About Stem - Driven by human and artificial intelligence – Stem is unlocking energy intelligence.

Stem is a global leader reimagining technology to support the energy transition. Turning complexity into clarity, and potential into performance.
We help asset owners, operators and stakeholders benefit from the full value of their energy portfolio by enabling the intelligent development, deployment, and operation of clean energy assets. Our integrated software suite, PowerTrack, is the industry standard and best-in-class for asset monitoring, supported by professional and managed services, under one roof. Meant to tackle challenges as seamlessly as possible, Stem shows the information needed clearly and accurately and helps harness raw data to inform actionable insight. With global projects managed in 55 countries – from Germany to Japan and across North America – customers have relied on Stem for nearly 20 years to maximize the value of their clean energy projects.

Stem’s culture embodies diversity & inclusion beyond the traditional facets of gender, ethnicity, age, disabilities, and sexual orientation to include experience, personality, communication, work styles, and more. At our core, Stem is at the momentous intersection of clean energy and software technology where diverse ideas, experiences, and professional skills converge to make the inclusive culture we have today. Together, we are turning old school thoughts about software and energy into progressive, collaborative, and innovative solutions. By joining our team, you will be collaborating with data scientists, energy experts, skilled salespeople, thought-leading executives and more from a range of backgrounds. This intersection of ideas, beliefs, and skills is what makes us unique enough to lead the world’s largest network of digitally connected energy storage systems.

About the role

As a Senior Controls Engineer (m/f/d) at STEM GmbH, you will work at the intersection of software, control systems and clean energy technology. As part of our Delivery team (Project Engineering and Project Management), you will own the controller and EMS solution on our PV, BESS and Hybrid projects — from control concept and grid-code requirements through commissioning and handover. Our controller is built in CODESYS and simulated in MATLAB/Simulink; you will parameterise and optimise it for each project, drive controller certification processes in Europe, and provide and defend the DIgSILENT PowerFactory and PSS/E models our utilities and grid operators (EVUs) require. You will also be the go-to controls expert supporting our project engineers. At the same time, you will be the key technical interface to our Dev team, translating project and field requirements into product improvements. A senior, high-ownership delivery role with a strong link to product development, in a collaborative, internationally connected team.

What you'll do

▸     Own the controller and EMS solution for PV, BESS and hybrid projects within the Delivery team, from design phase through commissioning and handover

▸     Adapt, parameterise and optimise our CODESYS-based controller and broader EMS functionality (e.g. dispatch, curtailment, asset coordination) to project-specific and grid-code requirements, including PPC tuning of ramp rates, frequency response, Q(U)/Q(P) curves and curtailment setpoints

▸     Prepare and execute project-specific controller simulations in MATLAB/Simulink and pre-commissioning validation using our SiL/HiL test environment, in coordination with Dev

▸     Lead controller tuning during commissioning, including grid-compliance and performance tests, on site or remotely

▸     Support project engineers in troubleshooting complex controller and plant behaviour — including signal path tracing, log analysis, protocol-level diagnostics and systematic root-cause identification

▸     Support integration of the controller with SCADA, grid operator interfaces and communication protocols (Modbus, IEC 61850, IEC 60870-5-104)

▸     Create project documentation such as control concepts, functional specifications, test protocols and commissioning reports

Qualifications

Required

✓     Degree in Control Engineering or Electrical Engineering

✓     5+ years of professional experience in power plant control, project engineering or commissioning of utility-scale PV, BESS or hybrid power plants

✓     Hands-on experience with CODESYS (IEC 61131-3) and controller simulation in MATLAB/Simulink

✓     Experience preparing or supporting simulation models for utilities in DIgSILENT PowerFactory and/or PSS/E

✓     Solid understanding of control theory, power plant controllers (PPC) and EMS/PMS functionality beyond the pure controller function (e.g. dispatch, curtailment, asset coordination)

✓     Track record supporting or leading controller certification processes and grid code compliance topics

✓     Proven commissioning experience and confidence in direct technical interaction with customers and grid operators

✓     Proven, hands-on troubleshooting skills — you isolate and fix controller and integration issues, not just describe them

✓     Fluent English communication skills (written and spoken)

A Plus

✓     Experience in project-driven environments with responsibility for scope, timelines and stakeholders

✓     Familiarity with international grid codes and standards (e.g. VDE-AR-N 4110/4120, ENTSO-E RfG, FGW TR8), ideally including at least one non-European market

✓     Familiarity with communication protocols (Modbus, OPC-UA, IEC 61850, IEC 60870-5-104, DNP3) and protocol-level diagnostics

✓     Experience with SiL/HiL testing and Git-based workflows; pre-sales support (scope, effort estimation, feasibility)

✓     Experience mentoring junior engineers and the ability to challenge existing solutions

✓     German communication skills

What we offer

To learn more about Stem, visit our stem.com where you’ll find information about our solutions, technology, partners, case studies, resources, latest news and more. Here are some relevant links:

• Company Overview
• Newsroom
• Insights
• LinkedIn