Permitting and siting of wind and solar in Massachusetts: processes, timelines, and outcomes

Permitting reform, shaped by local and state governance, could eliminate unnecessary administrative burdens that slow the development of new electricity generation. However, the permitting process or duration is not well known, especially for locally-permitted projects, which are the standard in the U.S. Northeast and the most common permitting type in the United States. Here, we create an original data set of locally-permitted wind and solar energy projects in Massachusetts to document those timelines. We find that, on average, the permitting duration lasted 250 days, and this duration has increased over time. Permitted and lower capacity projects were associated with shorter permitting duration while canceled and larger capacity projects are associated with longer permitting duration. The results represent the first attempt to calculate permitting speed for locally-permitted wind and solar energy projects at a time when several states are reforming permitting policies, including Massachusetts. This study, therefore, contributes to both the academic and policy debates about how to balance fast deployment with fair practices that weigh the concerns of local communities.

The speed and scale of developing new energy supply is heavily dependent on state and local leadership (Katz and Baillargeon, 2025). One key barrier that stakeholders grapple with is often uncertain permitting processes, timelines, and outcomes (Hess and Ruhl, 2025). They are cited by developers as a leading cause of delays and cancellations (Nilson et al., 2024). Permitting refers to the rules and procedures needed to obtain permission to site and build energy facilities, often influencing outcomes related to project design and location (O'Shaughnessy et al., 2025). Permitting authority for solar and onshore wind is primarily under state or local jurisdiction in the U.S. (Enterline et al., 2024; Mai et al., 2025). Massachusetts' permitting framework, the focus of this study, offers an important window into implementation that other states may learn from. Here, we conduct a first-of-its-kind permitting timelines analysis for locally-permitted wind and solar energy projects in Massachusetts, investigating how these timelines differ among key sample cohorts.

Land use authority is a state function delegated to counties and municipalities via zoning and enabling acts under home-rule or Dillon's Rule frameworks.1 This structure reflects Constitutional principles wherein powers not granted to the federal government are reserved to the states under the Tenth Amendment and retained or delegated. The entity that holds the principal decision-making power over the permitting processes is the primary authority having jurisdiction (AHJ). The structure of state and local jurisdictions varies both across states and within states (Enterline et al., 2024). Some degree of local-based jurisdiction over permitting is most common, often shared with state-based jurisdiction, where both levels of government hold some authority or the AHJ is contingent on project characteristics, such as capacity (Enterline et al., 2024). Therefore, in many cases, variation in permitting processes and rules do not occur just across states but across counties and municipalities.

The AHJ in Massachusetts is contingent on project size (i.e., installed capacity exceeding 100 MW (or 25 MW after March 2026) falls under state jurisdiction); to date, no project has been large enough to preempt local authority. Localities exist within the state's legal frameworks; however, there is limited state guidance and oversight when the AHJ is local. The primary state laws applicable to local processes relates to public hearing transparency and meeting structure (Mass. Gen. Laws ch. 40A, §, 9), or authority limitations due to court rulings (Heuer et al., 2025). As such, processes and rules vary widely across the 351 Massachusetts cities and towns.

However, Massachusetts is among a wave of states rethinking permitting as pressure mounts to meet clean energy2 targets, improve public participation, and respond to concerns over rising electricity costs. Massachusetts enacted Chapter 239 of the Acts of 2024 in November 2024, which, among other changes, directed several permitting changes (2024 Mass. Acts ch., 239). The new law, among other provisions, directs agencies to establish a standard, consolidate local permitting processes, establish binding timelines for local permitting decisions, elevate community engagement efforts, and provide greater technical support to local governments (Gerson, 2024). Notably, Massachusetts maintains town-based AHJ for most energy projects, despite growing anecdotal evidence that local AHJ slows permitting speeds due to fewer resources to complete project reviews and more opportunities for local project vetoes (Hess et al., 2025; Nilson et al., 2024). This anecdotal evidence would benefit from systematic analysis of permitting timelines in the Commonwealth; a gap this study seeks to fill.

This research adds value in several ways. The impacts of the new Massachusetts permitting law will remain unclear until promulgation but understanding the current state of permitting in the Commonwealth provides an essential baseline understanding to compare and evaluate future timelines. Furthermore, the Commonwealth's experience can inform other states' permitting reform. Finally, this study represents the first systematic dataset of local-level timelines and outcomes, which provides an opportunity for comparisons between local- vs. state-based AHJ in this and other states.

Data

The primary aim of the research is to establish the time between permit application and application decision for projects in our sample. We developed a schema for categorizing key stages in the permitting process. Our focus was projects that entered the permitting process in or after 2018, though, we also include any earlier projects' data (including projects with a submission year as early as 2009) when they were present in any AHJ we were already collecting data from. Data was difficult to collect, so when encountered, we gathered data, even outside of the target period.

