Why pre-screen energy storage engineers before the technical interview
Battery systems fail in ways that other engineering does not tolerate. Thermal runaway is not a downtime event, and the design decisions that prevent it are made long before commissioning, in cell selection, pack layout, cooling and the management system's protection limits. Engineers who have only modelled systems can describe all of it accurately and have never watched a pack behave unexpectedly in the field. A short screen asks about that, and about what happened at commissioning.
What actually matters when screening Energy Storage Systems Engineer candidates
- 01
Technical depth
Probe cell chemistry trade-offs (LFP versus NMC), BMS architecture, SOC and SOH estimation methods, DC versus AC coupling, and command of UL 9540A, NFPA 855 and IEC 62619.
- 02
Work that shipped
Ask which BESS projects reached commissioning: MWh rating, PCS and container vendors, capacity test results against warranty guarantees, and augmentation or throughput plans they authored.
- 03
Diagnosis under uncertainty
Test how they chased down anomalies: cell voltage divergence, unexplained SOH drop, HVAC short cycling, false BMS trips, or PCS faults with thin SCADA data.
- 04
Working across the org
Look for work with EPC contractors, cell suppliers, fire marshals and grid interconnection teams, including how they handled vendor warranty disputes or AHJ permitting pushback.
Pre-screening questions to ask Energy Storage Systems Engineer candidates
12 questions grouped by what they test. Ask the same set in every screen and score answers on a consistent scale, or send them as an async video screen and compare answers side by side.
Cells and thermal
3 questions01Which energy storage technologies are you most familiar with?
Listen forSpecific chemistries or technologies with the trade-offs named in energy density, cycle life, safety and cost, tied to a selection they made.
Technologies listed with no trade-offs, or selection driven by what a supplier recommended.
02Can you explain your experience with battery management systems?
Listen forReal work on protection limits, cell balancing and state estimation, with what they configured rather than accepted as supplied.
Management systems treated as a supplied black box, or no view on how protection limits were set.
03How do you manage thermal design in energy storage systems?
Listen forCooling strategy tied to the duty cycle, with propagation between cells considered and a real temperature measurement that surprised them.
Thermal design described only as adding cooling, or no consideration of propagation between adjacent cells.
Systems commissioned
3 questions04Can you describe a project where you designed or delivered an energy storage system?
Listen forA system that was built and commissioned, with capacity and application stated, plus what changed between design and installation.
Studies or models presented as delivered systems, or no involvement beyond the design stage.
05Describe your experience with grid-connected and off-grid storage.
Listen forGrid code obligations and connection requirements understood for grid-tied work, with the different constraints of islanded operation named.
Treats the two as interchangeable, or no awareness of grid connection requirements in the relevant market.
06How do you approach maintaining and upgrading existing installations?
Listen forReal operational work including capacity testing and module replacement, with how they handle mixing new cells with aged ones.
No operational experience after commissioning, or no awareness of the problems in replacing modules in an aged pack.
Diagnosing in the field
3 questions07Describe a challenging technical problem you encountered and how you solved it.
Listen forA field problem such as imbalance, unexpected fade or a management system fault, with the diagnosis path rather than the fix alone.
Problems described from simulation, or a fix applied with no confirmed cause.
08What is your experience with lifecycle assessment of storage systems?
Listen forDegradation modelled against real duty cycles, with a warranty or performance guarantee they had to substantiate or defend.
Lifetime taken from a datasheet, or no consideration of how the actual duty cycle affects degradation.
09Which performance indicators do you track in energy storage systems?
Listen forRound-trip efficiency, capacity retention and availability tracked over time, with a trend they caught before it became a failure.
Monitoring limited to whether the system is running, or no baseline against which degradation is judged.
Grid and safety teams
3 questions10How do you ensure safety and compliance in energy storage projects?
Listen forNamed standards with a real design consequence, such as spacing, suppression or a chemistry rejected on safety grounds.
Standards recited with no design impact, or safety treated as a certification obtained at the end.
11Can you discuss integrating storage with renewable generation?
Listen forControl strategy across generation and storage, with the forecasting or dispatch logic that determined how the system was actually used.
Integration described as connecting components, with no control strategy or dispatch logic considered.
12How do you assess the economic feasibility of a storage project?
Listen forRevenue stack and degradation cost modelled together, with a project they advised against because the economics did not hold.
Feasibility judged on capital cost alone, or no example of recommending a project not proceed.
How to score responses
Score every candidate on the same four criteria immediately after the screen. At this stage you are shortlisting for panel interviews, not making the final call.
Technical depth
35%5Explains degradation mechanisms and round-trip efficiency losses numerically, and cites specific clauses of NFPA 855 or UL 9540A from real project work.
Work that shipped
30%5Names commissioned sites with MW/MWh figures, measured availability, and their own deliverables such as thermal, protection or EMS dispatch design.
Diagnosis under uncertainty
20%5Walks through a real fault from field data to root cause, naming the measurements taken and hypotheses eliminated along the way.
Working across the org
15%5Describes concrete negotiations with cell OEMs or authorities having jurisdiction and how technical evidence changed the outcome.
Thermal runaway is not a downtime event, and modelling experience never produces a story about one. A one-way video screen asks what happened at commissioning.
Try it on HirevireScreening FAQ
Process basics
How long should a pre-screening round for an energy storage engineer take?
Fifteen minutes across eight to ten questions, answered async. Enough to establish which technologies and scales they have worked at, confirm commissioning experience, and hear one thermal or degradation problem.
How much should scale matter?
A great deal. Residential, commercial and grid-scale storage differ in thermal management, protection, grid code obligations and safety regime. Ask what capacity they have worked at rather than reading storage experience as portable across all three.
Evaluating answers
What is the strongest signal when screening a storage engineer?
A thermal or degradation problem observed in a real installation. Engineers who have operated systems describe unexpected cell behaviour, imbalance or capacity fade and what they changed. Modelling experience produces designs that always behaved as predicted.
How do I judge safety answers?
Ask what a design decision cost them. The useful answer names a standard and a real consequence: spacing, suppression, enclosure or a cell chemistry rejected. Standards recited with no design impact mean safety was somebody else's responsibility.
Go deeper on this role
Sanat has been hiring since 2012 and watching the recruitment industry change up close ever since, and turned that screening process into Hirevire's video screening platform. LinkedIn
