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Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

Evaluating the Role of 

Pre-Application Reports in 

Improving Distributed 

Generation Interconnection 

Processes

Zachary Peterson and Eric Lockhart

National Renewable Energy Laboratory

Technical Report

NREL/TP-7A40-71765

November 2018
NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, CO 80401

303-275-3000 • www.nrel.gov

Evaluating the Role of 

Pre-Application Reports in 

Improving Distributed 

Generation Interconnection 

Processes

Zachary Peterson and Eric Lockhart

National Renewable Energy Laboratory

Suggested Citation

Peterson, Zachary, and Eric Lockhart. 2018. Evaluating the Role of PreApplication Reports in Improving Distributed Generation Interconnection 

Processes. Golden, CO: National Renewable Energy Laboratory. 

NREL/TP-7A40-71765. https://www.nrel.gov/docs/fy19osti/71765.pdf.

Technical Report

NREL/TP-7A40-71765

November 2018
NOTICE

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable 

Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding 

provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy 

Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the 

U.S. Government.

This report is available at no cost from the National Renewable 

Energy Laboratory (NREL) at www.nrel.gov/publications.

U.S. Department of Energy (DOE) reports produced after 1991 

and a growing number of pre-1991 documents are available 

free via www.OSTI.gov.

Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795.

NREL prints on paper that contains recycled content.
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Acknowledgements

The authors thank the Department of Energy’s Solar Energy Technologies Office team for its 

support of this report. For providing comments on drafts of the report, the authors would also 

like to thank Gerry Bingham (Massachusetts Department of Energy Resources), Tom Key 

(EPRI), Francisco Flores-Espino (NREL), Jarett Zuboy (consultant), Kristen Ardani (NREL) and

Anna Ebers (DOE). 
iv

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List of Acronyms

DER distributed energy resources

DOER Department of Energy Resources 

DG distributed generation 

DSIRE Database of State Incentives for Renewables and Efficiency

FERC Federal Energy Regulatory Commission

FG&E Fitchburg Gas & Electric

IOU investor owned utility 

ISA Interconnection Service Agreement

kW kilowatt

MW megawatt

NEM net energy metering

POI point of interconnection

PV photovoltaic

SGIP Small Generator Interconnection Procedures

WMECO Western Massachusetts Electric Company
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Executive Summary

Several tools have emerged in recent years to increase data exchange and transparency in the 

distributed generation interconnection process with the goal of reducing interconnection costs. 

One example is pre-application reports. These reports are generated by a utility at the request of

prospective interconnection applicants to provide technical information about a specific point of 

interconnection. Formal pre-application report processes have been established in 12 states at the 

distribution system level as well as at the transmission level by the Federal Energy Regulatory 

Commission. 

These reports are a relatively low-cost method of informing applicants of grid conditions and 

potential interconnection limitations early in the interconnection process. Thus, this information 

may encourage interconnection in locations with little to no detrimental impact to the grid and 

low interconnection costs. Increasing transparency of these grid conditions may also enable 

applicants to better plan for interconnection costs and requirements, such as system 

modifications and complex engineering studies. By providing these benefits, pre-application 

reports are expected to reduce the number of canceled interconnection applications. This report 

evaluates this hypothesis by quantifying the impact pre-application report processes have on 

application approval rate. 

To evaluate this hypothesis this analysis uses utility-reported distributed generation 

interconnection data from four utilities in Massachusetts. The analysis considers a four-year time 

period before and a five-year period after pre-application report process were implemented. The 

results indicate that once pre-application reports were required for projects 500 kilowatts and 

larger the approval rate of applications increased by 24%. This suggests that pre-application 

reports may decrease the percentage of canceled projects. However, due to data and other 

limitations, these results do not necessarily connote causation.

This analysis is an important first step and a prerequisite for future analyses regarding the impact 

of pre-application reports. Rather than providing an inferential statistical analysis (e.g. a 

multivariate regression analysis) this report provides a descriptive statistical analysis that can be 

built upon with additional data. Other potential impacts also recognized during this analysis 

included reducing sunk costs and reducing the number of projects requiring a complex review. 

Collection of additional data would allow for forming more robust conclusions about these 

impacts in the future. Such data include circuit-level data, interconnection cost data, nationallevel data, and utility and developer attributes. These data provide necessary context to account

for interrelated factors while evaluating pre-application reports. Filling such knowledge gaps 

ultimately aids decision-makers (e.g. utility executives or regulators) in applying best practices 

within the industry. 
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Table of Contents

Acknowledgements ................................................................................................................................... iii

List of Acronyms........................................................................................................................................ iv

Executive Summary.................................................................................................................................... v

Table of Contents....................................................................................................................................... vi

List of Figures ........................................................................................................................................... vii

List of Tables ............................................................................................................................................. vii

1 Introduction........................................................................................................................................... 1

2 Current Pre-Application Report Practices ......................................................................................... 3

3 Massachusetts’ DER Interconnection and Regulatory Environment.............................................. 7

4 Data and Methods................................................................................................................................. 9

4.1 Data Selection and Processing ...................................................................................................... 9

4.2 Pathway Analysis........................................................................................................................ 10

5 Discussion........................................................................................................................................... 14

5.1 Pathway Results .......................................................................................................................... 14

5.2 Data Needs for Further Analysis................................................................................................. 15

6 Conclusions ........................................................................................................................................ 18

References................................................................................................................................................. 19

