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Mainspring Energy

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Mainspring Energy

mainspringenergy.com

Company research

Public company, workplace, funding, and market signals

Updated Aug 5, 2026

Overview

Mainspring Energy is a privately held power-infrastructure company that designs, manufactures, and deploys firm, flexible, fuel-flexible local power for utilities, data centers, commercial/industrial users, EV charging, and microgrids. Commercial shipments began in 2020; the company reports hundreds of megawatts in field operations and advanced development.

Primary product

Mainspring Linear Generator: a modular, dispatchable, flameless linear-generation system that converts gaseous fuels directly into electricity. It supports natural gas, biogas/RNG, propane, field gas, and hydrogen; operates at approximately 46% efficiency, delivers near-zero NOx emissions without aftertreatment, ramps quickly, and can operate independently of or in parallel with the grid.

Founded

2010

Headquarters

Menlo Park, California, United States

Team size

Approximately 400–500 employees (third-party estimate; official headcount unavailable)

Work style

Flexible

Industry

Electric power generation / energy infrastructure

Sub-industry

Distributed energy, onsite generation, clean energy hardware, and microgrids

Offices

Menlo Park, California headquarters and R&D center
Planned manufacturing facility near Pittsburgh International Airport, Findlay Township, Pennsylvania

Business model

B2B sale and deployment of modular onsite power-generation systems
Long-term maintenance and service offerings
Power infrastructure projects for utilities, data centers, and commercial/industrial customers
Strategic partnerships and project deployments

Funding

Stage

Late-stage private / Series F

Total raised

$813M

Latest round

Series F · Apr 2025

Latest amount

$258M

Series F

Apr 2025 · General Catalyst

$258M

U.S. Department of Energy manufacturing grant

Oct 2024 · U.S. Department of Energy

$87M

Series E final close

Sep 2022 · Lightrock

$290M

Series D

May 2021 · Devonshire Investors

$95M

People & investors

Leadership

Tom Linebarger

Chairman and Chief Executive Officer

Shannon Miller

President and Founder; previously founding CEO

Adam Simpson

Chief Commercial Officer and Founder

Ryan Fletcher

Chief Financial Officer

Scott Gebicke

Chief Operating Officer

David DeGraaff

Senior Vice President, Engineering

Founders

Matt Svrcek

Co-founder; former CTO

Investors

40 North Ventures
Amazon Climate Pledge Fund
American Electric Power
Bill Gates
Chevron Technology Ventures
ClearSky
CPP Investments
DCVC
Equinor
Fine Structure Ventures
Gates Frontier Fund
General Catalyst
Hanwha Power Systems
Khosla Ventures
LGT Bank
Lightrock
Louis M. Bacon
M&G Investments
Marunouchi Innovation Partners
NextEra Energy
Pictet Group
Princeville Capital
Shell Ventures
Temasek

Work & culture

The company emphasizes ambition, practical problem solving, technical rigor, humility, inclusion, cross-functional teamwork, and hands-on ownership. Careers materials describe a supportive environment in which employees solve difficult engineering and operational problems side by side.

Work style

Flexible

Compensation

Job postings signal location- and experience-adjusted base salary, pre-IPO stock options, and benefits. At least one posting states that offers generally are not negotiated; public evidence does not support a complete compensation benchmark.

Benefits

Medical and other full benefits
Vacation and sick time
401(k)
Pre-IPO stock options
Professional-growth opportunities

Product & market

Pricing

No public list pricing found; project-specific equipment and deployment pricing, with optional or contracted maintenance/service offerings. A reported customer economics signal describes a potential approximately three-year payback versus traditional alternatives in some applications.

Differentiators

  • —Fuel flexibility with seamless switching among multiple gaseous fuels
  • —Dispatchable, fast-ramping local power that can operate grid-parallel or grid-independent
  • —Near-zero NOx and no particulate matter without combustion or aftertreatment
  • —Modular architecture that can be deployed and scaled rapidly
  • —No water consumption in operation
  • —Can provide prime power, backup/bridging capacity, solar firming, grid services, and microgrid support
  • —Designed to transition toward low- and zero-carbon fuels such as biogas and hydrogen

Technology

Linear generators
Flameless low-temperature reaction
Power electronics and skid-mounted inverters
Grid-interactive controls
Microgrids
Fuel-flexible gaseous-fuel systems
Natural gas, biogas/RNG, propane, field gas, and hydrogen
Grid-forming and load-following operation

Customers

Utilities
Data centers
Fortune 500 enterprises
Commercial and industrial facilities
EV charging infrastructure
Hospitals and microgrids
AEP
NextEra Energy Resources
Schneider Electric
Moccasin Bend Environmental Campus
U.S. Air Force / Travis Air Force Base pilot

Competitors

Traditional natural-gas engines
Gas turbines
Fuel cells
Tecogen
Himoinsa
BayEco
Onsite Power

Scale & contact

Estimated revenue

Approximately $100M–$150M annually (third-party estimate; not company-reported)

Signals & risks

Other
Oct 2024

The U.S. Department of Energy selected Mainspring for an $87 million manufacturing grant. The planned Pennsylvania facility represented more than $175 million of total investment and a stated future workforce of more than 600; execution, construction, and ramp-up therefore represent material delivery and capital-scaling dependencies.