To create the project sample, we used U.S. Energy Information Administration (EIA)'s Preliminary Monthly Electric Generator Inventory (data derived from Form EIA-860M) (U.S. EIA, 2025) and the U.S. Large Scale Photovoltaic Database (USPVDB) (Fujita et al., 2023). However, these sources do not include all projects that entered a permitting process. There is no single database, including EIA, that tracks all projects, across AHJs, that sought permitting. This remains an ongoing challenge for energy researchers in establishing what the true population of projects is in a given state or locality.

The sampling strategy was purposive. We sought diversity across the following dimensions: project status (e.g., permitted and canceled), town size, geography, county representation, and project density. We searched for evidence of permitting timeline and process in 41 towns, representing approximately 21% of Massachusetts towns that were identified as having at least one project in EIA data.

Data availability was a major challenge because Massachusetts does not have a single permitting portal (this has since changed and will be implemented in 2026). As such, most locations have no database or public-facing source of information related to permitting for wind and solar. We were only able to collect data from 25 towns. Each search was exhaustive and ended when no additional data could be found.

The data collection effort sought the date of discrete steps in the permitting process. Steps included application submission to AHJ (the “start date”), public hearing dates, and special permit decisions (“end date”) used to calculate permitting duration. While our full sample includes 42 energy projects in 25 Massachusetts towns for which one or more date points were gathered, we were only able to collect both application submission and application decision dates for 26 of the 42 projects, in 17 towns. Thus, we can only calculate permitting timelines for this subset.

Data was collected from publicly available documents, including meeting minutes, site plans, permit applications, and media coverage. Often, permitting timelines and outcomes are pieced together across several resources. For instance, we might find a permit application on a town website that includes the date of submission but need a transcript of a town meeting to find the date the project was permitted (or denied). Collected documents were saved and organized by type. When public information was not available, researchers contacted local officials directly via phone and email. Direct contact frequently resulted in no response, or alternatively, the data we sought could not be located, due to, as we witnessed, non-standard processes for data retention in these small, local government settings.

Analytical approach

We conducted descriptive and statistical tests on the subset of data for which we have permit timelines to examine the relationship between permitting duration and three explanatory variables: decision year, permit status, and installed capacity. We organize decision year into three categories (2009–2014, 2015–2019, and 2020–2025), creating approximately equal length year categories. We organize permit status into three categories, permitted, lawsuit, and canceled. “Permitted” includes any projects that received a permit approval, including operating, under construction, or projects awaiting construction. “Lawsuit” includes projects that are undergoing active lawsuits. Most “lawsuit” projects are in court to challenge the permitting decision (approved), and the challenges are oriented around land use concerns, such as environmental and viewshed impacts. While lawsuits are not a part of the formal permitting process, court decisions have informed permitting law and outcomes, such as terminating or canceling the project, in Massachusetts (Heuer et al., 2025; Merzbach, 2025b; Saint-Val, 2025). Finally, “canceled” projects represent projects that have been denied, withdrawn, or terminated. Installed capacity is similarly organized into three groups based on project installed capacity (MW): ≤ 2, >2– <5, and ≥5. These groupings balance sample size, while respecting Massachusetts median wind and solar project size of 2 MW (U.S. EIA, 2025).

Permitting duration was non-normally distributed, and sample sizes were small within factor levels. As a result, we employed the non-parametric Kruskal–Wallis test [referred to below as “H(2)”]. When Kruskal–Wallis tests were significant, we conducted post-hoc pairwise comparisons using pairwise Wilcoxon rank-sum tests with Benjamini–Hochberg correction applied within each factor (referred to below as “FDR”). All statistical modeling was completed in R Statistical Software (v4.4.1, Vienna; R Core Team, 2024)/RStudio (v.4.2, Posit Team, 2024).

The subsample, described in Table 1, includes 26 renewable energy projects that entered the permitting process between 2009 and 2023 with the majority (77%) entering after 2017. Most projects are solar or solar+storage (88%). Projects are in 17 towns (across six counties). Project capacities were mostly ≤ 2 MW (46%), but > 2– <5 (27%) and ≥5 (27%) were well-represented.

In total, we utilized 131 documents to derive variables. On average, five different documents were used per project. The most common documents were letters, meeting minutes, and site plans (Supplementary Figure S1). Most letters were from developers, responding to comments or asking for extensions, or project abutters, providing feedback. All reviewed abutters' letters called either for permit denial or raised concerns about the project.3 Concerns included contamination of drinking water, disturbing groundwater runoff, and environmental impacts of deforestation.

We find a mean permitting duration of 250 days and a median of 173 days, but this varies among several characteristics. Figure 1 reports permitting duration by decision year categories, showing it increases over time in the sample. We find the same trend for submission year categories (not shown). Median ranks of permitting duration differed significantly among the three decision year groups [H(2) = 11.2, p = 0.00377] with a large effect size [η 2 = 0.24, 95% CI (0.05, 0.42)]. Projects that entered the process between 2020 and 2025 were significantly longer in duration than those from 2009 to 2014 (FPR p = 0.002). Other pairwise comparisons were not significant. The most recent decision year category contains the greatest variation in permit status; yet, when restricting the sample to permitted projects only, projects from 2020 to 2025 remain significantly longer in duration compared to 2009–2024 (FPR p = 0.048).

