Solar Expert Witness


Shedding light on complex solar industry legal concerns


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The Solar Expert


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Welcome to SepiSolar, where we uphold the integrity of the solar industry by providing construction, civil, and patent litigation firms with case review and expert witness services. As fervent advocates for sustainable energy, we have positioned ourselves as the premier expert witness for solar-related cases. Our commitment to transparency, ethical practices, and cutting-edge knowledge has made us a trusted authority in the field.




Bodies of Law

Patent

  • Person of Ordinary Skill
    in the Art (POSITA/POSA)
  • Invalidity
  • Infringement
  • Claim Construction
  • Indefiniteness
  • Obviousness
  • Anticipation


 

Civil

  • Misrepresentation
  • Negligence
  • Contracts
  • Fraud
  • Property Damage
  • Performance
  • Wrongful Termination


 

Construction

  • Defects
  • Spearin Doctrine
  • Payment Disputes
  • Bonds & Liens
  • Delay Claims
  • Noncompliance
  • Contract Disputes


How We Contribute

  • Reports
  • Depositions
  • Trials & Hearings
  • Litigation & Arbitration
  • Opinions & Analysis
  • Rebuttals
  • Industry Standards
  • Property Inspections



Josh Weiner, CEO


Experience
CEO, SepiSolar
Feb 2009 – Present (15 years+)

SepiSolar is a solar PV and storage design and engineering company that specializes in supporting solar EPC’s, contractors, developers, and installers. SepiSolar’s design team focuses on residential, commercial, and utility-scale system design and engineering, as well as product design consulting to ensure new products meet NEC, UL ratings, and applicable codes. Our team comprises of NABCEP-certified professionals so that you know you’re getting the industry experience you need to install systems as efficiently as possible.



Director of Storage Integration, Nextracker Inc.
Jul 2015 – 2019 (4 years 6 months)

Providing technology due diligence, business development, project development, and program management to the new products team.



Director of Engineering/Engineering Consultant, NRG Energy
Feb 2013 – Feb 2015 (2 years 1 month)

Supported NRG’s transition as Director of Engineering from SunCap to Residential Solar Solutions, and eventually to NRG Home Solar through the acquisition of Roof Diagnostics Solar. Created policies and procedures for technical underwriting and scaling the Engineering department’s tools, staffing, and resources to support lease sales volumes of $10M+ per month. Post-September 2014, continue to serve as Engineering & Technology Consultant and subject matter expert for technical due diligence efforts with new technologies, products / applications, markets, and investors.





Engineering Consultant, ENGIE Storage
Jan 2009 – Jul 2013 (4 years 7 months)

Helped to secure DOE funding for R&D in 2009. Provided complete, turnkey design & engineering of all projects deployed until 2013. Also provided project management, technology consulting, business development, sales / pro-forma modeling, product development / UL certification, among many other roles to bring energy storage products from conception to commercialization.



Instructor, University of California, Berkeley
Jan 2010 – Jun 2010 (6 months)

Created and developed course curricula (including training workshops, seminars, final projects, etc.) for students of the UC Berkeley Extension program for the “Advanced PV System Design and Project Management” course. Taught classes of 10-30 students in solar PV system design, engineering, development, and project management.



Engineering Manager, Akeena Solar
May 2006 – Feb 2009 (2 years 10 months)

Designed and engineered solar installations and plans to meet current Codes and standards for residential and commercial photovoltaic installations. Duties included obtaining required permits and assisting installations and inspections with engineering support. Provided engineering support to Sales. Also assisted several municipalities to develop streamlined permitting procedures for photovoltaic permits. Presented new products and standards of workmanship to local municipalities. Assisted in the management and coordination of designs and engineering procedures with headquarters, existing remote offices, and new regional offices. Developed and implemented engineering policies, procedures, quality control, and was the sole point-of-contact for the Engineering department. Served as manager of Engineering, reporting directly to the CEO, and managed/monitored the work of 11 design engineers.






