstration activities to meet niche application needs, such as those for meeting peak load reduction, renewable energy mandates and directives, and energy surety and reliability at certain critical facilities, including military installations. These ongoing microgrid demonstration projects consist of lab- and field-scale R&D test beds, renewable and distributed systems integration (RDSI) projects for peak load reduction, select Smart Grid Demonstration Program (SGDP) projects funded under the American Recovery and Reinvestment Act of 2009 (ARRA) as part of OE s implementation of grid modernization, and assessment and demonstration projects jointly supported by the U.S. Department of Defense (DOD) and the DOE. OE is currently supporting nine RDSI projects with a total value exceeding US$100 million (with approximately US$55 million coming from the DOE). The two primary goals of these projects are to demonstrate at least 15% peak demand reduction at the distribution feeder or substation level through integrating distributed energy resources (DERs) and to demonstrate microgrids that can operate in both grid-parallel and islanded modes. These projects are proving out systems that can defer transmission july/august 2013 ieee power & energy magazine 23 11mpe04-smith indd 23

3 This article provides an overview of ongoing microgrid activities being undertaken by OE and its Smart Grid R&D Program. and distribution investments and upgrades by utilizing local assets (generation and load reduction) in an integrated fashion. They are also increasing the reliability of the local distribution system by adding elements that make it more stable and reconfigurable. Other benefits being realized from these projects include addressing vulnerabilities in critical infrastructure, managing peak loads, lowering emissions, using fuel resources more efficiently, and helping customers manage energy costs. These RDSI projects are progressing toward achieving the goals of at least 15% in peak demand reductions and the ability to island. Some, such as the Illinois Institute of Technology, Chevron/Santa Rita Jail, and Ft. Collins FortZED projects, have already realized or exceeded the 15% reduction goal. Under ARRA, SGDP has funded 16 smart grid regional demonstration projects to demonstrate emerging smart grid technologies and alternative architectures to validate business models and address regulatory and scalability issues. Among them, several projects are conducting demonstrations involving combinations of the following elements: renewable energy resources, distributed generation, energy storage, demand-side management, and charging schemes for plug-in electric vehicles. These projects include (but are not limited to) the Pacific Northwest Smart Grid Demonstration by Battelle Memorial Institute, which includes Portland General Electric s High Reliability Zone (a microgrid); the Energy Internet Demonstration by Pecan Street Project Inc. in Texas; and the Irvine Smart Grid Demonstration by Southern California Edison. Further information on the SGDP projects is available at ys=&project%5b%5d=2. There has also been a significant effort by national laboratories to produce microgrid designs, analyses, and demonstrations at test facilities and military bases. Lawrence Berkeley National Laboratory (LBNL) is teaming with American Electric Power (AEP), the University of Wisconsin, and Sandia National Laboratories (SNL) to apply Consortium for Electric Reliability Technology Solutions (CERTS) microgrid concepts in AEP s Dolan Technology When a Disturbance to the Utility Grid Occurs, the Automatic Disconnect Switch Enables the Facility to Island Itself from the Main Utility Grid and Independently Generate and Store Its Own Energy Utility Power Enters the Facility at the Point of Common Coupling PG&E Utility Interconnection or Point of Common Coupling and Static Disconnect Switch Five 2.3-kW Wind Turbines Facility Electric Load Two 1.2-MW Backup Diesel Generators Distributed Energy Resources Management System (DERMS) The DERMS Serves to Reduce Peak Demands During Normal Grid-Connected Operation or During a Demand Response Event 1-MW Fuel Cell Facility Electric Load 2-MW Advanced Energy Storage System 1.2-MW Rooftop Solar Photovoltaic System figure 1. Chevron Energy Solutions project at the Santa Rita Jail in Dublin, California, to demonstrate commercial application of a CERTS microgrid (used with permission). 24 ieee power & energy magazine july/august mpe04-smith indd 24

4 There has also been a significant effort by national laboratories to produce microgrid designs, analyses, and demonstrations at test facilities and military bases. Center at the Walnut Station Test Facility in Groveport, Ohio. The Sacramento Municipal Utility District, the Chevron Energy Solutions RDSI project (shown in Figure 1), and the DOD at Fort Sill and Maxwell Air Force Base are also applying CERTS microgrid concepts in field demonstrations. LBNL has developed the Distributed Energy Resources Customer Adoption Model (DER-CAM), an economic model for predicting and optimizing the capacity and minimizing the cost of operating distributed generation in microgrids. SNL has developed its Energy Surety Microgrid (ESM) methodology, which uses cost and performance data from military bases to develop approaches for implementing highreliability microgrids and to assist