Appendix A. National Grid Pre-application Request ...................................................................... 21

Appendix B. DOER Monthly Interconnection Reporting Raw Data Fields ................................... 22

Appendix C. DOER Interconnection Data Cleaning........................................................................ 25

Appendix D. Massachusetts Interconnection Process .................................................................. 26
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List of Figures 

Figure 1. Map of states with formal pre-application processes (as of January 2018)................................... 3

Figure 2. Massachusetts IOU total installed NEM PV capacity, 2011–2017 ............................................... 8

Figure 3. Percentage of DG applications submitted to each utility, January 2009 – April 2018.................. 9

Figure 4. Analyzed interconnection application pathways......................................................................... 11

Figure 5. Interconnection pathways for projects 500 kW and larger with no pre-application report 

(N=515, January 2009-May 2013)......................................................................................... 12

Figure 6. Interconnection pathways for projects 500 kW and larger with a pre-application report (N=928, 

May 2013-April 2018) ........................................................................................................... 12

Figure 7. Changes in percentages of applications along each pathway after pre-application report 

processes were implemented (percentage in the pre-application case minus percentage in the 

no-pre-application case) for projects 500 kW and larger....................................................... 13

List of Tables 

Table 1. Alignment with FERC SGIP Pre-Application Report Criteria ....................................................... 5

Table 2. State and Federal Fees and Timelines for Pre-Application Reports............................................... 6

Table 3. Massachusetts Utility Characteristics, 2017 (U.S. Energy Information Administration 2017)...... 7

Table 4. Massachusetts Interconnection Project Review Paths.................................................................. 10

Table 5. Pathway Analysis Summary for Projects 500 kW and Larger...................................................... 13

Table 6. Year-to-Year Change in Percentage of Approved Applications................................................... 15
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1 Introduction

The spread of distributed energy resources (DERs), in particular solar photovoltaics (PV), has 

led to rapid changes in the U.S. electric grid. Interconnecting these resources has been a 

challenging process for utilities, customers, and project developers. For utilities a common result 

of this rapid expansion is longer application processing timelines and increased expenses. These 

challenges can put a strain on customer relationships and hinder utility compliance with

regulatory timelines for processing applications. Effective and up-to-date interconnection 

processes assist utilities with efficiently integrating DERs while maintaining safe, reliable, and 

affordable service. In addition, streamlined interconnection processes can reduce the financial 

resources and time required for utilities to interconnect DERs with the grid (Ardani and Margolis 

2015). Uniform interconnection standards, hosting capacity maps, and pre-application reports are 

a few examples of emerging practices in the industry to improve interconnection processes.

A pre-application report provides technical information about a specific point of interconnection 

(POI) on a utility’s distribution or transmission system. These reports are generated by a utility at 

the request of a prospective interconnection applicant, before an interconnection application is 

submitted. Appendix A shows an example pre-application request form from National Grid. The 

information provided in a pre-application report is based on data readily available to the utility

but typically unknown to applicants. For example, the report might note the total generation 

capacity currently in the interconnection queue for the circuit or preexisting system constraints.

This information enables interconnection applicants, such as PV project developers, to become 

aware of potential interconnection limitations or system upgrade costs early in the application 

process, before making significant financial investments. In the absence of more robust tools like 

hosting capacity maps or portals with on-demand circuit information, pre-application reports 

help provide this transparency.

Without the transparency provided by tools like pre-application reports, project developers may 

resort to submitting multiple, speculative applications to determine the best POI (Coddington et 

al. 2012). These additional applications consume excessive time and resources on the part of 

developers and the utility staff who process the applications. If applicants are aware of 

conditions that may trigger detailed studies or system modifications in advance, they may be able 

to avoid problematic locations. If the location cannot be changed, the developer can still make a 

more informed decision about whether or not to pursue the project before initiating the 

application process. Thus, it logically follows that pre-application report processes help reduce 

the number of canceled applications, whether they are speculative or due to overburdening 

unexpected interconnection costs. Although anecdotal evidence suggests that pre-application 

report processes provide benefits to utilities and interconnection applicants, the impacts have yet 

to be quantified (Bingham 2018).

This report analyzes the impacts of pre-application reports using utility-reported data on solar PV 

interconnection applications from investor-owned utilities (IOUs) in Massachusetts. In 

particular, it focuses on large PV projects (500 kilowatts [kW] and larger). Section 2 provides an 

overview of pre-application reports and how they are being applied in the United States. Section 

3 summarizes the Massachusetts regulatory environment to establish context for the data used in 

the analysis. Section 4 describes data collection, processing, and limitations as well as the
2

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analysis process. Finally, Sections 5 and 6 provide discussion and conclusions, including 

suggestions for future study.
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2 Current Pre-Application Report Practices 

Pre-application reports originated in California in 2012 at the distribution-system level. As of 

January 2018, 11 additional states have published formal rules for pre-application report 

processes.1 The Federal Energy Regulatory Commission (FERC) also enacted pre-application 

report processes at the transmission level through Order 792 (FERC 2013). Figure 1 shows the 

states that have implemented pre-application processes as of January 2018. 

