Willdan Group

Willdan Group, Inc. is an American publicly traded professional-services company that provides engineering, energy, infrastructure, sustainability, and technical consulting services. Its customers include public agencies at municipal, state, and other government levels; investor-owned and municipal utilities; and commercial and industrial organizations. The company is headquartered in Anaheim, California, and operates offices in more than a dozen U.S. states, with historically important activity in California and New York. Willdan was established in Southern California in 1964 by William Stookey and Dan Heil. Its original business model was distinctive for the period: instead of serving only private developers or large industrial clients, the company supplied outsourced engineering support directly to municipalities, particularly communities experiencing rapid urbanization. That public-sector orientation remained an important part of Willdan's identity as its services expanded. Over time, the company moved beyond conventional municipal engineering into fields shaped by changing energy systems, environmental requirements, and the technical needs of modern cities. The company's later scope has included energy-efficiency program administration, energy engineering, cogeneration, Energy Savings Performance Contracts, renewable-energy analysis, green-building consulting, Community Choice Aggregation, smart-city planning, microgrid consulting, distributed-generation strategy, and software-supported analysis of electric networks. These capabilities allow Willdan to work across the planning, design, implementation, and evaluation stages of infrastructure and energy projects rather than limiting its role to a single engineering discipline. Willdan became a public company in 2006 through an initial public offering on NASDAQ under the symbol WLDN. Its subsequent growth relied substantially on acquisitions. The 2008 purchase of Intergy Corporation established a larger energy-efficiency utility-program platform. Acquisitions in 2015 added Energy Service Company and Energy Savings Performance Contract capabilities, while the purchase of Genesys Engineering in 2016 expanded power-engineering services. Integral Analytics, acquired in 2017, brought data analytics and software relevant to distributed generation, renewable energy, electric vehicles, storage, and smart-grid management. The company continued building an energy and sustainability portfolio through the 2018 acquisitions of Newcomb Anderson McCormick and Lime Energy. In 2019 it acquired The Weidt Group, Onsite Energy Corporation, and Energy and Environmental Economics, also known as E3. Those transactions broadened Willdan's reach into new-construction energy engineering, industrial energy efficiency, utility strategy, renewable-energy and green-building consulting, and sophisticated quantitative analysis of energy systems. In March 2025, Willdan acquired Alternative Power Generation, an electrical engineering and construction-management firm whose capabilities include data-center substation design, microgrids, electric-vehicle charging, renewable-energy projects, and commercial-sector construction management. Willdan's positioning is therefore centered on applied technical expertise for institutions managing complex infrastructure and energy transitions. Rather than being a consumer-facing product brand, it is a business-to-business and business-to-government services group. Its work typically combines engineering judgment, program management, analytics, regulatory and policy knowledge, and implementation support. The company's public-sector heritage remains visible in its municipal and utility relationships, while its acquisitions have increased its exposure to commercial energy users, data centers, electrification, distributed energy resources, and modern power-system planning.

