---
title: 'Senior Mechanical Engineer, Systems Mechanical Design at Critical Energy'
canonical: 'https://feeny.ai/job/senior-mechanical-engineer-systems-mechanical-design-critical-energy-hawthorne-8wqgndw3mda7'
type: 'job'
last_seen: '2026-09-14'
---

# Senior Mechanical Engineer, Systems Mechanical Design at Critical Energy

- **Company:** Critical Energy
- **Location:** Hawthorne, CA
- **Compensation:** $140k–$200k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-06-12
- **Last confirmed live:** 2026-09-14
- **Apply:** https://jobs.ashbyhq.com/critical-energy/40b516d9-49f5-491d-8ffd-624629afee01

## Job description

Company Description: 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.

Our Mission: 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!

About the Role: We are seeking a versatile Senior Systems Engineer with experience in mechanical design and fluid dynamics to support the design, development, testing, and optimization of clean energy power generation systems. Collaborating with engineers across the company, this Systems Engineer will take ownership from cradle to grave and help drive the project through completion. This role focuses on mechanical and structural design and integration of power generation systems and components such as heat exchangers, turbines, pumps, cooling & lubrication loops, piping, and other balance-of-plant subsystems. The ideal candidate will combine strong fundamentals and practical product development experience to bridge system architecture, physical layout, and structural integrity, ensuring industry-leading performance, reliability, and integration of complex energy systems. The role will involve collaborating closely with other members of the Systems team in addition to Turbomachinery, Supply Chain, Manufacturing, Field Ops, and others. 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 may be adjusted based on the candidate's qualifications and experience. Experience specifically with power generation or process plant systems is not a requirement but is a significant bonus.

Responsibilities:

- Define system requirements, interfaces, and performance targets related to mechanical structures and fluid systems
- Develop and maintain system-level architecture for mechanical and fluid subsystems
- Perform trade studies to evaluate mechanical configurations, flow architectures, and their impact on system performance and cost
- Integrate components such as pumps, piping networks, valves, heat exchangers, and rotating machinery into the overall system design
- Design structural support hardware for multiple components and sub-systems
- Perform hand calculations using first principles to size components, determine flow rates, estimate stresses, etc.
- Perform finite element analysis (FEA) to evaluate structural integrity of components and subsystems
- Identify opportunities to optimize plant layout to increase construction efficiency, minimize cost, and improve maintainability
- Identify, outline, design, and support component-level and sub-system testing required for risk mitigation
- Assist in the development of test plans and instrumentation strategies to validate mechanical and fluid performance
- Analyze experimental data to refine and improve system design
- Generate technical documentation including system specifications, modeling reports, design trade studies, test analysis reports
- Develop and manage relationships with third-party vendors
- Support Field Ops teams with technical expertise and advice after product delivery and accept feedback on possible design improvements
- Other related tasks as defined by your supervisor that add value to the design needs

Required Qualifications:

- Bachelor's degree in mechanical engineering or related field, or equivalent experience
- 5+ years of proven experience in systems engineering or highly related role, with a strong portfolio of projects involving diverse and integrated machinery
- A solid understanding of and the ability to apply first principles of core mechanical engineering principles, including structural and fluid mechanics, thermodynamics, and material science
- Experience with a modern CAD package and a willingness to immediately self-teach proficiency in Siemens NX
- Excellent analytical and critical thinking skills
- Highly self-motivated with effective communication and team-working skills

Basic Experience:

- Experience with components and sub-systems common to power generation or process plants, like heat exchangers, pumps, turbines, valves, piping, fittings, sensors, and fluid management systems
- Strong intuition for optimizing the layout of a complex system of machinery
- Experience generating 3D models and managing assemblies in CAD while ensuring proper fit and function
- Experience with FEA using commercial software (e.g., ANSYS Mechanical, NASTRAN, Catia)
- You have worked with other engineering disciplines (such as Aerodynamics, Turbomachinery, Dev Test, 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
- Experience creating and maintaining comprehensive design documentation including design reviews and component and system specifications

Bonus Experience:

- You have been part of a team that designed and commissioned a power generation or processing plant
- Proven expertise in Siemens NX / Teamcenter environment
- Experience with computational fluid dynamics (CFD) using commercial software (e.g., ANSYS CFX, ANSYS Fluent)
- Hands-on experience with product development, such as resolving manufacturing issues and analyzing test data to inform design modifications

Compensation:

- Base salary ranges from $140-200k per annum
- Equity options
- 100% company-covered Platinum or HD/HSA (with company contribution) medical
- 100% company-covered dental and vision
- Daily catered lunch
- Several annual social and team building outings

