Geothermal Engineer Jobs in California (NOW HIRING)

Critical Energy is an innovative, early‑stage, venture‑backed cleantech company on a mission to accelerate the global energy transition through abundant, low‑cost clean energy. Founded by an ex‑SpaceX engineer, Critical Energy designs and manufactures factory‑built, modular power plants. These rapidly deployable systems convert heat into electricity using a closed‑loop thermodynamic cycle and can be installed in just weeks.

Critical Energy’s technology delivers high‑efficiency, 24/7 power for geothermal applications and waste heat recovery (including from data center gas turbines), making clean energy practical and cost‑effective for demanding sectors like AI hyperscalers and data centers. Backed by top climate and technology investors, Critical Energy is scaling rapidly.

To build an abundant, low‑cost, 100% clean energy future through groundbreaking geothermal innovation.

We are a team of passionate engineers, designers, and visionaries building cutting‑edge solutions to meet the world’s energy needs with 100% clean energy. We are in the initial stages of development and building our team. This is your chance to join on the ground floor of something big! If you are ready to work at a fun, fast‑paced, groundbreaking organization that is positioned to revolutionize geothermal energy, apply today!

We are seeking an innovative and versatile Senior Mechanical Design Engineer to create new turbomachinery. Collaborating with engineers across the company, this Mechanical Design Engineer will help design our next generation of power‑generating turbine products, taking ownership from cradle to grave and driving the project through completion. This role will focus on mechanical design from piece parts to system integration, with both attention to detail and a broad understanding of the product.

The role will involve collaborating closely with other members of the Turbomachinery team in addition to Supply Chain, Manufacturing, Systems, Field Ops, and others. This role will often be a pivot between teams.

Candidates must be willing to be flexible in their work and be willing to embrace new learning opportunities and expand their comfort zone to benefit the growth of Critical Energy.

The title of this role will be based on the candidate's qualifications and experience.

Direct experience with turbomachinery is not a firm requirement but is a significant bonus.

• Take ownership of the turbomachinery detailed CAD models, layout, and draft drawings per ASME Y14.5 to document and communicate your designs; collaborate with other engineers on checking and reviewing models & drawings

• Find unique design solutions by integrating your own innovations with requirements and opportunities found by other subject‑area experts (such as turbomachinery, fluid systems, electrical systems, and development test)

• Perform hand calculations and structural analyses via finite element analysis to validate your design; collaborate with other engineers on checking and reviewing analyses

• Drive your project to delivery by supporting the fabrication, assembly, and testing of the hardware you have designed; review production issues and proactively hunt for solutions

• Support Field Ops teams with technical expertise and advice after product delivery and accept feedback on possible design improvements

• Develop innovative design concepts for new machines or fluid systems

• Other related tasks as defined by your supervisor that add value to the design needs

• Bachelor’s degree in mechanical engineering or related field, or equivalent experience

• 5+ years of proven experience in a mechanical design role, with a strong portfolio of projects involving complex machinery

• A solid understanding of and the ability to apply first principles of core mechanical engineering principles, including statics, dynamics, fluid mechanics, thermodynamics, and material science as it pertains to system sizing and modeling

• Familiarity with basic design for manufacturing (DFM) principles for 5‑axis, CNC machined and 3‑D printed metallic turbomachinery components

• Familiarity with designing for casting, forging, additive, precision grinding, gear / spline hobbing and similar

• Familiarity with choosing appropriate fastener torques / preloads

• Familiarity with sealing design and choosing corresponding seals

• Familiarity with high‑performance polymers used in bushings / seals

• Proficiency in applying Geometric Dimensioning and Tolerancing (ASME Y14.5)

• Experience with a modern CAD package and a willingness to immediately self‑teach proficiency in Siemens NX

• You have created CAD models of parts that were actually produced and assembled into a machine

• Excellent analytical and critical thinking skills

• Highly self‑motivated; effective communication and team‑working skills

• Experience with assemblies and secondary systems common to engines and generators, like piping, fittings, valves, pumps, sensors, and actuators

• Building and managing assemblies in CAD while ensuring proper fit and function of all individual piece parts—you can set up an assembly in CAD that is both digitally robust and easy to assemble in the real world

• Experience with stress and thermal hand calculations on components and assemblies to ensure they can withstand operational loads and temperatures

• Experience with finite element analysis (FEA) and/or computational fluid dynamics (CFD) software (e.g., ANSYS Mechanical, ANSYS CFX, ANSYS Fluent)

• You have prototype and production level experience with detailed manufacturing drawings with appropriate geometric dimensioning and tolerance (GD&T)

• You take responsibility to personally talk to machinists / technicians about the GD&T on your drawings and then implement their feedback to make the product better

• Your drawings are a cohesive piece of documentation and not just a random assortment of views with dimensions

• You have worked with other engineering disciplines (such as Aerodynamics, Materials, and Manufacturing) to optimize designs for performance, reliability, and manufacturability

• You are effective and respectful in communicating with other engineers even when it is controversial or regarding errors that you have observed or have been observed in your work

• Knowledge of common materials and manufacturing methods; you can look at most objects around you and identify the possible ways they were made and what general type of material they were made from

• Experience creating and maintaining comprehensive design documentation, including design reviews, process specifications, and bill of materials (BOMs)

• In‑depth knowledge of the design and operation of specific types of turbomachinery (e.g., gas turbines, steam turbines, centrifugal pumps)

• You have personally made and assembled metal or plastic parts that were included in a machine BOM and successfully operated

• Experience with rotating machinery and their sub‑components like rotors, stators, bearings, seals, housings/casings, high‑performance shafts, etc.

• Understanding of how to manage leakage flow and its impact on thrust management

• Experience with analyzing static structural, vibration, and fatigue

• Experience with rotordynamics analysis including bearing design and selection

• Hands‑on experience with product development, such as resolving manufacturing issues and analyzing test data to inform design modifications

• Proven expertise in Siemens NX / Teamcenter environment

• CAD experience with mechanical routing and / or surface modeling