Willdan is a professional and technical services firm serving utilities, public agencies, and commercial customers. Energy services represent roughly 85% of revenue, with the remaining 15% coming from engineering and consulting work for municipalities. On the energy side, Willdan acts as a program implementer for large electric utilities — handling customer outreach, energy audits, project design, and installation oversight to help utilities meet state-mandated energy savings targets. Key clients include Southern California Edison, ConEdison, and Duke Energy. Willdan also provides grid planning, power engineering, and data analytics to governments and, increasingly, to commercial data center developers and hyperscalers, including substation design and construction management via its 2025 acquisition of APG. The engineering and consulting segment provides outsourced civil engineering, building and safety, traffic, planning, and financial consulting to small and mid-sized municipalities that find it more cost-effective than maintaining in-house staff. Willdan's contracts are split across fixed-price, unit-based, and time-and-materials structures, with utility contracts typically running 3-5 years. Willdan pursues a "land and expand" model: upfront consulting and grid analytics work feeds into engineering contracts, which eventually feed into longer-term energy efficiency program work. Growth comes from expanding existing customer relationships and M&A to add new capabilities. Willdan also benefits from Section 179D tax deductions tied to energy-efficient government building projects, though that benefit is set to expire in mid-2026.