As a Principal BESS Engineer, you will lead technical and commercial advisory services for utility-scale battery energy storage systems across development, procurement, contracting, delivery and operation. The role is particularly focused on Owner's Engineer and procurement engagements, where clients need clear advice on how a BESS should be sized, specified, evaluated and contracted to achieve its intended duty over its operating life. You will bring the technical depth to understand the system and the commercial judgement to translate that understanding into bankable requirements, meaningful bid comparisons and practical risk allocation.You will work with clients to define the duty profile and performance basis for a project, develop Principal's requirements and technical schedules, assess OEM and integrator proposals, support tender evaluations and negotiate key performance and warranty provisions. This includes net power and usable energy, state-of-charge operating windows, round-trip efficiency, auxiliary consumption, availability, degradation, cycling and throughput, augmentation, response performance, reactive-power capability, environmental derating, warranties, acceptance tests and long-term service obligations. You will also support detailed design reviews, factory and site testing, commissioning and performance verification.The common thread is being able to connect technology, contracts and lifecycle value. You will identify where apparently attractive offers rely on different assumptions, exclusions or operating limits, explain the consequences clearly, and help clients make decisions that remain robust after contract award. The role will suit a BESS specialist who is equally comfortable interrogating a technical proposal, leading a commercial discussion and coordinating the wider electrical, civil, fire, grid and operational interfaces.How you’ll make a difference:Lead BESS Owner's Engineer and technical advisory engagements across feasibility, procurement, contracting, design, construction, commissioning and operation.Establish the BESS sizing and performance basis using the intended dispatch duty, grid requirements, site climate, operating strategy, reliability requirements and lifecycle objectives.Prepare and review Principal's requirements, technical schedules and guarantees covering net power, usable energy, round-trip efficiency, availability, auxiliary consumption, degradation, augmentation, throughput, response performance and reactive-power capability.Lead tender evaluations and normalise competing offers by interrogating assumptions, exclusions, operating limits, warranted curves, design margins, augmentation strategies, lifecycle costs and technical risks.Support contract negotiations on performance guarantees, test and acceptance methods, warranties, liquidated damages and remedies, scope interfaces, long-term service obligations, operations and maintenance, and augmentation responsibilities.Review BESS architecture and interfaces across cells, modules, racks, containers, battery management systems, energy management or plant control systems, power conversion systems, medium-voltage systems, thermal management, fire safety and the grid connection; coordinate specialists and mentor team members.
