Stack Testing Engineer

Twelve is a new kind of chemical company built for the climate era. Our breakthrough technology eliminates emissions by turning CO2 into essential products. We are a team of scientists, engineers and problem solvers on a mission to fundamentally shift the way the world addresses climate change and lead the transition to a fossil free future with our carbon transformation technology.

Overview

Twelve is a carbon transformation company developing proprietary electrochemical systems that convert carbon dioxide into high-value chemical feedstocks and fuels. The Stack Testing Engineer role sits at the critical juncture between R&D and pilot plant scale-up, supporting the integration and validation of stack-level innovations into operational platforms. This position is responsible for executing structured test protocols, driving data-driven system diagnostics and contributing to the technical roadmap required for commercial electrolyzer deployment.

What You Will Do

The Stack Testing Engineer is accountable for the safe commissioning, operation, and troubleshooting of subscale and full-scale electrolyzer stacks. The role involves detailed process monitoring, real-time data acquisition, and root-cause analysis to validate electrochemical performance and inform stack design iteration. The engineer is expected to work across disciplines—particularly with electrochemistry, reactor engineering, and controls teams—to ensure test integrity, capture failure modes, and enable continuous improvement. Execution of the Management of Change (MOC) process and adherence to safety engineering standards are essential responsibilities.

Key Roles and Responsibilities

• Commission and operate stack test stands, including integration of sensors, power electronics, gas and liquid handling systems, and data acquisition interfaces.

• Develop and execute experimental test matrices that quantify performance metrics such as polarization behavior, current efficiency, pressure drop, gas evolution, and degradation rates.

• Collaborate with materials science, process development, and controls engineering teams to characterize operating envelopes and define optimal steady-state and transient conditions.

• Analyze time-series and condition-based data to diagnose system inefficiencies and recommend modifications to hardware, controls, or operating procedures.

• Author and maintain detailed technical documentation including process flow diagrams (PFDs), piping and instrumentation diagrams (P&IDs), operating procedures, risk assessments, and test reports.

• Lead troubleshooting and design-of-experiments (DOE) efforts to de-risk scale-up and inform system-wide modifications.

• Support safety audits, pre-startup safety reviews (PSSRs), and execution of MOC packages to ensure testing aligns with Twelve’s process safety management framework

General Accountability

This role requires technical ownership of electrolyzer stack testing infrastructure and performance characterization. The Stack Testing Engineer will be accountable for maintaining experimental integrity, ensuring high uptime for testing equipment, and executing test runs that generate statistically significant datasets. The engineer will serve as the primary technical interface between development teams and testing operations, enabling the translation of lab-scale discoveries into scalable engineering solutions with verified operational readiness.

Review of Major Deliverables Required by Stack Testing Engineer Include, but are not Limited to the Following:

• Validated operating procedures for each stack configuration and test platform

• MOC documentation for hardware and control system changes

• Test summary reports capturing experimental conditions, key metrics (e.g., voltage/current profiles, Faradaic efficiency), and failure analyses

• Weekly KPI dashboards summarizing uptime, throughput, degradation rates, and anomaly trends

• Root cause investigation reports and recommended corrective actions

• Detailed feedback to inform mechanical, electrical, and process design modifications

Development of Stack Testing Engineering Deliverables

The Stack Testing Engineer will be responsible for developing comprehensive engineering documentation supporting system design validation and operational readiness. This includes process schematics, mass and energy balances, test protocols, validation plans, control narratives, and calibration procedures. Deliverables are expected to meet engineering quality standards required for auditability and traceability throughout the technology development lifecycle.

Preliminary Testing Execution Plan

The initial phase will focus on commissioning and qualification of electrolyzer stack test stands. The engineer will support pre-operational verification, functional testing of instrumentation and control elements, and execution of baseline stack trials. Subsequent phases will involve parametric testing across operating conditions to evaluate degradation behavior, optimize performance, and validate design changes. All testing activities will be executed under controlled conditions and documented in accordance with EHS, QA, and engineering governance protocols.

Twelve Benefits

• Medical, dental, and vision coverage

• Paid sick days and vacation

• Competitive salary and equity compensation commensurate with experience

• Diverse and inclusive work environment

At Twelve, it's important each employee is compensated competitively and fairly. In alignment with state legal requirements, Twelve conducts exhaustive research to understand compensation markets. A range for the included position is listed below. Be advised, actual offer details are determined by job category, job location, and candidate skill level. 

United States Wage Range: $140,000-$175,000 annually

Please note that some pay bands may have wide ranges of compensation to accommodate candidate's diverse sets of skill levels.

We believe that the unique contributions of each individual is the driver of our success. To make sure that our products and culture continue to incorporate everyone's perspectives and experience we never discriminate on the basis of race, religion, national origin, gender identity or expression, sexual orientation, age, or marital, veteran, or disability status.

Want to work with us but don't see a current opening that fits your background? Submit a general application for Future Opportunities or email us at talent@twelve.co for further inquiries.

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Twelve is committed to the full inclusion of all qualified applicants, and complies with federal and state disability laws.  As part of this commitment, Twelve will ensure that persons with disabilities are provided reasonable accommodations for the hiring process.  If reasonable accommodation is needed to participate in the job application or interview process, please contact our Talent team by email at talent@twelve.co.