Figure 1. Map of states with formal pre-application processes (as of January 2018)

Pre-application report processes vary from state to state, but the majority align with those 

established by the Small Generator Interconnection Procedures (SGIP) mandated by FERC 

Order 792. Typically, a potential interconnection applicant must submit a formal application 

(e.g., see Appendix A) requesting a pre-application report and provide basic information for the 

proposed project such as location, design capacity, and technology type. The utility then uses 

these inputs and preexisting system data to produce the report. The SGIP identifies 13 criteria for 

utilities to include in the pre-application report, assuming the data are readily available (FERC 

2013). 

1) Total capacity (in megawatts [MW]) of substation/area bus, bank, or circuit based on 

normal or operating ratings likely to serve the proposed POI 

2) Existing aggregate generation capacity (in MW) interconnected to a substation/area bus, 

bank, or circuit (i.e., amount of generation online) likely to serve the proposed POI

 1

This is based on a review of available state interconnection standards and regulatory proceedings conducted in 

January 2018. It does not include informal mechanisms, or states with utilities that offer this tool voluntarily. 
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3) Aggregate queued generation capacity (in MW) for a substation/area bus, bank, or circuit 

(i.e., amount of generation in the queue) likely to serve the proposed POI.

4) Available capacity (in MW) of substation/area bus or bank and circuit likely to serve the 

proposed POI (i.e., total capacity less the sum of existing aggregate generation capacity 

and aggregate queued generation capacity).

5) Substation nominal distribution voltage and/or transmission nominal voltage, if 

applicable.

6) Nominal distribution circuit voltage at the proposed POI.

7) Approximate circuit distance between the proposed POI and the substation.

8) Relevant line section(s) actual or estimated peak load and minimum load data, including 

daytime minimum load and absolute minimum load, when available.

9) Number and rating of protective devices and number and type (standard or bi-directional) 

of voltage regulating devices between the proposed POI and the substation/area. Identify 

whether the substation has a load tap changer.

10) Number of phases available at the proposed POI. If a single phase, distance from the 

three-phase circuit.

11) Limiting conductor ratings from the proposed POI to the distribution substation.

12) Whether the POI is located on a spot network, grid network, or radial supply.

13) Based on the proposed POI, existing or known constraints such as, but not limited to, 

electrical dependencies at that location, short circuit interrupting capacity issues, power 

quality or stability issues on the circuit, capacity constraints, or secondary networks.

The required criteria for pre-application reports in most states aligns with the SGIP. 

Table 1 shows how the report criteria requirements for each state compared to the 13 criteria 

required by the SGIP.
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Table 1. Alignment with FERC SGIP Pre-Application Report Criteria

FERC SGIP Pre-App Criterion CA IA IL NC OH SC VT RI NY MA NH OR No. of 

States

Existing Generation Capacity Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No 10

Queued Generation Capacity Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No 10

Distribution Circuit Voltage Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No 10

Number of Phases Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No 10

Substation Distribution Voltage Yes Yes Yes Yes Yes Yes No Yes No Yes No No 8

Total Capacity Yes Yes Yes Yes Yes Yes Yes No Yes No No No 8

Circuit Distance Yes Yes Yes Yes Yes Yes Yes No Yes No No No 8

Peak/Minimum Load Data Yes Yes Yes Yes Yes Yes Yes No Yes No No No 8

Constraints Yes Yes Yes Yes Yes Yes Yes Yes No No No No 8

System Configuration Yes Yes Yes Yes No Yes No Yes No Yes No No 7

Protective Devices Yes Yes Yes Yes Yes Yes Yes No No No No No 7

Limiting Conductor Ratings Yes Yes Yes Yes Yes Yes Yes No No No No No 7

Available Capacity Yes Yes Yes No Yes No Yes No No No No No 5

SGIP Criteria Adopted 13 13 13 12 12 12 11 7 7 6 0 0

Most states require a modest fee (typically ranging from $300 to $750) to compensate the utility

for the time taken to prepare the pre-application report. Timelines for producing the reports vary 

from 10 to 20 business days. For comparison, the FERC SGIP mandates a $300 fee and a 20-day 

timeline. New Hampshire and Oregon have less formal processes, providing utilities more 

flexibility in response time and fee structure.

Table 2 shows the fees and timeline for each state with pre-application report processes.
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Table 2. State and Federal Fees and Timelines for Pre-Application Reports

State Fee ($) Timeline (business days)

CA 300 10

IA 300 20

IL 300 20

MA 0 10

NC 300 10

NH -- --

NY 750 10

OH 300 10

RI 0 10

VT 300 10

OR * --

SC 500 20

FERC 300 20

-- None specified 

* Per OR legislation: "A person requesting information [under section (1)] 

must reimburse the public utility for the reasonable costs of gathering and 

copying the requested information."

Some states have expanded the role of pre-application reports. In California, applicants can 

purchase multiple supplementary pre-application reports, containing more detailed information,

in addition to the standard report.

2 Although pre-application reports are typically an optional 

step, in Rhode Island and Massachusetts they are required for projects of 500 kW or larger. The 

Massachusetts IOUs have provided monthly data on distributed generation (DG) interconnection 

applications to the Massachusetts Department of Energy Resources (DOER) since 2009, which 

appear to be the only detailed data available on interconnection processes completed from the 

beginning of the application process to the end (i.e., cancelation or an Interconnection Service 

Agreement [ISA]). These data provide an opportunity for deeper analysis of the interconnection 

process in Massachusetts.

 2 An example of the information included in these reports can be found here: 

https://www.pge.com/includes/docs/pdfs/b2b/interconnections/pre-app-request-guide.pdf.
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3 Massachusetts’ DER Interconnection and

Regulatory Environment

Massachusetts has operated in a restructured electric utility market since 1997 (DOER 2002). 