in planning for and analysis of the potential risks in future military and commercial projects. To date, 14 military bases have received assessments and/or conceptual microgrid designs using SNL s ESM methodology. From this work, SNL has developed a set of valuable lessons learned that, combined with its design methodology, provide a blueprint for future ESM microgrid implementation. The ESM design work was the springboard for a larger joint microgrid deployment effort on the part of the DOE, the DOD, and the U.S. Department of Homeland Security (DHS). This joint effort, known as a joint capabilities technology demonstration (JCTD), is the first of its kind for the DOE and will ultimately deploy three Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) microgrids. Five national laboratories Idaho, National Renewable Energy Laboratory, Oak Ridge National Laboratory (ORNL), Pacific Northwest National Laboratory (PNNL), and SNL supported by the DOE are playing a pivotal role in the SPIDERS deployment through their work on the microgrid designs, the cyber designs, and the development of a transition plan that can be used to design and deploy microgrids at additional military facilities and in the private sector. The three SPIDERS microgrids will be deployed in phases at Joint Base Pearl Harbor-Hickam (Hawaii), Fort Carson (Colorado), and Camp Smith (Hawaii), respectively. The first phase, at Pearl Harbor-Hickam, has completed successful technical and operational demonstrations. A key element of SPIDERS is standardization of the design approach, contracting, installation, security, and operation of these microgrids to support future applications. Other work at the national laboratories is also supporting the microgrid effort. ORNL s Distributed Energy Communications & Controls laboratory is developing controls for inverter-based DERs to provide local voltage, power, and power quality support for the ORNL campus distribution system. On the simulation side, PNNL has been developing GridLAB-D as a distribution system simulation tool that integrates grid operations at several levels, including microgrids. As OE moves forward with microgrid R&D, it is coordinating the national laboratories efforts on microgrids so they will be more cohesive and unified. The labs will be working on three major tasks. The focus will be on: developing use cases (based on existing microgrids) to define the performance requirements and technology specifications of microgrids performing cost and benefit analysis to identify highimpact R&D for additional investments creating integrated tool sets for developing conceptual and preliminary designs and controls and operations architectures. In addition to meeting individual niche applications, the various DOE demonstrations also field-prove capabilities of current technologies and unveil lessons learned, challenges, and needed but unmet capabilities. Current technologies will clearly not be enough to meet the 2020 performance targets established by the DOE for microgrids. As part of its continuing effort to engage stakeholders in joint planning and implementation of R&D activities, the Smart Grid R&D Program convened two microgrid workshops, in 2011 and 2012, to seek stakeholder input on key areas for R&D and performance baselines, targets, and actionable plans. This input was incorporated into the DOE s 2012 Smart Grid Research and Development Multi-Year Program Plan to guide current and future DOE R&D efforts in microgrids (see Figure 2). Microgrid Workshops The DOE held its first microgrid workshop on August 2011 in San Diego, California; a follow-up workshop was held on July 2012 in Chicago. The purpose of the first workshop was to convene experts and practitioners to assist the DOE in identifying and prioritizing R&D areas in the field of microgrids. The second workshop was held in response to path-forward discussions that called for sharing lessons learned and best practices for system integration from existing projects in the United States (including military microgrids) and elsewhere. In addition, the purpose of the second workshop was to delve more deeply into R&D topics gathered from the first workshop and july/august 2013 ieee power & energy magazine 25 11mpe04-smith indd 25

5 The DOE s Smart Grid R&D Program considers microgrids to be a key building block for a smart grid and has established microgrid R&D as a key area of focus. subsequently determine system integration gap areas and functional requirements. The 2011 Workshop Two tracks were organized to address the potential cost reduction of major microgrid components and subcomponents. One track focused on microgrid components, with separate sessions on switch technologies, control and protection technologies, and inverters and converters. The second track focused on microgrid systems, with separate sessions on standards and protocols, system design and economic analysis tools, and system integration. The 2012 Workshop A working list of system integration issues, categorized in the two areas of planning and design and operations and Workshops to Engage Stakeholders for R&D Planning Rescoping Lab AOPs to Address Workshop Priority R&D Topics FY14 Microgrid R&D FOA 2011 Workshop Affirmed DOE 2020 Targets and Defined R&D Areas for Component and System Integration Technologies 2012 Workshop Integrated R&D Areas (from 