Source

Latest news

Mainspring Appoints Former Cummins Chairman and CEO Tom Linebarger as CEO and Founder Shannon Miller as President

PR Newswire / Mainspring Energy · Jun 2026

Tom Linebarger became CEO and Shannon Miller transitioned to President as Mainspring targets growth in utility and AI-data-center power markets.

Mainspring Secures $258 Million in Financing to Scale Linear Generator Business

Mainspring Energy · Apr 2025

General Catalyst led a $258 million Series F; the company said cumulative financing exceeded $800 million.

U.S. DOE Awards Mainspring $87 Million Manufacturing Grant

Mainspring Energy · Oct 2024

The grant supports a large Pennsylvania manufacturing facility intended to produce up to 1,000 linear generators annually.

Mainspring Closes Series E at $290 Million

Mainspring Energy · Sep 2022

Lightrock led the final close of Series E, expanded from an initial $150 million close to $290 million.

3 MW product datasheetAbout and leadershipCareersCompany homepageContactJobs portalLinkedIn company pageNews and perspectivesProduct / technologySolutions
SourcesMainspring About / leadershipMainspring product and technologyMainspring careersMainspring Series F announcementMainspring Series E announcementMainspring Series D announcement2026 CEO transition announcementDOE manufacturing grant announcement

Jobs and careers at Mainspring Energy

92 jobs at Mainspring Energy

Senior Reaction Controls Engineer

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1d ago
Hybrid
Full-time
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Principal Electrical Engineer - Power Plant Integration Lead

On-site
Electrical Engr
Menlo Park, CA
1d ago
On-site
Full-time
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Staff Electrical Engineer - Power Plant Integration Lead

On-site
Electrical Engr
Menlo Park, CA
1d ago
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Senior Staff Electrical Engineer - Power Plant Integration Lead

On-site
Electrical Engr
Menlo Park, CA
1d ago
On-site
Full-time
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Electrical Engineer, Electronics Design

On-site
Electrical Engr
Menlo Park, CA
2d ago
On-site
Full-time
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Senior Field Service Technician (Long Island, NY)

On-site
O&M - Operations and Maintenance
Long Island, NY
3d ago
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Full-time
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Field Service Technician (Long Island, NY)

On-site
O&M - Operations and Maintenance
Long Island, NY
3d ago
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Full-time
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Field Service Engineer

On-site
O&M - Operations and Maintenance
Menlo Park, CA
1w ago
On-site
Full-time
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Embedded Controls Systems Engineering Manager

On-site
On product SW and Sys Engr
Menlo Park, CA
1w ago
On-site
Full-time
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Senior Buyer / NPI Buyer Electronics

On-site
Supply Chain
Menlo Park, CA
1w ago
On-site
Full-time
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Mechanical Drafter - CAD

On-site
Mechanical Engr
Monterrey, Nuevo León
2w ago
On-site
Full-time
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Senior Package R&D Technician

On-site
Product Testing
Menlo Park, CA
2w ago
On-site
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Electrical R&D Technician

On-site
Product Testing
Menlo Park, CA
2w ago
On-site
Full-time
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Field Service Manager

On-site
O&M - Operations and Maintenance
Menlo Park, CA
2w ago
On-site
Full-time
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Sales Director - Public Power

Remote
Behind the Meter Sales
Remote
2w ago
Remote
Full-time
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Senior Originator - Public Power

Remote
Behind the Meter Sales
Remote
2w ago
Remote
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Manager Electronics RMA

On-site
Upgrades
Menlo Park, CA
3w ago
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Full-time
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Senior DevOps Engineer

On-site
Off product SW and Data Sys Engr
Menlo Park, CA
3w ago
On-site
Full-time
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Manager, Technical Writing Team

On-site
Operational Tech and Sys
Menlo Park, CA
3w ago
On-site
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Senior Software Engineer in Test

On-site
On product SW and Sys Engr
Menlo Park, CA
3w ago
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R&D Test Engineer

On-site
Product Testing
Menlo Park, CA
4w ago
On-site
Full-time
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Staff Supply Chain Project Manager

Remote
Supply Chain
Remote
1mo ago
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Senior/Staff Materials Process Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Staff Electrical Engineer, Electronics Design

On-site
Electrical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Electrical Engineer, Electronics Design

On-site
Electrical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
Apply

Embedded System Lab Manager

On-site
On product SW and Sys Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Staff Materials and Process Engineer

On-site
Materials Engineering
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Materials and Process Engineer

On-site
Materials Engineering
Menlo Park, CA
1mo ago
On-site
Full-time
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Director, Reliability Engineering