Transmission and distribution are managed primarily by the state’s IOUs, while generation falls 

to competitive suppliers. Massachusetts has four major IOUs: National Grid, NSTAR, Fitchburg 

Gas & Electric (FG&E), and Western Massachusetts Electric Company (WMECO). NSTAR and 

WMECO are commonly known by their parent company—Eversource Energy—and FG&E by 

its parent company—Unitil. Table 3 shows the average number of customers, volume of 

electricity sales, and revenue for the utilities in 2017. 

Table 3. Massachusetts Utility Characteristics, 2017 (U.S. Energy Information Administration 2017)

Revenue

(thousands)

Sales

(MWh) Customers

FG&E $2,932 13,613 20,547

WMECO $20,143 111,382 159,406

National Grid $101,185 537,847 758,932

NSTAR $103,324 708,089 659,241

MWh: megawatt-hour

Massachusetts has implemented several policy measures to support the growth of DERs, 

particularly PV. The state’s renewable portfolio standard, adopted in 2002 and expanded in 2008, 

requires 15% of electricity sales be generated from renewable energy sources by 2020 (Database 

of State Incentives for Renewables and Efficiency [DSIRE] 2017b). This percentage is required 

to grow by 1% each subsequent year, with no stated expiration date. In addition, a solar PV 

carve-out, established in 2010 and expanded in 2014, requires installation of 1,600 MW of solar 

by 2020. 

Incentives for DG growth also include Massachusetts’ net energy metering (NEM) policy. 

Established in 1982, this policy has been revised several times as caps have been reached and 

expanded. NEM is currently available to private generating facilities up to 2 MW and public 

generating facilities up to 10 MW (DSIRE 2017a). The aggregate NEM PV capacity for each 

distribution company is capped at 8% (public facilities) and 7% (private facilities) of the 

company’s highest peak load. PV deployment has grown significantly in this environment over 

the past decade (Figure 2).
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Figure 2. Massachusetts IOU total installed NEM PV capacity, 2011–2017

Massachusetts developed uniform interconnection standards for DG in the early 2000s

(Commonwealth of Massachusetts 2005). These standards have subsequently evolved, with the 

most recent reforms taking place in the early 2010s. These updates primarily focused on 

clarifying interconnection process requirements, timelines, and compliance monitoring. They 

also revised technical screens with the intention of allowing more applications to follow the 

expedited and simplified review pathways (Distributed Generation Interconnection Working

Group 2012). Massachusetts’ pre-application report process was approved by the Massachusetts 

Department of Public Utilities on May 1, 2013 (Bingham 2018). This mandate requires all 

projects of 500 kW or larger to receive a pre-application report before submitting a formal

interconnection application. For projects smaller than 500 kW, pre-application reports are an 

optional step in the interconnection process.

0

100

200

300

400

500

600

700

800

900

2011 2012 2013 2014 2015 2016 2017

Capacity (MW) 

FG&E NG NSTAR WMECO
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4 Data and Methods

This analysis uses Massachusetts DOER interconnection process data to explore the impacts of 

pre-applications on interconnection outcomes. Section 4.1 describes the data used, and Section 

4.2 describes the analysis methods.

4.1 Data Selection and Processing

The extensive Massachusetts DOER data on proposed projects—including project 

characteristics, POI characteristics, and review requirements—enable quantification of the 

impact of pre-application reports. These data are submitted in a standard template, aggregated,

and then posted on a DOER-hosted website (DOER 2018). The compiled data cover nearly 8,000

DG applications (~5.8 GW) submitted between January 2009 and April 2018. Figure 3 shows the 

percentage of DG applications submitted to each utility in that timeframe.

Figure 3. Percentage of DG applications submitted to each utility, January 2009 – April 2018

The utility-reported data for each application include information such as the application date, 

project design capacity, POI location, studies completed, and project status (see Appendix B for 

a full list of data included). These data were cleaned, mainly to standardize inputs and reduce 

ambiguity. For instance, the fuel types “Solar and battery” and “PV and battery” were combined.

Appendix C describes the data cleaning process.

The analysis was confined to PV projects (93% of applications) and PV-plus-battery projects 

(2% of applications), which ranged in size from 1.8 kW to 10 MW. The full data set included 

generator types such as wind, natural gas, and anaerobic digesters. Focusing on PV and PV-plusbattery projects reduces the number of potential factors affecting the results (e.g. differences due 

to technology characteristics). The raw data were grouped into four project status categories: 

Authorized, Process Complete, In-Progress, and Canceled. Projects in the Process Complete 

category had received an ISA but had not been authorized yet. For the purposes of this analysis,

these projects provided enough clarity on the progression through the interconnection process to 

be coded together with Authorized projects. Because the outcomes of the In-Progress 

applications were uncertain, the projects in this category were omitted from the analysis.

29%

55%

9%

7%

NSTAR National Grid WMECO Fitchburg
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4.2 Pathway Analysis

This analysis evaluates the hypothesis that pre-application report processes decrease the 

percentage of canceled projects. The first part of this analysis identifies the different review 

pathways an interconnection application can take before and after the pre-application report 

processes have been implemented. These pathways differ in complexity depending on the 

requirement of an impact study, detailed study, and/or system modification. The applications 

were tracked from start to finish to determine the percentage of projects eventually reaching 

either ISA or cancellation through these pathways. The results from these scenarios were 

analyzed to determine the effect pre-application reports had on application approval rate. 

