DG Case Studies by gjy28315


									                              Navigant Consulting Inc.

                      DG Network Case Studies for the
                    Massachusetts Technology Collaborative

                                Status Report (04/26/2004)


Navigant Consulting Inc. (NCI) has been retained by the Massachusetts Technology
Collaborative (MTC) to investigate distributed generation (DG) applications on electric
utility secondary network systems. The first phase of the investigation addressed the
development of uniform interconnection standards. On February 24, 2004, the
Massachusetts Department of Transportation and Energy (DTE) issued an order that
largely adopted the Model Distributed Generation Interconnection Standards and
Procedures Tariff prepared under Docket 02-38-B. The model tariff was developed via a
collaborative process involving representatives from industry, government, public
interest groups, electric utilities and other interested parties and stakeholders. The MTC
was a sponsor of the Collaborative, and retained NCI to provide independent technical

In its Order, the DTE set forth for further investigation and resolution several issues that
were not addressed in the Collaborative or for which participating parties could not reach
consensus. Two not addressed by the Collaborative included standby rates or charges
and the role of DG in electric utility distribution planning. The DTE will address the rate
issue in conjunction with NSTAR’s Standby rate filing and will separately address
planning issues under Docket 02-38-B, including whether the Collaborative could address
the role of DG in utility planning.

Related to the latter initiative is an assessment of the role of DG on utility secondary
network systems. Secondary networks systems are located mostly in urban centers such
as downtown Boston, and present interconnection challenges and hurdles not
encountered in interconnections to less complex radial distribution lines. Accordingly,
NCI is investigating the status of DG interconnections on network systems, including
case studies of existing or proposed projects in Massachusetts or other states. The
selection of DG case studies is based on a range of criterion, each of which is addressed in
the status report.

Interconnecting DG on network systems raises technical issues and hurdles which, if not
resolved, can thwart the development of a robust DG market in urban areas. The Model
Interconnection Tariff includes network interconnections, particularly for smaller,
inverter-based systems, but does not necessarily address specific interconnection
requirements for larger DG (i.e., above 7.5% of the network peak) or rotating machines.
Interconnection of DG on grid (as opposed to spot) networks raises greater challenges.

The Institute of Electric and Electronic Engineers (IEEE) has developed an
interconnection standard (IEEE Std. 1547). However, the IEEE standard applies solely to
radial or spot networks, but deferred on addressing grid interconnections due to the
inability to reach consensus on highly complex technical issues. Among other issues is
the need to prevent the inadvertent loss of network system load due to the presence of
DG. Secondary network systems are designed with several levels of redundancy to
ensure a very high level of reliability for critical urban or customer load. Electric utilities
consistently have raised concerns regarding the potential for DG to degrade network

The case studies presented herein address many of the issues raised above, including
solutions successfully employed for existing installation. We also address proposed
solutions for pending DG interconnections. The selection of DG candidates for the case
studies encompasses a range of criterion. The intent is to identify installations that meet
the criteria, particularly those that address interconnection requirements in
Massachusetts for a range of DG technologies. To identify candidate installations for the
case studies, NCI contacted utilities, DG suppliers, government agencies and other DG
stakeholders. We also reviewed literature and web sites to supplement or direct


Attachment I lists the companies and organizations NCI contacted to identify DG
installations on network systems. We focused first on those states – i.e., California, New
York, Texas and Massachusetts – that have adopted interconnection standards. NCI also
contacted acknowledged industry experts, including several who participated in the
Massachusetts Collaborative. We also reviewed industry literature, web sites, and
published reports, including technical reports prepared by IEEE and industry experts that
address network interconnection issues to assist in the preparation of selection criteria.
Attachment II lists DG units that are interconnected to secondary network systems. The
list was prepared based on contacts listed in Attachment I and our review of web site
data, and published documents. From our investigation, we found relatively few
interconnections where the DG unit operates in parallel with the electric grid. There are
several instances where synchronous generator provide backup for emergency purposes,
but operate only when the utility supplier is interrupted. Some may operate in parallel
for testing, but usually operate stand-alone when the utility supply is interrupted.
Notable exceptions include the Williams Building (GSA) in downtown Boston – the GSA
also proposes a similar project in the McCormick building in downtown Boston. The
other installations are mostly located in New York City and San Francisco. NCI also
identified a 200 kW fuel cell project proposed for downtown Manhattan, and is aware of
potential large application in downtown Boston. We also have attempted to contact other
organizations, but not have yet received callbacks or direct responses.