We also assess the permitting duration by permit status (Figure 2). Permitted projects have the shortest permitting duration while canceled projects or those under lawsuit have longer timelines. A Levene's test found heterogeneity of variance; therefore, these results are not suitable for a Kruskal-Wallis testing statistical significance.

Finally, we compare permitting duration by MW capacity groups (Figure 3). The group's duration does not differ significantly [H(2) = 3.46, p = 0.177]. Further, delineating capacity groups by technology type resulted in too-small in-group sample sizes, but these results are shown in Supplementary Figure S2.

This first-of-a-kind-study systematically gathered data on permitting timelines and outcomes for 26 projects in Massachusetts permitted at the local level. Our data are not only relevant to Massachusetts but inform ongoing policy debates occurring across at least 47 state governments, grappling with permitting reform (Breckel and Falkenburg, 2025). Such debates are operating against the backdrop of limited empirical data. For Massachusetts, these data provide a baseline to understand the current state of permitting ahead of reforms that will begin in 2026.

The key finding in our sample is that permitting duration averaged 250 days, with a median of 173. The new Massachusetts legislation requires a decision within a year of project application, well outside our averages. In fact, most projects in our sample (81%) fall under the threshold.

Though, more recent projects taking longer might be a harbinger of ever-growing future delays. There is some evidence for this. For example, Massachusetts is a densely populated state with several competing priorities for land-use, including housing and agriculture. The sites that already host energy projects might be considered low hanging fruit locations and, therefore, what remains might be less ideal. Longer durations in more recent years could be because recent proposals are in less desirable places, such as in forests, closer to abutters, or on agriculture land (Crawford et al., 2022; Richardson et al., 2022; Wear et al., 2025), any of which may complicate permitting. Concerns raised in Massachusetts (Manning, 2023), including for specific projects in our dataset, support this theory. Instead, this trend could be the result of a rising regional or national conflict around wind and solar projects, suggested by other research (Stokes et al., 2023; Nilson et al., 2024). Whichever is the case, future research could assess whether permitting durations are increasing over time, and in other states. Identifying such trends would have important implications for the design of ongoing state permitting reform efforts in Massachusetts and beyond.

Our results also highlight the role that local conflict may play in the permitting process. In our sample, 10% of projects are under lawsuit over environmental or health concerns. We also found evidence in news coverage and public comments of opposition for several canceled projects, which were also associated with longer timelines (Harrelson, 2025; Merzbach, 2025a,b). Considering the influence of opposition is particularly important for local-based AHJs, where a small fraction of opposition can heavily drive outcomes (Firestone et al., 2018; Siting Solutions Project, 2025). While our study does not attempt to establish causation for canceled projects, the results suggest opposition may be a factor and future research is needed to understand the relationships between opposition, timelines, and outcomes.

An additional insight gained in this process is that gathering permitting data at the local level is challenging. Many local governments do not make permitting information publicly available or even retain such information on file. For example, one local official told us they destroy records on canceled projects due to limited resources. Identifying an application submission date, or the beginning of the permitting duration, was particularly challenging. While decision dates are often captured in meeting minutes, towns often do not have a formal practice for preserving the application submission date or date of approval, in a systematic way. In several cases, such records never existed or were no longer available. Notably, the lack of data availability is often less of a concern for state-based AHJ where states often maintain permitting portals with all records publicly available, such as in California (California Energy Commission, n.d.) or even in Massachusetts for large energy projects, like power plants and natural gas storage tanks (Energy Facilities Siting Board, n.d.). Another major challenge is there is no reliable way to identify the true population of projects that entered a permitting process, regardless of outcome. While we did our best to achieve a representative sample of the projects found in Massachusetts, the lack of accessible data in many towns may introduce selection bias in the data, potentially skewing our results toward projects with greater controversy or in towns with more accessible public information. Additionally, due to the complexity of the permitting process, we focused on the key permitting dates of application submission and decision. As a result, we cannot speak to what aspects of the permitting process that happen between these steps, which may alter the process duration. These data limitations present a challenge not only for this study, but for the research and policy community writ-large in developing empirically driven policy insights about permitting reform.

Accordingly, public data transparency requirements related to recorded public decisions on energy projects would improve the standardization of information related to energy deployment and provide a foundation for tracking and understanding the permitting steps and duration. However, we recognize that local governments are often under-resourced making such a requirement onerous, if not impossible, to implement without funding and other types of capacity support. In the absence of such information, it will remain very challenging to evaluate the effects of current and future policy on wind and solar energy deployment at the local level. In Massachusetts, Chapter 239 of the Acts of 2024 mandates the creation of a clean energy dashboard for all clean energy projects, regardless of the AHJ (2024 Mass. Acts ch., 239). Such dashboards may address these data transparency concerns; however, it remains unclear the level of burden this new requirement will place on local governments and how Massachusetts will enforce the towns' use of the portal.