Josh Weiner, CEO


EXPERIENCE
CEO, SepiSolar
Feb 2009 – Present (15 years+)

SepiSolar is a solar PV and storage design and engineering company that specializes in supporting solar EPC’s, contractors, developers, and installers. SepiSolar’s design team focuses on residential, commercial, and utility-scale system design and engineering, as well as product design consulting to ensure new products meet NEC, UL ratings, and applicable codes. Our team comprises of NABCEP-certified professionals so that you know you’re getting the industry experience you need to install systems as efficiently as possible.



Director of Storage Integration, Nextracker Inc.
Jul 2015 – 2019 (4 years 6 months)

Providing technology due diligence, business development, project development, and program management to the new products team.

View Full Experience >



EDUCATION
University of California, Berkeley
BA, Major in Astrophysics/Astronomy;
Minors in Physics and Music
2001 – 2005

Relevant Coursework:
Electromagnetism and Optics, Quantum Mechanics, Statistical Mechanics and Thermodynamics, Stellar and Nuclear Physics, Analytic Mechanics, Special and General Relativity, High Energy Particle Physics and Astrophysics, Cosmology and Relativistic Astrophysics, Planetary Astrophysics and Atmospheric Physics, Experimental Astronomy Lab and Error Analysis, Differential Calculus, Multi-variable Calculus, linear algebra, Statistics and Probability.

View Full Education >




QUALIFICATIONS

  • BA in Astrophysics (minors in Physics & Music), UC Berkeley
  • Named as a 40 Under 40 Changemaker in 2018 by Renewable Energy World.
  • Patent awarded for Load Isolation Consumption Management Systems and Methods (US 20130285446 A1)


LICENSES & CERTIFICATIONS

  • NABCEP certification 092907-34 (2007 – present)
  • CalSEIA member (2016 – present)


SOLAR PROJECTS

  • 1,000+ (5+ MW) residential systems designed
  • 200+ (50+ MW) commercial, industrial, agricultural systems designed

View More Projects >



SKILLS

  • Project Development,
    Planning, Execution, & Operations
  • Asset Management
  • Design Development
  • Project Engineering
  • Project Management
  • Engineering Operations
    & Management
  • Sales Engineering
  • Training

View All Skills >




Frequently Asked Questions


  • Why should I trust SepiSolar’s expert witness services?
  • How does SepiSolar ensure trustworthy expert witness testimony?
Why should I trust SepiSolar’s expert witness services?

SepiSolar’s CEO, Josh Weiner, is a recognized industry leader with a degree in astrophysics and decades of solar engineering expertise. His credibility has been established through years of designing, inspecting, qualifying, and testifying on solar projects nationwide.

How does SepiSolar ensure trustworthy expert witness testimony?

Josh Weiner provides impartial, fact-based testimony grounded in real engineering principles, industry codes, and safety standards. His professional integrity ensures that law firms and courts receive accurate and unbiased evaluations.


  • What makes Josh Weiner an effective and likable expert witness?
What makes Josh Weiner an effective and likable expert witness?

Josh has a unique ability to simplify complex solar and energy storage concepts into clear, courtroom-ready explanations. Judges and juries find his testimony relatable, easy to understand, and highly professional.







Expert Witness Testimonials


We brought Josh on a little late in a large scale solar array construction arbitration and he was highly responsive and able to provide a very persuasive report by the deadline. His technical knowledge of solar array design, engineering, delay analysis and project processes were very impressive and he is able to effectively communicate complex topics to non-experts. Josh also testified at the arbitration and performed extremely well which helped us obtain stipulated dismissal of a very large portion of the opposing party’s claims. I would strongly recommend Josh as an expert witness.”

Aaron J. Graf | Attorney,
Mawicke & Goisman, S.C.

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 | Attorney,
Berliner Cohen LLP

CA Small Business Enterprise

Certification ID:
2015743

Bidder/Supplier ID:
BID0068933

NAICS Codes:
541330 – Engineering services
541340 – Drafting services
541490 – Other specialized design services
541618 – Other management consulting services
541690 – Other scientific and technical consulting services
541990 – All other professional, scientific, and technical services

D-U-N-S number:
065817064
CAGE:
8F5K7

UNSPSC Code:
811024, 81101701, 81101516, 81101604, 43232614, 81101505




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