[Remote] Electrical Engineer III/Subject Matter Expert

Note: The job is a remote job and is open to candidates in USA. Castillo Engineering is a fast-growing, mission-driven firm focused on renewable energy projects. They are seeking an Electrical Engineer III who will lead the electrical design of utility-scale solar and battery storage projects, ensuring all technical and regulatory requirements are met. Responsibilities • Lead and manage the electrical design of utility-scale, ground-mounted Solar PV and Battery Energy Storage Systems (BESS), including system architecture, DC/AC electrical layout, and integration with power generation, distribution, and control systems • Develop and review key deliverables: single-line diagrams (SLDs), one-line development, battery sizing analyses, inverter and transformer selection, cable ampacity calculations, grounding and bonding designs, and protective relaying schemes • Develop interconnection diagrams for standalone, grid-connected, and hybrid PV/BESS systems including medium-voltage distribution and substation interfaces • Conduct and review power system studies including load flow, short-circuit, arc flash, protection coordination, and voltage drop analyses using ETAP, SKM, or equivalent tools • Review feasibility studies, site assessments, and energy storage system sizing analyses to evaluate project viability, identify technical requirements, and recommend optimal BESS configurations — including provisions for future capacity augmentation • Serve as Engineer of Record (EOR) — stamp and seal electrical deliverables across applicable jurisdictions, with ability to obtain reciprocal PE licensure in multiple states • Manage electrical scope within EPC project structures, coordinating across engineering, procurement, and construction phases from early-stage feasibility through commercial operation date (COD) • Oversee design development, contract reviews, system interconnection requirements, and performance modeling throughout the full project lifecycle • Collaborate with EPC partners, construction teams, and internal project managers to resolve technical issues, maintain schedule, and control scope • Development of technical specifications for BESS components (battery cabinets, inverters, transformers, switchgear, metering, and control systems) • Provide engineering support for system testing, validation, and commissioning of PV and BESS systems, coordinating with stakeholders to ensure successful integration and performance validation • Serve as the technical authority and discipline lead for electrical engineering across PV and BESS projects • Develop and enforce discipline-specific design criteria, standards, and best practices for renewable energy projects • Oversee system modeling and simulation to optimize BESS performance, efficiency, and reliability — considering load profiles, grid requirements, and ancillary services • Stay current on solar PV and BESS technologies, grid integration advancements, energy management systems, and evolving regulatory requirements • Act as the client-facing technical representative for electrical scope discussions, design presentations, and project meetings • Identify and communicate project risks related to PV and BESS electrical systems, providing mitigation strategies and recommendations • Support proposals, scope development, and cost estimates for renewable energy engineering services • Participate in industry organizations and technical working groups to represent Castillo Engineering and build the firm's renewable energy presence Skills • Masters or bachelor's degree in electrical engineering from an ABET-accredited institution • Active Professional Engineer (PE) license — with willingness and ability to obtain reciprocal licensure in multiple U.S. states • Minimum 10 years of electrical engineering experience, with at least 5 years focused on utility-scale Solar PV and/or BESS projects • Demonstrated EOR experience — ability to stamp and seal electrical engineering deliverables on utility-scale renewable projects • Proven EPC project experience with a track record of managing scope across engineering, procurement, and construction phases • In-depth expertise in PV system design including battery sizing, one-line development, site layout, inverter and transformer selection, cable ampacity calculations, grounding/bonding, and protective relaying • Hands-on proficiency with power systems analysis tools: ETAP, SKM PowerTools, or equivalent • Proficiency with Solar PV modeling software: PVsyst, or equivalent • Strong knowledge of applicable codes and standards: NEC, NFPA 70E, IEEE, ANSI, and OSHA electrical regulations as applied to PV and BESS installations • Experience with medium-voltage electrical systems and grid interconnection requirements • Strong written and verbal communication skills with ability to present complex technical content to clients and non-technical stakeholders • Experience with substation design, high-voltage systems (>34.5 kV), or microgrid design preferred • Familiarity with BESS augmentation planning, state-of-charge management, and ancillary services design preferred • Proficiency in AutoCAD preferred • Prior experience in an engineering consulting or EPC firm environment preferred • A mix of field engineering, EOR, owner's engineer (OE), and EPC experience in renewable energy is highly desirable preferred Benefits • This role has an onsite or remote work arrangement • Health, dental, and vision insurance (if applicable) • Paid time off • Company holidays • Professional growth opportunities • Supportive culture committed to mentorship, innovation, and continuous improvement • Performance-based bonuses Company Overview • Castillo Engineering offers utility and residential solar engineering services. It was founded in 1998, and is headquartered in Maitland, Florida, USA, with a workforce of 51-200 employees. Its website is https://www.castillope.com. Company H1B Sponsorship • Castillo Engineering has a track record of offering H1B sponsorships, with 2 in 2026, 4 in 2025, 2 in 2024, 2 in 2023, 2 in 2022, 1 in 2020. Please note that this does not guarantee sponsorship for this specific role.