Willdan Group was founded in 1964 in Southern California by William Stookey and Dan Heil. The founders developed a model based on providing outsourced engineering services to municipalities. This approach was particularly relevant to newly urbanizing communities that needed professional planning and infrastructure support but did not necessarily maintain large internal engineering departments. From its beginning, Willdan therefore developed around public-sector needs rather than around a traditional consumer product or a narrowly focused industrial market. During the following decades, the company expanded as the responsibilities of municipalities and utilities became more technically demanding. Engineering work increasingly intersected with energy conservation, environmental regulation, renewable generation, changing electricity markets, and the modernization of local infrastructure. Willdan developed or acquired capabilities in energy efficiency, energy engineering, cogeneration, Energy Savings Performance Contracts, Community Choice Aggregation, smart-city planning, microgrids, distributed generation, and software-supported energy analysis. A major corporate turning point came in 2006, when Willdan completed its initial public offering and began trading on NASDAQ under the symbol WLDN. Public-market access supported a broader acquisition strategy. In 2008, the company acquired Intergy Corporation and subsequently operated that business as Willdan Energy Solutions, strengthening its ability to manage utility energy-efficiency programs. In 2015, Willdan acquired 360 Energy Engineers and Abacus Resource Management. These transactions expanded its Energy Service Company capabilities and its ability to deliver Energy Savings Performance Contracts. The 2016 acquisition of Genesys Engineering, P.C., based in New York City, added power-engineering expertise. Willdan presented this capability as important to the evolution of American electricity systems toward distributed generation, microgrids, and more complex network architectures. In July 2017, Willdan acquired Integral Analytics, a big-data analytics company. Integral Analytics supplied software and analytical tools for investor-owned utilities and smart-city managers dealing with distributed solar generation, electric vehicles, renewable energy, energy storage, and other changes affecting the electric grid. The transaction extended Willdan's business beyond conventional consulting and engineering into data-driven decision support. The company added further energy and sustainability expertise in April 2018 by acquiring Newcomb Anderson McCormick. That firm had longstanding relationships with higher-education systems and public agencies, including organizations associated with the University of California, the California State University system, the California Community Colleges, and Bay Area public agencies and utilities. In November 2018, Willdan acquired Lime Energy, increasing its scale in energy-efficiency program delivery. Lime Energy had worked with a substantial number of large electric and municipal utilities in the United States. Willdan's 2019 expansion included the acquisition of The Weidt Group in March, adding new-construction energy engineering and a stronger Upper Midwest presence. In July, the company announced an expanded $200 million credit facility intended in part to support future acquisitions, and it also announced the acquisition of Onsite Energy Corporation. Onsite added industrial-sector customers and related energy-efficiency capabilities. In October 2019, Willdan announced the acquisition of Energy and Environmental Economics, Inc., commonly known as E3. Headquartered in San Francisco with offices in Boston and New York, E3 was known for data-driven energy analysis and strategy consulting, including work involving utilities, renewable energy, and environmental objectives. In March 2025, Willdan acquired Alternative Power Generation through a stock purchase. APG brought electrical engineering and construction-management experience in data-center substations, microgrids, electric-vehicle charging, renewable-energy projects, and other commercial applications. The transaction reflected Willdan's continuing effort to align its service portfolio with electrification, distributed energy, high-load commercial facilities, and the modernization of power infrastructure. Across its history, Willdan has evolved from a Southern California municipal-engineering provider into a diversified U.S. technical-services group. Its present business combines public-sector engineering roots with utility program management, power engineering, energy analytics, sustainability consulting, and commercial infrastructure services.

• 2025

  Alternative Power Generation acquisition

  [1]Willdan Groupen.wikipedia.org

  Willdan acquired Alternative Power Generation in a stock transaction, adding commercial electrical engineering and construction-management capabilities.

• 2019

  Expansion through The Weidt Group, Onsite Energy, and E3

  [1]Willdan Groupen.wikipedia.org

  Willdan acquired The Weidt Group, announced the acquisition of Onsite Energy Corporation, and announced the acquisition of Energy and Environmental Economics, expanding new-construction engineering, industrial energy services, and energy strategy consulting.

• 2018

  Newcomb Anderson McCormick and Lime Energy acquisitions

  [1]Willdan Groupen.wikipedia.org

  Willdan acquired Newcomb Anderson McCormick in April and Lime Energy in November, strengthening sustainability consulting and utility energy-efficiency program delivery.

• 2017

  Integral Analytics acquisition

  [1]Willdan Groupen.wikipedia.org

  Willdan acquired Integral Analytics, adding software and analytics for utilities and smart-city managers addressing distributed generation, electric vehicles, renewable energy, and storage.

• 2016

  Genesys Engineering acquisition

  [1]Willdan Groupen.wikipedia.org

  The acquisition of New York City-based Genesys Engineering added power-engineering services and supported work related to distributed generation and microgrids.

• 2015

  Energy-services acquisitions

  [1]Willdan Groupen.wikipedia.org

  Willdan acquired 360 Energy Engineers and Abacus Resource Management, broadening its Energy Service Company and Energy Savings Performance Contract capabilities.

• 2008

  Intergy Corporation acquisition

  [1]Willdan Groupen.wikipedia.org

  The acquisition of Intergy Corporation expanded Willdan's utility energy-efficiency program-management activities; the business was later known as Willdan Energy Solutions.

• 2006

  Initial public offering

  [1]Willdan Groupen.wikipedia.org

  Willdan completed its initial public offering and began trading on NASDAQ under the symbol WLDN.

