Energy Expert Witness

Solar Energy Expert Witness Services

Meet Our Solar Energy Expert Witness

Joshua Weiner, CEO of SepiSolar, provides expert witness services and case review for construction law and civil litigation firms representing plaintiffs and defense. Weiner can fulfill your expert witness search and support discovery, analysis, and fact-finding for projects that result of a financial loss, technical failure, or contractual claim. Schedule your free consultation today.


Professional Expertise

As a solar pv expert witness, Weiner brings knowledge of law, policy, technology, contracts, finance, permits and entitlements, project development and construction, data acquisition and analysis that commonly apply to renewable energy and distributed energy projects.

Specific areas of expertise, listed below, include energy technologies, markets, policy, finance, project development, planning and execution, project management, and codes and standards.

Weiner is adept at unpacking complex topics into simple language that all parties can understand.

Since 2007, Weiner is a certified member of the North American Board of Certified Energy Practitioners (NABCEP) in good standing. Weiner has also taught advanced solar system design and project management at UC Berkeley.

Josh Weiner, Solar Energy Expert Witness

Josh Weiner, Solar Expert Witness

Areas of Expertise

Energy Technologies

  • Solar
  • Batteries & Energy Storage
  • Microgrids


  • Utility-Scale
  • Commercial & Industrial
  • Agricultural
  • Residential


  • Tariff Rates
  • Net Energy Metering (NEM)
  • Interconnection Agreements


  • Incentive Programs & Structures
  • Financing Programs & Structures

Project Development

  • Performance Modeling & Simulation
  • Financial Modeling
  • Contract Structures
  • Ownership Models

Project Planning & Execution

  • Construction Management
  • Sales Proposals, Pro Formas & Cash Flow Statements
  • Technical Design
  • Project Engineering
  • Owner’s Engineering
  • Independent Engineering
  • System Design & Architecture
  • Control Strategies & Microgrid Operations

Project Management

  • Technology Due Diligence
  • Product & Vendor Selection
  • Product Warranties, Guarantees & Liabilities
  • Operations & Maintenance
  • Data Acquisition & Monitoring

Codes & Standards

  • Health & Safety
  • National Electrical Code
  • UL
  • Municipal Permits
  • Industry Codes & Standards
  • Solar Rights Act

Expert Witness experience

In addition to consulting for NEXTracker, NRG Home Solar, and Green Charge Networks (now, ENGIE Storage), the below is a summary of Weiner’s expert witness experience.

  • Reviewed disputes and claims between project owners and Engineering, Procurement, and Construction (EPC) design-build companies involving contract, project, and construction documents as well as monitoring and performance data
  • Performed discovery and analysis (financial, technical, regulatory) to identify complex issues, then translating and articulating them in relatively simple terms
  • Performed project site visits and inspections to verify and analyze system health, performance, construction defects, regulatory compliance, contractual compliance, and utility interconnection compliance

Professional Experience

Weiner’s professional experience includes engineering and design for

  • 1,000+  residential systems (5+ MW overall)
  • 200+ commercial, industrial, agricultural systems (50+ MW overall)
  • 12+ utility-scale systems (70+ MW overall)
  • 15+ utility-interactive energy storage systems (8+ MWh overall)


BA in Astrophysics (minors in Physics & Music), UC Berkeley

Awards and Affiliation

  • NABCEP certification (2007 – present)
  • CalSEIA member (2016 – present)
  • Patent awarded for Load Isolation Consumption Management Systems and Methods (US 20130285446 A1)


To get in touch with our Solar Energy Expert Witness:

To contact our Solar Energy Expert Witness:


CA Small Business Enterprise

Certification ID:

Bidder/Supplier ID:

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:

811024, 81101701, 81101516, 81101604, 43232614, 81101505

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