The pathways were identified based on Massachusetts’ Standards for Interconnection of 

Distributed Generation (National Grid 2016). Appendix D provides a detailed flow chart of how 

applications proceed through the process. Applications submitted to the IOUs fall into three 

separate review pathways based on various system characteristics: Simplified, Standard, or 

Expedited (Table 4). The DOER data excludes projects undergoing the Simplified process, so 

only the Expedited and Standard review pathways were included in this analysis. 

Table 4. Massachusetts Interconnection Project Review Paths

Simplified Expedited Standard

PV and other inverter-based 

technologies served by radial 

systems, 15 kW or less 1-

Phase or up to 25 kW 3-Phase 

Inverter-based systems greater than 15 

kW 1-Phase or greater than 25 kW 3-

Phase and other systems of all sizes that 

are served by radial systems and meet 

other requirements

All projects not eligible 

for simplified or 

expedited review, 

including all systems on 

networks

Figure 4 shows the potential pathways analyzed. Prior to submitting an application, applicants 

may or may not request a pre-application report. Applications then follow either the Expedited 

pathway or the Standard pathway.

3 Applications following the Expedited pathway can reach 

agreement, be canceled, or be identified as needing a system modification, which is followed by 

either agreement or cancelation. For the Standard pathway, all applications receive an impact 

study. Four options can follow the impact study: cancelation, agreement, detailed study, or 

system modifications without detailed study. Applications needing system modification but no 

detailed study can be canceled or reach agreement. Projects requiring detailed study can either 

reach agreement, be canceled, or require system modification. Finally, these projects can either 

be canceled or reach agreement after system modification.

 3 In reality, projects can move from the Expedited to the Standard process as well. The DOER data only noted the 

final track each application followed, so that pathway was excluded for this analysis. 
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Figure 4. Analyzed interconnection application pathways

The DOER data set does not directly identify which applications received a pre-application 

report. However, because the pre-application process was implemented May 1, 2013, and all 

projects 500 kW and larger must receive a pre-application report, applications for projects of that 

size submitted after that date were assumed to have received one. Conversely, applications 500 

kW and larger submitted before that date were assumed not to have received one. Applications 

for projects smaller than 500 kW were subject to uncertainty because pre-application reports 

were optional for these projects. As a result, the analysis focused on projects 500 kW and larger 

and segmented the analysis into two subsets:

• Projects 500 kW or larger without a pre-application report (submitted on or before May 

1, 2013): 515 applications, 822 MW

• Projects 500 kW or larger with a pre-application report (submitted after May 1, 2013): 

928 applications, 1,673 MW

Figure 5 shows the percentages of the 515 analyzed applications without a pre-application report

following each pathway to agreement or cancelation: 67% underwent Expedited review, and 

33% underwent Standard review. In total, 67% of the projects within this group were canceled, 

while 33% reached an ISA. In addition, 39% of these projects required system modifications, but 

only 6% required a detailed study. Applications submitted under the Simplified pathway but later 

transitioned to an Expedited or Standard review are included in the data.

Figure 6 shows the percentages of the 928 analyzed applications with a pre-application report. 

Compared with the subset of applications with no pre-application report, a lower percentage of 

applications in the subset with a pre-application report underwent Expedited review (40% vs. 

67%) and a higher percentage underwent Standard review (60% vs. 33%). The subset with a preapplication report also had a higher percentage reaching agreement (57% vs. 33%), a lower 

percentage being canceled (43% vs. 67%), and higher percentages requiring system 

modifications (64% vs. 39%) and detailed study (14% vs. 6%).
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Figure 5. Interconnection pathways for projects 500 kW and larger with no pre-application report 

(N=515, January 2009-May 2013)

Figure 6. Interconnection pathways for projects 500 kW and larger with a pre-application report 

(N=928, May 2013-April 2018)

Figure 7 breaks out how all the pathway percentages changed after pre-application report 

processes were implemented (calculated as the percentage in the pre-application case minus the 

percentage in the no-pre-application case). The percentage of projects undergoing Expedited 

review decreased by 27% after pre-application reports were implemented, and the percentage of 

projects undergoing Standard review increased by 27% accordingly. Overall the percentage of 

projects that reached agreement rather than cancelation increased 24% after pre-application 

reports were implemented, while the percentage of projects requiring a detailed study increased 

8%, and the percentage requiring system modification increased 25%. Table 5 summarizes the 

results from Figure 5, Figure 6, and Figure 7.
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Table 5. Pathway Analysis Summary for Projects 500 kW and Larger 

Without preapplication report

(%)

With preapplication 

report (%)

Difference

(“with” minus

“without”)

(%)

Agreement 33.40 56.90 +23.50

Canceled 66.60 43.10 -23.50

Impact Study 33.01 60.34 +27.34

System Modification 39.42 64.22 +24.81

Detailed Study 6.02 14.12 +8.10

Figure 7. Changes in percentages of applications along each pathway after pre-application report 

processes were implemented (percentage in the pre-application case minus percentage in the nopre-application case) for projects 500 kW and larger
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5 Discussion 

This section discusses the pathway results as well as data needed to enable further analysis.

5.1 Pathway Results

Pre-application reports processes were expected to decrease the percentage of canceled projects. 