NCI has established criteria for selecting DG applications for case studies, summarized in
Attachment III. We do not expect any one project will meet each of the proposed criteria;
but rather, installations that meet most of the criterion may be the best candidates for case
study analysis. Once the criterion has been selected, NCI recommends the case study
address some or all of the topics listed in the report template included in Attachment IV.
The intent of the report, as outlined, is to address a wide range of institutional, technical,
regulatory, operating and performance, and economic issues for candidate technologies
interconnected to secondary spot or grid networks. Ideally, the case studies would
include existing inverter-based and rotating machines, large and small, operating in
parallel on both spot and grid network systems. Key findings, including lessons learned,
will be highlighted in the report, including the implications of these findings on future
DG network interconnections in Massachusetts, particularly issues that are not directly
addressed in the current interconnection tariff.


NCI is awaiting calls from some utilities and suppliers. While we are reasonably
confident the installations listed in Attachment II represent a good cross section of
existing DG projects, it will be instructive to determine if there are any other installations
that may not have been included in the list, particularly in the Northeast. Also, there may
be proposed DG installations that may be candidates for case studies. Once the list is
deemed complete, NCI will summarize survey results and work with the MTC to prepare
a draft case outline that it can present before the Process Committee in a meeting
scheduled for late May.
                                  Attachment I

                               Industry Contacts

Contact                                            Organization

Real Energy                                        DG Developer
E-Cubed                                            DG Experts & Analysts
Tecogen                                            DG Supplier
General Services Administration – New England      U.S. Government Agency
Department of Energy Resources (DOER)              Mass. Energy Agency
NYSERDA                                            NY Energy Agency
National Renewable Energy Lab (NREL)               U.S. Government Agency
Michigan Public Service Commission                 State Regulatory Agency
Texas Public Utilities Commission                  State Regulatory Agency
ERM (William Feero)                                Industry Expert
PTI/Shaw (Dave Smith)                              Industry Expert
Seattle City Light                                 Municipal Electric Utility
Sacramento Municipal Utility District              Municipal Electric Utility
Los Angeles Dept. of Water & Light                 Municipal Electric Utility
Oncor (Texas Utilities)                            Electric Utility (IOU)
Detroit Edison (DTE)                               Electric Utility (IOU)
Southern California Edison                         Electric Utility (IOU)
National Grid                                      Electric Utility (IOU)
Exelon                                             Electric Utility (IOU)
Fuel Cell Energy                                   DG Supplier
                                                                     Attachment II

                     Existing and Proposed DG Interconnections to Network Systems

Project Name                            Location          Utility        Contact/Source               Project Description               Comments
Coast Guard - Williams Building   Massachusetts         NSTAR     GSA-Roman Piaskoaki           30 KW PV, 75 KW Tecogen        Refer to GSA Report
Suffolk Country Jail              Massachusetts                   NECHP-Sean Casten
Mosconi Convention Center         California            PG&E      David Potter                  500 KW PV unit
Eilba Harris Building             Oakland, California   PG&E      Real Energy/Ruben Brown
199 Freemont St.                  San Fran.             PG&E      Real Energy/Ruben Brown
50 Beale St.                      San Fran.             PG&E      Real Energy/Ruben Brown
595 Market St.                    San Fran.             PG&E      Real Energy/Ruben Brown
717 5th Ave                       New York City         ConEd     Real Energy-Ruben Brown
Holiday Inn, Laugardia            New York City         ConEd     Real Energy-Ruben Brown                                      Induction Machine
St. Mary's Church                 Brooklyn              ConEd     Real Energy-Ruben Brown                                      Synchronous Machine
Kingsbrook Jewish Med. Ctr        New York City         ConEd     Real Energy-Ruben Brown                                      Not Operationing at this time
Luteran Medical Center            New York City         ConEd     Real Energy-Ruben Brown                                      Synchronous Machine
Montefiore                        Brooklyn              ConEd     Real Energy-Ruben Brown                                      Synchronous Machine
St. John's Hospital               Yonkers, NY           ConEd     Real Energy-Ruben Brown                                      Synchronous Machine
Sheraton Hotel Towers             New York City         PPL/ConEd Info. Obtained via Web Site   250-kilowatt fuel cell         Review Article
McCormack Federal Building        Boston                NSTAR     Roman Piaskoaki               10 KW PV, 200 KW Tecogen       Project is being Scoped
Confidential at this Time         Boston                NSTAR     N/A                           Details to come later
Peak Shaving/Load Control         Detroit               DTE       DTE                           Synchronous Machine > 1MW      4kV Network
Data Processing Centers           Dallas/Fort Worth     Oncor     Oncor                         5 Synchronous Machines > 1MW   Standby Only
                                    Attachment III

