Engineering you can build on.
Testimony you can stand on.

Specializing in renewable energy projects, SepiSolar possesses a vast array of expertise and years of industry experience—from initial conception through to project completion. Our proficiency not only shines in technical engagement but also in our deep understanding of the intricate federal and state regulatory landscapes. With SepiSolar, you gain access to a seasoned partner whose focus is to ensure that your renewable energy projects are brilliantly realized and impeccably executed.

25+

Years in Solar Engineering

23k+

Projects Designed and Stamped

01)

For EPCs, Developers & Installers

SOLAR & STORAGE ENGINEERING

Design and engineering services for commercial, industrial, utility-scale, energy storage, and microgrid projects. All engineered to NEC, UL, and local codes.

02)

For Law Firms & Legal Professionals

SOLAR EXPERT WITNESS

Case review, discovery support, and courtroom testimony for construction, civil and patent litigation. Impartial opinions grounded in real-world engineering practice.

350

Expert Witness Consultations

Proven in the field. Trusted in court.

350

Expert Witness Consultations

Joshua Weiner has spent two decades solving solar's hardest technical problems, first as an engineer and, since 2009, as founder and CEO of SepiSolar. He's a UC Berkeley-trained astrophysicist, NABCEP-certified since 2007, and has taught advanced PV design at Berkeley while leading his team through more than 23,500 projects nationwide. That depth of experience is exactly why law firms call on him and the SepiSolar team as a solar expert witness in performance, failure, and construction defect cases.

Review Joshua's CV

Trusted by engineers and attorneys.

Using SepiSolar for designing and engineering Swell Energy’s solar-plus-storage systems was a no-brainer. Storage is complicated, so we wanted to work with a team of U.S.-based quality engineers who could speak ‘fluent storage’ and get out accurate plan sets quickly and with minimal AHJ revisions.

Andrew Meyer – Swell Energy

Josh brings to the table, not only his vast knowledge of the solar industry, but a solid and thorough comprehension of issues. He was exceptionally prepared and invested in our case.

Kim Descamps – Berliner Cohen LLP

Our Mission

To help others unlock the value of renewable energy infrastructure, and to defend it when that value is in question.

These may seem like just a few words, but they're truly meaningful for all of us here at SepiSolar. We genuinely care about our work, each other, our clients, and the community, whether we're designing a system or standing behind one in a courtroom. The community we're building includes everyone: engineers, developers, attorneys, and anyone who depends on solar and storage performing as promised. How people create, use, and rely on energy guides our solutions, both in the field and in the cases where that reliability is being tested.

Recent Case Study

Sonic Manufacturing Technologies — Sonic Manufacturing Technologies decided to go solar, but was required by the City of Fremont to have a mechanical screen shielding the roof’s HVAC units from view from the surrounding...

Want to Save on Your Title 24 Projects? Consider This One Thing.

This post was written by Josh Weiner, Solar Expert Witness & Solar Project Development Expert. Mr. Weiner has been at the forefront of the solar industry for over...