The pathway analysis results support this hypothesis by demonstrating a significant (24%) 

decrease in the percentage of canceled projects after pre-application report processes were 

implemented. For decision-makers seeking to improve interconnection processes, this is a 

meaningful result to consider. However, these results do not inform if pre-application reports 

improve the overall quality of applications, or if they simply reduce the amount of speculative 

applications. Further, it is difficult to say definitively that this improvement was caused by preapplication reports because it could be attributed to a number of factors. For instance, 

technological advancements may have improved the utility’s ability to integrate DG, increasing 

the number of authorized projects. Similarly, lessons learned by project developers may have 

resulted in higher quality applications or improved processes for identifying optimal POIs

(unrelated to pre-application reports). Additionally, projects that were previously cost prohibitive 

due to interconnection costs such as system modifications could now be feasible with the rapid 

decrease in PV system costs in recent years. It is possible all of these factors have played some 

role, in addition to pre-application reports.

An evaluation of the year-by-year change in percentage of approved projects (Table 6) further 

suggests that multiple factors likely play a role in the improvement of application approval rate.

Table 6 illustrates how the percentage of approved applications increased (positive percentage) 

or decreased (negative percentage) from one year to the next. For example, the percentage of 

approved projects increased 9% from 2009 to 2010, but decreased 21% from 2010 to 2011. 

Overall, the change in the percentage of approved applications varies widely from year to year. 

No significant trend is apparent for how approval rate is changing in the years prior to preapplication reports as the change in approved projects varies from positive to negative. In the 

years following pre-application report implementation, the change in approved projects is 

positive in all but one case. This continuous improvement in the application approval rate may be 

correlated to pre-application reports, but there is not enough evidence to suggest causation. 
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Table 6. Year-to-Year Change in Percentage of Approved Applications 

Year to Year Change

2009 – 2010 +9%

2010 – 2011 -21%

2011 – 2012 -9%

2012 – 2013 +10%

2013 – 2014 +4%

2014 – 2015 -5%

2015 – 2016 +4%

2016 – 2017 +11%

2017 – 2018 +14%

The pathway analysis also highlighted how pre-application processes may be impacting the 

percentage of projects following each distinct review pathway. In the four years prior to preapplication reports, 67% of applications for projects 500 kW and larger underwent expedited 

review (33% requiring standard review), but this fell to 40% (60% standard review) in the five 

years following pre-application report implementation. The percentage of applications requiring 

detailed study and system modifications increased by 8% and 25%, respectively, following preapplication report implementation. A variety of factors may have contributed to these shifts 

within the review pathways, such as increasing DG penetration or changes to review protocols.

Thus, these results may or may not be directly caused by pre-application reports. By increasing 

grid transparency and encouraging interconnection at locations with little to no detrimental

impact to the grid and low interconnection costs, it logically follows that pre-application reports

may decrease the percentage of applications requiring a system modification or complex 

engineering review. However, the data do not reflect this trend—both the percentage of system 

modifications and detailed studies increase. The number of factors that impact the review 

pathway an application follows makes the direct impact of pre-application reports unclear. 

Future analyses may consider investigating this relationship further. 

In-depth engineering studies increase the financial burden and processing time required from the 

utility and customer. If pre-application reports are increasing or decreasing the number of 

projects that typically need an in-depth engineering study, this would have an impact on 

interconnection costs. Similarly, by reducing the number of canceled projects, the sunk costs 

associated with canceled applications would also be reduced. The data considered lacked 

sufficient information to investigate these possibilities. Thus, a direct evaluation of preapplication report impact on interconnection costs was excluded in this analysis. The following

section discusses specific data points that may help with analyzing the impact of pre-application 

reports on interconnection costs and other aspects of the interconnection process. 

5.2 Data Needs for Further Analysis

This analysis represents a first step in the process of analyzing the impact of pre-application 

reports. The requirement for pre-application reports created a good natural experiment, and the 

pathway analysis here provides initial insights into what changes followed at a high level. 
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However, as more decision-makers consider requiring pre-application reports, they may benefit 

from further studies that seek to more precisely establish a causal relationship between the preapplication reports and the outcome observed here, controlling for other potential factors. This 

section discusses opportunities to make those more causal linkages and would apply to decisionmakers who are considering pre-application report requirements or other similar interventions.

The ideal approach to a complex question like this one would be to run a well-designed 

regression to carefully assess how a variety of factors influence the outcomes, such as those 

Massachusetts stakeholders were seeking by instituting mandatory pre-application reports for 

projects above 500 kW. The data that DOER collected and made available are an important first 

step towards a more robust data set that would facilitate more detailed analysis, but it is missing 

a few types of information. These gaps create a selection bias that makes effective regression 

analysis more challenging. 

In this analysis, the selection bias likely skews the results to improve the approval rate after preapplication reports were implemented. For example, if a developer obtains three pre-application 

reports for three different circuits at the same time and decides on that basis to target one of the 

three, the data set only shows the one application that went ahead. There would be no data 

linking all of the pre-application reports with the application that proceeded. Similarly, if the 

same developer obtained multiple pre-application reports for a given circuit over time, there 

might be learning that is occurring at the developer about interconnection trends. This learning 

may inform future project design decisions but cannot be observed in the data as it is currently 

structured. In either of those cases, the developer may also choose to re-apply with a differently 

specified project that is not flagged as a revised application with reference to its original 

application. 

