Principal Engineer, Solar & Energy Storage

Job Description

Job Description

Principal Engineer, Solar & Energy Storage

Renogy X | Ontario, California

Position Overview

Renogy X is seeking a hands-on senior engineer to serve as its technical lead for solar, battery energy storage, and integrated energy solutions, with a primary focus on commercial and industrial (C&I) projects.

This role requires someone who can personally develop solutions-from reviewing customer requirements and site data to sizing systems, selecting equipment, preparing preliminary electrical concepts, and producing proposal-ready technical packages.

The position initially has no direct reports. You will work closely with our engineering counterpart in China, external licensed engineers, equipment manufacturers, sales, and project management. Success will be measured by the quality, practicality, and timeliness of your technical work and decisions.

Key Responsibilities

Hands-On Solution Development

• Independently assess utility bills, interval load data, site conditions, electrical infrastructure, and customer operating requirements.
• Perform preliminary PV and battery sizing, load and backup assessments, and equipment capacity calculations.
• Develop system architectures, preliminary single-line diagrams, equipment configurations, bills of materials, and technical scopes of work.
• Define operating strategies for self-consumption, demand management, export control, and backup power.
• Prepare customer-ready technical proposals with clear assumptions, limitations, and equipment recommendations.

Equipment Selection & System Integration

• Select and evaluate batteries, inverters, PCS, transformers, switchgear, protection equipment, and EMS platforms.
• Verify compatibility across equipment, electrical interfaces, communications, and control functions.
• Develop practical solutions for grid-connected systems, off-grid applications, microgrids, and EV charging integration.
• Obtain and validate technical information directly with manufacturers rather than relying solely on marketing materials.

Engineering Review & Project Economics

• Review detailed drawings, calculations, equipment specifications, and installation scopes.
• Independently evaluate EPC quotations and identify missing scope, unsuitable equipment, and unreasonable technical assumptions.
• Develop alternative configurations to improve project cost, constructability, reliability, and performance.
• Coordinate detailed design with our engineering counterpart in China and external engineering partners.
• Arrange licensed engineering review and stamping where required.

Codes, Permitting & Interconnection

• Apply relevant electrical, building, fire safety, and utility requirements during solution development.
• Identify permitting, equipment certification, siting, and interconnection constraints before proposals are finalized.
• Prepare technical responses to comments from utilities, permitting authorities, and fire departments.
• Track relevant regulatory and program changes and explain their practical impact on project design and equipment selection.

Customer & Field Support

• Lead technical discussions with customers and explain design choices and trade-offs clearly.
• Participate in site assessments and resolve technical questions during project development and installation.
• Support commissioning, system troubleshooting, and root-cause analysis of performance issues.
• Convert lessons learned into reusable designs, checklists, and technical guidance.

Required Qualifications

• 8+ years of relevant experience in electrical engineering, solar, energy storage, or EPC project delivery, including substantial hands-on C&I experience.
• Demonstrated ability to independently develop solar and storage solutions, supported by examples of personally completed designs, calculations, or technical deliverables.
• Strong knowledge of California electrical and fire safety requirements, permitting, and utility interconnection.
• Practical experience with commercial electrical distribution, transformers, switchgear, inverters, PCS, batteries, and controls.
• Ability to produce and review preliminary single-line diagrams, system sizing calculations, equipment schedules, and bills of materials.
• Experience supporting projects through design, installation, and commissioning.
• Proficiency with relevant electrical drafting, solar modeling, and engineering calculation tools.
• Ability to work independently, make sound technical decisions, and coordinate effectively with overseas engineering resources.
• Bachelor's degree in electrical engineering or a related discipline, or equivalent substantial practical experience.

Preferred Qualifications

• California Professional Engineer (PE) license.
• Experience with microgrids, generator integration, medium-voltage systems, or critical power infrastructure.
• Experience with both residential and C&I solar and storage applications.
• Experience developing standardized solutions and engineering workflows for an EPC business.