                           Case Study Selection Criteria

1. General

         Location - Urban versus Suburban – Preferably, one from each, as an urban
          unit may include secondary grid systems whereas suburban application
          usually are spot networks
         Application Type – One “Simplified” or “Expedited,” the other “Standard” or
         Jurisdiction – one in Massachusetts, one in state w/ significant DG penetration
          (e.g., California or New York), preferably a state in the northeast; none FERC
          wholesale as there are few, if any, DG network installations that fall under
          FERC’s jurisdiction
         Owner(s) – one government/public, the other private or utility-owned
         Funding – One fully private; the other subsidized (e.g., by supplier)
         Interconnection Standards – one in state w/ approved standards; the other
          proposed or not yet in place
         Export Sales – None expected, except Net Metering for DG <60kW
         Residential/Commercial – preferably, one of each (Commercial default);
          residential application on network likely difficult to locate

2. Interconnection Arrangements

         Spot versus Grid Network – Preferably, one on grid, one on spot
         Transformers/protectors - If Spot Network, 3 or more devices; if Grid Network,
          four primary feeder minimum
         Protection (Network Protectors - NWP) - one with time-delay, one
          instantaneous setting, if known
         Loads – One <15% of NWP composite load; the other >15%
         Primary System Upgrades – one w/ required T&D system upgrades; the other
          integrated w/ no major T&D upgrades
         SCADA/Communications/Monitoring – one system output monitored by
          SCADA or other real-time utility-compliant system; the other, no direct
3. Technology

        Size – One small (<25kW); one large (75kW or greater); could be in combination
         at one location; for example, the Williams building includes a 75kW induction
         generator and a smaller PV installation
        Standards – Must meet UL 1741, IEEE 1547 and IEEE 929, where applicable
        DG/Utility Interface – one inverter-based, one a rotating machine
        Type – Inverter: Fuel cell, PV, wind or capstone. Rotating: any induction or
         synchronous, including microturbines
        Commercial Status/Market Penetration – one commercially available, one a
                                    Attachment IV

                                Case Study Template

I.     Project Description
       a. Technology – PV, Fuel Cell, Microturbine, CHP, IC
       b. Size – Equipment rating & number of discrete units
       c. Equipment Type (Interconnection) – Inverter, induction, synchronous
       d. Loads – DG size as a function of load; load factor
       e. Location – City, electric utility, spot or grid network
       f. Mode of Operation – Parallel only or isolation mode option, including exports
          under Net Metering, if applicable
       g. Owner – Joint utility, manufacturer, government
       h. Technical and Operational Support – Third party operator, technical support
       i. Interconnection Agreement – Applicability with regard to proposed network

II.    Project History
       a. Project Concept - Evolution of project; options considered
       b. Electric Utility – Coordination, role and negotiations
       c. Expected Project Benefits – Reliability, cost reduction, power quality
       d. Funding Sources – If outside funding obtained; particularly for interconnection
          and control/monitoring systems
       e. Project Timing considerations - inception to implementation
       f. Permitting – State, federal & local, where applicable

III.   Interconnection Arrangement
       a. Spot or Grid Network –Description of utility primary and secondary systems
       b. Network Protector and Controls
       c. Modifications to Utility Grid – Protection, primary/secondary systems, and
          monitoring and controls, including feeders and substation equipment
       d. Electrical One-Line Diagram
       e. Monitoring and Control Systems – Customer and utility
       f. Isolation Mode – For critical load support
       g. Metering Arrangements – Including ownership
       h. Tariff Issues – Applicability of standby/back-up rates
IV.    Project Performance
       a. Technology – DG Performance
       b. Equipment Performance – Interconnection
       c. Protection Systems – Performance, including ability to properly clear under
          fault conditions
       d. Power Quality – PQ issues or problems encountered, if any
       e. Interconnection Operation & Maintenance – Activities performance and
          problems encountered
       f. Utility Issues – Feedback, concerns and recommendations from local electric
       g. Benefits – Were expected benefits/savings/reliability goals achieved?
       h. Proposed changes – To mitigate operating, protection or performance issues

V.     Standards
       a. IEEE – 1547
       b. IEEE – 929 – Photovoltaic (If applicable)
       c. ANSI/IEEE C57.12.44
       d. National Electric Safety Code
       e. National Electric Code (NEC)
       f. Other Codes and Standards

VI.    Summary & Lessons Learned
       a. Technology
       b. Permitting
       c. Performance
       d. Reliability
       e. Project Logistics
       f. Coordination and Communications w/ Local Utility, including planning

VII.   Findings & Conclusions
       a. Interconnection Performance
       b. Issues Addressed in Current DTE Tariff
       c. Suggested Revisions to Tariff Based on Case Study Results
       d. Interconnection Guidelines – IEEE and State
       e. Areas and Issues Needing Additional Study
       f. Next Steps

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