Two primary sources of these gaps are 1) a lack of data identifying if an application received a 

pre-application report, and 2) a lack of data linking applications to the developers that submit 

them. Another related potential data point would note if the project is a revision to a prior project

that was deemed to be a costly stress on a given circuit (i.e., a field that asks if a given 

application is a revision of a previous application). These data would likely need to be 

anonymized with a unique identifier in some way. 

The additional data could be combined with several other categories of contextual information to 

more properly control for background factors that are valuable to control for in a regression 

analysis of pre-application report impact. Some of the data could be provided by an entity such 

as DOER, while others may require desk research or other sources. In addition to state-specific

contexts and drivers for the DER industry, there are several categories of expanded data that 

would support effective analysis of pre-application reports: 

1. Circuit-level data: Circuit information such as hosting capacity, voltage, and number of 

phases may aid in understanding why projects are integrated or canceled. While circuit 

conditions are dynamic, a snapshot of these at the time an application is submitted in 

conjunction with the project characteristics and can provide informative data. This could 

take a number of forms depending on data availability and regulatory requirements. As 

more jurisdictions pursue more expansive locational value methodologies, that 
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information could be pulled into this analysis. Utilities are the primary sources for this 

information.

2. Utility and developer attributes: For both utilities and developers, information that can 

help assess learning over time would be a useful variable to control for in this analysis. 

For example, changes in a given utility’s staffing levels or the amount of resources it can 

dedicate to interconnection processing could impact interconnection application results 

and costs. Data identifying the amount of resources (time and money) put towards 

interconnection applications over time can help identify when learning may be occurring. 

3. Interconnection costs: Project-level cost information for system modifications and 

engineering studies would assist in improving project planning processes. Ideally, this 

information would be provided by utilities and developers. Through analysis of this data

the relative uncertainty of these costs may be reduced. While these costs are dependent 

on system conditions, this data could be useful when associated with the project 

characteristics and circuit characteristics when the application was submitted. Ultimately,

the data could be used to identify trends that may reduce financial risk for project 

developers, thus reducing overall interconnection costs. Increased clarity of the dynamics 

of interconnection costs may aid in quantifying the impact of pre-application processes.

4. National interconnection data: Ideally, all the above data points would be provided by 

multiple states with varying regulatory structures. Expanding this analysis to include data 

beyond the Massachusetts market would help to validate that the impacts of preapplication report processes are not limited by nuances within individual states and thus 

can be widely applied. Entities such as DOER could assist with compiling and publishing 

this data to provide a central access point and maintain data privacy.
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6 Conclusions

New methods are being pursued throughout the country to improve interconnection processes 

and the transparency of grid integration. Pre-application report processes are one such method 

that has been deployed in multiple states towards these ends. In theory pre-application report 

processes provide a relatively low-cost, low-effort method for improving the interconnection 

process. This report analyzes the impact pre-application reports have on improving application 

approval rate. 

The analysis found that pre-application reports are correlated with an increase in application 

approval rate.

4 Following the implementation of pre-application report processes, the percentage 

of projects 500 kW and larger being canceled decreased 24%. During the analysis timeframe a 

notable shift was also observed in the review pathways followed for projects 500 kW and larger. 

The percentage of projects following the expedited review path decreased by 27%. The 

percentage of projects requiring a system modification and detailed study both increased by 25% 

and 8% respectively. This trend towards applications requiring more complicated reviews may or 

may not be correlated with pre-application reports. Additional data and analyses are needed to 

better characterize this relationship. 

The analysis is unable to conclude direct causation between pre-application reports and the 

increased application approval rate. This is primarily due to the multitude of factors impacting 

application approval and gaps in available interconnection data. In particular, the data were 

subject to selection bias due to the fact that no data exist for when a project is canceled based on 

the information contained in a pre-application report prior to a formal application submission.

Data expanding upon the current set to clarify issues such as this can help to overcome these 

challenges. In addition, data such as utility/developer attributes and circuit-level data can expand 

the analysis to provide a more robust understanding of how pre-application reports and other 

measures are affecting the interconnection process. 

As the complexity of the grid continues to grow, so does the need to manage that complexity. 

Tools such as pre-application reports may aid in improving interconnection processes, but it is 

important to measure their impact in practice to verify they are resulting in the intended 

consequences. Decision-makers that wish to improve interconnection processes through 

evidence-based analysis require data that provide sufficient context and facilitate measurement 

of these tools. 

 4 There are also other factors that are correlated with application approval rate, such as maturity of the marketplace.
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References

Ardani, Kristen, and Robert Margolis. 2015. Decreasing Soft Costs for Solar Photovoltaics by 

Improving the Interconnection Process: A Case Study of Pacific Gas and Electric. Golden, CO: 

National Renewable Energy Laboratory. https://www.nrel.gov/docs/fy15osti/65066.pdf

Bingham, Gerry. 2018. “Pre-Application Report Analysis,” June 7, 2018.

Coddington, M., K. Fox, S. Stanfield, L. Varnado, T. Culley, and M. Sheehan. 2012. Updating 

Small Generator Interconnection Procedures for New Market Conditions. Golden, CO: National 

Renewable Energy Laboratory. NREL/TP-5400-56790. https://doi.org/10.2172/1060613.