• 1964

  Company founded in Southern California

  [1]Willdan Groupen.wikipedia.org

  William Stookey and Dan Heil established Willdan around an outsourced-engineering model serving municipalities, especially rapidly urbanizing communities.

A technical and consulting platform focused on public agencies, utilities, and commercial and industrial customers facing infrastructure modernization, energy-efficiency, electrification, sustainability, and grid-transformation requirements.

• Engineering consulting · 1964

  Municipal and public-sector engineering

  Willdan's original and continuing service area is outsourced engineering and technical consulting for municipalities and other public agencies. The work supports communities that need planning, infrastructure, technical assessment, and project-delivery expertise. This public-sector foundation distinguishes the company from engineering brands focused exclusively on private development or industrial design.

• Energy services · 2008

  Energy-efficiency program services

  The company designs, administers, and supports energy-efficiency programs for utilities and public-sector customers. Services can include program planning, customer and market engagement, implementation support, measurement, and technical management. The capability was strengthened through the Intergy and Lime Energy acquisitions.

• Energy engineering · 2015

  Energy engineering and performance contracting

  Willdan provides energy engineering and Energy Savings Performance Contract services, helping customers identify, design, and implement projects intended to reduce energy consumption or improve facility performance. The portfolio includes Energy Service Company capabilities associated with the 360 Energy Engineers and Abacus Resource Management acquisitions.

• Power systems · 2016

  Power engineering and microgrid consulting

  Power-engineering services address electrical networks, distributed generation, microgrids, renewable projects, and related infrastructure. The Genesys Engineering acquisition expanded this capability, while later acquisitions added experience relevant to electrification, charging infrastructure, and commercial power facilities.

• Energy analytics · 2017

  Energy analytics and strategy

  Through capabilities associated with Integral Analytics and E3, Willdan supports utilities and other energy-sector organizations with analytical software, quantitative modeling, and strategic advice. Applications include distributed-energy resources, electric vehicles, renewable generation, storage, grid transformation, and long-term energy planning.

• Sustainability consulting · 2018

  Sustainability and green-building consulting

  Willdan advises public agencies, institutions, utilities, and other customers on energy efficiency, renewable energy, green buildings, and sustainability programs. The Newcomb Anderson McCormick acquisition added established relationships in higher education and with public agencies and utilities.

• Electrical engineering and construction management · 2025

  Commercial electrical infrastructure services

  The Alternative Power Generation acquisition added capabilities in data-center substation design, electrical engineering, construction management, microgrids, electric-vehicle charging stations, and renewable-energy projects for commercial customers.

• 2025

  Acquisition of Alternative Power GenerationM&A

  Background

  Demand was increasing for commercial power infrastructure associated with data centers, electrification, microgrids, renewable energy, and electric-vehicle charging.

  Action taken

  Willdan acquired Alternative Power Generation through a stock purchase.

  Aftermath

  The transaction added electrical engineering and construction-management expertise for commercial-sector projects, including data-center substations and renewable-energy installations.

  Source

• 2019

  Expanded acquisition capacityStrategy

  Background

  Willdan was pursuing additional growth in energy efficiency, engineering, and strategic energy consulting.

  Action taken

  The company announced a $200 million expanded credit facility and continued its acquisition program with Onsite Energy and E3.

  Aftermath

  The financing and acquisitions broadened the company's industrial, commercial, utility, and energy-strategy offerings.

  Expanded credit facility. $200 million (2019)

  Source

• 2017

  Acquisition-led expansion into grid analyticsM&A

  Background

  Utilities and cities were facing increasing complexity from distributed generation, solar power, electric vehicles, renewable energy, and storage.

  Action taken

  Willdan acquired Integral Analytics and incorporated its software and analytical capabilities into the broader energy-services portfolio.

  Aftermath

  The transaction gave Willdan additional tools for grid transformation, distributed-energy analysis, and smart-city decision support.

  Source

• 2006

  Public-market listing to support expansionStrategy

  Background

  Willdan had developed from a municipal engineering provider into a broader technical-services company and sought public-market access.

  Action taken

  The company completed an initial public offering and listed on NASDAQ under WLDN.

  Aftermath

  The listing preceded a multi-year acquisition program that expanded Willdan's energy, power, analytics, and sustainability capabilities.

  Source

1. 1Willdan Groupen.wikipedia.org
2. 2Willdan Group official websitewilldan.com