2011) Into Planning/Design and Operatons/Control and Prioritized R&D Topics in Each Use Case Development to Define Performance Requirements and Technology Specifications Cost and Benefit Analysis to ID High-Impact R&D for Investments Integrated Tool Sets for Conceptual/ Preliminary Designs Integrated Tool Sets for Controls and Operations Architecture In Synergy with Lab AOPs to Achieve Cost Parity for the Identified Microgrid Use Case figure 2. R&D pathway toward the DOE s 2020 microgrid performance targets. control, was presented for input from the attendees, based on their experience. This brainstorming session resulted in 12 R&D topics for discussion. For each topic, participants discussed four aspects: the current status of the technology, needs and challenges, the scope of the needed R&D, and R&D metrics. Conclusions from the breakout session discussions and the report-out presentations from the 2011 workshop were documented in the DOE Microgrid Workshop Report, available at 20Workshop%20Report%20August% pdf. The 2012 workshop program agenda with embedded presentation links is available at Table 1 lists the key R&D areas identified from the two workshops. Conclusions and the Path Forward The DOE s Smart Grid R&D Program considers microgrids to be a key building block for a smart grid and has established microgrid R&D as a key area of focus. A significant number of R&D needs and challenges have been identified for microgrids during the two workshops described above, with input from more than 170 experts and practitioners, representing a broad group of stakeholders in the United States, Canada, Europe, Japan, and Korea. At the two workshops, the scope of the R&D necessary to address the identified needs and challenges was outlined. The technical, economical, social, and environmental benefits that can result from successful development and deployment of microgrids became evident in the course of the workshop discussions and presentations. Engaging stakeholders and knowledgeable practitioners to obtain input on R&D needs is a key part of the R&D topic development process. With the input collected, the Smart Grid R&D Program will further refine R&D requirements so as to plan and develop a competitive 26 ieee power & energy magazine july/august mpe04-smith indd 26

6 table 1. Key R&D areas identified from the DOE s 2011 and 2012 microgrid workshops Workshop 2012 Workshop R&D Areas Components Systems Planning and Design Operations and Controls Switch Technologies Standards and Protocols System Architecture Development Legacy grid-connection technologies to enable connection and disconnection from the grid Requirements based on customer and utility needs Control and Protection Technologies Best practices and specifications for protection and controls; information models Reliable, low-cost protection Switches to handle full fault current Universal microgrid communications and control standards Microgrid protection, coordination, and safety System Design and Economic Analysis Tools Microgrid multiobjective optimization framework Designing an operations optimization methodology that takes uncertainty into account Definition of microgrid applications, interfaces, and services Open architectures that promote flexibility, scalability, and security Modeling and Analysis Performance optimization methods and uncertainty in the modeling and design process Steady-State Control and Coordination Internal services within the microgrid Interaction of the microgrid with utilities or other microgrids Transient State Control and Protection Transient state control and protection Inverters/Converters System Integration Power System Design Operational Optimization Topologies and control algorithms so that multiple inverters can operate in a microgrid Advanced power electronics technologies A common integration framework DC power Microgrid integration Operational optimization of a single microgrid Operational optimization of multiple microgrids funding opportunity announcement, subject to available DOE funds. The DOE s microgrid R&D initiative hopes to advance microgrids, in partnership with industry and research experts, from conception through R&D execution. For Further Reading U.S. Department of Energy. Information/fact sheets on the smart grid projects (including the smart grid demonstration projects) funded through the American Recovery and Reinvestment Act of [Online]. Available: smartgrid.gov/recovery_act/project_information U.S. Department of Energy. (2012, May 10). Smart grid R&D Program peer review June 7 8, [Online]. Available: U.S. Department of Energy. Smart grid research & development multi-year program plan: [Online]. Available: Update.pdf U.S. Department of Energy. (2011). Microgrid workshop report. [Online]. Available: Microgrid%20Workshop%20Report%20August% pdf U.S. Department of Energy. (2012). Microgrid workshop agenda and presentations. [Online]. Available: com/microgrid-2012/workshop_agenda pdf Sandia National Laboratories. SPIDERS: The smart power infrastructure demonstration for energy reliability and security. [Online]. Available: wp-content/gallery/uploads/spiders_fact_sheet_ p.pdf Biographies Merrill Smith is with the U.S. Department of Energy, Washington, D.C. Dan Ton is with the U.S. Department of Energy, Washington, D.C. p&e july/august 2013 ieee power & energy magazine 27 11mpe04-smith indd 27