## About Critical Energy

## Company Overview
- **One-liner**: Critical Energy builds factory-made, modular power plants that convert heat into electricity, starting with geothermal and waste heat recovery from data center gas turbines.
- **Entity Type**: Private (Seed VC – II)
- **Headquarters**: Hawthorne, California, USA
- **Founded**: 2024
- **Founders**: Spencer Jackson

## Core Business
- Primary industry: Clean energy, modular power generation, geothermal, waste heat recovery
- Target customers: B2B – energy developers, data center operators, utilities, industrial facilities seeking 24/7 dispatchable clean power
- Mission: “Building an abundant low‑cost clean energy future”

## Products & Services
- **Modular Power Plants**: Shipping‑container‑sized, factory‑built units that convert heat into electricity using a closed‑loop working fluid cycle. Initially deployed for geothermal and waste heat recovery from gas turbines. Custom turbomachinery enables adaptability to varying temperature and resource conditions.

## Market Standing
- **Valuation**: Not publicly available
- **Key Metric**: Total funding raised – $22M (Seed VC – II closed in June 2026, including $3M venture debt from Silicon Valley Bank)
- **Notable Investors/Partners**: Susa Ventures (lead), Upfront Ventures, Susquehanna, Silicon Valley Bank, MaC Venture Capital, Sustainable Investments, Humba Ventures, Scribble Ventures. Advisors include Mike Matson (BCG global geothermal lead), Greg Leveille (former CTO ConocoPhillips), Dave Welch (CEO AttoTude), John Kremer (former exec at Adobe and Chase)
- **Growth Signals**: Headcount of 20 employees (per Built In); team brings 50+ years combined SpaceX experience; recent $22M funding enables scaling from prototype to factory production; targeting weeks‑long installation vs. years for conventional plants

## Competitive Advantages
- **Modular & Factory‑Built**: Standardized hardware lowers construction costs and enables installation in as little as two weeks.
- **Adaptable Turbomachinery**: Custom design works across diverse heat sources and temperature ranges.
- **SpaceX‑Bred Engineering**: Founder Spencer Jackson spent seven years at SpaceX (Falcon Heavy, Starship, Raptor engine); team has deep aerospace and turbomachinery expertise.
- **Low‑Cost Dispatchable Power**: Provides 24/7 clean electricity without emissions or consumables, competing with natural gas peaker plants.

## Strategic Focus
- Current priorities: Deploying first geothermal projects, scaling manufacturing capacity for containerized plants, expanding waste heat recovery partnerships with data centers, and raising additional capital for commercial‑scale installations.

## Why Work Here
- **Culture & Team**: Engineering‑first environment with backgrounds from SpaceX, aerospace, and energy. Flat, fast‑moving startup tackling a hard technical challenge.
- **Location**: Hawthorne, CA (office near SpaceX HQ). Built In lists the workspace as in‑office with some remote options; the careers page supports on‑site collaboration.
- **Notable Perks**: Opportunity to work on physical hardware from concept to field deployment; exposure to cutting‑edge turbomachinery; early‑stage equity potential; direct mentorship from industry veterans.
- **Engineering Culture**: “We’re a group of engineers and innovators … having designed complex systems like rocket engines, turbomachinery, and large‑scale hardware.”

## Sources
1. [criticalenergy.com](https://criticalenergy.com)
2. [criticalenergy.com/who-we-are](https://criticalenergy.com/who-we-are)
3. [builtin.com](https://builtin.com/company/critical-energy)
4. [cbinsights.com](https://www.cbinsights.com/company/critical-energy)
5. [linkedin.com](https://www.linkedin.com/company/critical-energy-systems)

## Other roles at Critical Energy

- [Senior Electrical Engineer, Controls](https://feeny.ai/job/senior-electrical-engineer-controls-critical-energy-hawthorne-8pd5cjajs0mr) — Hawthorne, CA
- [Head of Manufacturing](https://feeny.ai/job/head-of-manufacturing-critical-energy-hawthorne-mmr5njqamna8) — Hawthorne, CA
- [Senior Turbomachinery Mechanical Design Engineer](https://feeny.ai/job/senior-turbomachinery-mechanical-design-engineer-critical-energy-hawthorne-pmmxv3ed1gjt) — Hawthorne, CA
- [Senior Mechanical Engineer, Systems Thermal & Fluid Dynamics](https://feeny.ai/job/senior-mechanical-engineer-systems-thermal-fluid-dynamics-critical-energy-4192wgz9ham7) — Hawthorne, CA
- [Senior Electrical Engineer, Power Systems](https://feeny.ai/job/senior-electrical-engineer-power-systems-critical-energy-hawthorne-021smah4pxhp) — Hawthorne, CA