DOER (Division of Energy Resources, Commonwealth of Massachusetts Office of Consumer 

Affairs and Business Regulation). 2002. 2000 Market Monitor: Electric Industry Restructuring. 

http://www.mass.gov/eea/docs/doer/electric-deregulation/mm3.pdf

DOER (Massachusetts Department of Energy Resources). 2018. Interconnection

https://sites.google.com/site/massdgic/home/interconnection

DSIRE (Database of State Incentives for Renewables & Efficiency). 2017a. Net Metering.

Accessed March 26, 2017. http://programs.dsireusa.org/system/program/detail/281

DSIRE (Database of State Incentives for Renewables & Efficiency). 2017b. Renewable Portfolio 

Standard. Accessed March 26, 2017. http://programs.dsireusa.org/system/program/detail/479

Fu, Ran, David Feldman, Robert Margolis, Mike Woodhouse, and Kristen Ardani. 2017. U.S. 

Solar Photovoltaic System Cost Benchmark: Q1 2017. Golden, CO: National Renewable Energy 

Laboratory. Technical Report NREL/TP-6A20-68925. 

https://www.nrel.gov/docs/fy17osti/68925.pdf.

Massachusetts Distributed Generation Interconnection Working Group. 2012. Proposed Changes 

to the Uniform Standards for Interconnecting Distributed Generation. 

http://massdg.raabassociates.org/Articles/Final%20MA%20DG%20WG%20Report%209-14-

12.pdf

National Grid. 2016. Interconnection Tariff 

https://www9.nationalgridus.com/non_html/Interconnect_stds_MA.pdf

The Commonwealth of Massachusetts Department of Public Utilities. 2013. D.P.U. 11-75-E, 

Investigation by the Department of Public Utilities on its own Motion into Distributed

Generation Interconnection. http://massdg.raabassociates.org/Articles/DPU%2011-75-E-3-13-

13.pdf

The Commonwealth of Massachusetts Department of Telecommunications & Energy. 2005. 

Massachusetts Department of Telecommunications and Energy 2005 Annual Report.

http://archives.lib.state.ma.us/bitstream/handle/2452/264008/ocm46914643-

2005.pdf?sequence=1&isAllowed=y
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This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.

U.S. Energy Information Administration. 2017. Form EIA-861M. Monthly Electric Power 

Industry Report. Washington, D.C.: U.S. Energy Information Administration.

https://www.eia.gov/electricity/data/eia861m/

U.S. Federal Energy Regulatory Commission. 2013. Small Generator Interconnection 

Agreements and Procedures. 18 CFR Part 35. https://www.ferc.gov/whats-new/commmeet/2013/112113/E-1.pdf
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Appendix A. National Grid Pre-application Request
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Appendix B. DOER Monthly Interconnection 

Reporting Raw Data Fields

Company Name

City/Town

Facility ID (if any)

ZIP Code

Design Capacity (kW)

Fuel Type (Solar, Wind, etc.)

Circuit Name

Date Application Received

Date Application Deemed Complete

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Review of Screens Study Begun

Date Review of Screens Study Completed

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Supplemental Review Begun 

Date Supplemental Review Complete 

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage
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Date Standard Process Initial Review Begun 

Date Standard Process Initial Review Complete 

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Impact Study Begun

Date Impact Study Sent

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Detailed Study Begun

Date Detailed Study Sent

Total Time Lapsed (Workdays) calculated value

Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Interconnection Agreement Sent

Date ISA & Payment Received

Estimated In-Service Date

System Modification Required

Expedited/ Standard / Complex Project

Construction Timeline Commitment (Workdays)

Date Construction Begun

Date Construction Completed

Total Time Lapsed (Workdays) calculated value
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Customer Time Lapsed (Workdays) enter workdays of "clock" stoppage by Customer

Utility Time Lapsed (Workdays) enter workdays without "clock" stoppage

Date Witness Test Scheduled

Date Witness Test Completed

Authorization to Interconnect

NOTES

Date of Info Request

Private/Gov't

Net Metered? (Y/N)

Status of Project

Project count

Circuit Name Edits

City/Town Edits

Feeder/ Circuit Voltage

Device Type

Valid Circuit Name

Date Application Deemed Complete Edit

Date Impact Study Begun Edit

Date Impact Study Sent Edit

Date Interconnection Agreement Sent Edit

Substation Name

Substation Number
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Appendix C. DOER Interconnection Data Cleaning

Column Name Description Data Cleaning

Fuel Type (Solar, 

Wind, etc.)

Fuel type for project Delete all rows excluding PV, PV & Battery, Solar, and 

Solar and Battery

Design Capacity 

(kW)

Design capacity (kW) 

for application 

Select blank entries and delete corresponding rows

Date Application

Deemed Complete

Date application 

deemed complete by 

utility 

Select blank and erroneous (i.e., 1/1/1900), then delete 

corresponding rows 

Date Impact Study 

Begun

Date Impact Study 

Begun

Blank cells changed to “(blank)”

Date Detailed 

Study Begun

Date Detailed Study 

Begun

Blank cells changed to “(blank)”

System 

Modification 

Required

States if system 

modification is 

required 

Blanks changed to “no”, “N” changed to “no”, "na" 

changed to "no", "n/a" changed to "no". Removed 

applications with “tbd”, “withdrawn” and “m” 

Status of Project Project status Remove “2 - In Process” projects

Data Source: https://sites.google.com/site/massdgic/home/interconnection > Raw data for April 2018, 

posted May 21, 2018.
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Appendix D. Massachusetts Interconnection Process