Hybrid
Product Testing
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Senior Embedded Software Manager

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
Apply

Embedded Software Manager

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
Apply

Director of Channel Sales

Remote
Behind the Meter Sales
Menlo Park, CA
1mo ago
Remote
Full-time
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Senior Software Engineering Manager

On-site
Off product SW and Data Sys Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Principal Mechanical Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Staff Mechanical Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Mechanical Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Mechanical Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Director, Regulatory

Remote
Legal
Menlo Park, CA
1mo ago
Remote
Full-time
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Staff Software Controls Engineer - Site Control

On-site
Off product SW and Data Sys Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Modeling & Simulation Engineer: Controls Integration

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Staff CFD Modeling Engineer

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Staff Mechanical Engineer

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Staff Reliability Engineer

On-site
Product Testing
Menlo Park, CA
1mo ago
On-site
Full-time
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Vice President, Financial Planning & Analysis

Hybrid
Finance
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Staff Manufacturing Process Engineer

On-site
NPI - New Product Introduction
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Staff, Contract Manufacturing & Strategic Partnerships

On-site
Supply Chain
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Account Executive, Oil & Gas

Remote
Behind the Meter Sales
Texas
1mo ago
Remote
Full-time
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Senior Sales Development Associate

Remote
Sales Enablement
Menlo Park, CA
1mo ago
Remote
Full-time
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Staff Software Test and Automation Engineer

Hybrid
On product SW and Sys Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Staff Technical Program Manager, Software Engineering

On-site
Operational Tech and Sys
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Failure Analysis Engineer

On-site
Quality
Menlo Park, CA
1mo ago
On-site
Full-time
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Electrical Engineer - Power Electronics

Hybrid
Electrical Engr
Menlo Park, CA
1mo ago
Hybrid
Full-time
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Mechanical Design Engineer - Electromechanical

On-site
Mechanical Engr
Menlo Park, CA
1mo ago
On-site
Full-time
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Senior Director of Industrialization

Hybrid
NPI - New Product Introduction
Menlo Park, CA
2mo ago
Hybrid
Full-time
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Tax Manager

On-site
Finance
Menlo Park, CA
2mo ago
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Full-time
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Staff Reliability Engineer, Electrical Systems

On-site
Product Testing
Menlo Park, CA
3mo ago
On-site
Full-time
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Staff Mechanical Engineer - Battery Design

On-site
Mechanical Engr
Menlo Park, CA
3mo ago
On-site
Full-time
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Fleet Operations & Analytics Engineer

On-site
O&M - Operations and Maintenance
Menlo Park, CA
3mo ago
On-site
Full-time
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Senior Field Service Technician (Ohio)

On-site
O&M - Operations and Maintenance
Columbus, Ohio
3mo ago
On-site
Full-time
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Field Service Technician (Ohio)

On-site
O&M - Operations and Maintenance
Columbus, Ohio
3mo ago
On-site
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Senior Field Service Technician (Salinas, CA)

On-site
O&M - Operations and Maintenance
Salinas, CA
3mo ago
On-site
Full-time
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Field Service Technician (Salinas, CA)

On-site
O&M - Operations and Maintenance
Salinas, CA
3mo ago
On-site
Full-time
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Staff Supplier Quality Engineer - Special Processes

Hybrid
Quality
Menlo Park, CA
3mo ago
Hybrid
Full-time
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Director, Electrical Strategic Sourcing

Remote
Supply Chain
Menlo Park, CA
3mo ago
Remote
Full-time
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Senior Manufacturing Engineer - DFM

On-site
NPI - New Product Introduction
Menlo Park, CA
3mo ago
On-site
Full-time
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Senior Buyer/Planner

On-site
Supply Chain
Menlo Park, CA
3mo ago
On-site
Full-time
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Senior Mechanical Design Engineer - Electromechanical

On-site
Mechanical Engr
Menlo Park, CA
3mo ago
On-site
Full-time
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Senior Sustaining Controls Engineer

On-site
On product SW and Sys Engr
Menlo Park, CA
4mo ago
On-site
Full-time
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Senior Reliability Engineer, Electrical Systems

On-site
Product Testing
Menlo Park, CA
4mo ago
On-site
Full-time
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Principal Software Architect - AI & Security

Remote
On product SW and Sys Engr
Menlo Park, CA
5mo ago
Remote
Full-time
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Senior Manager of Channel Sales

Remote
Behind the Meter Sales
Menlo Park, CA
5mo ago
Remote
Full-time
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Staff Controls & Automation Engineer

On-site
On product SW and Sys Engr
Menlo Park, CA
5mo ago
On-site
Full-time
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Electrical Engineer - Inverter Systems Integration Engineer, Electrical

On-site
Electrical Engr
Menlo Park, CA
5mo ago
On-site
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Staff Electrical Engineer - Power Electronics

Hybrid
Electrical Engr
Menlo Park, CA
5mo ago
Hybrid
Full-time
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Senior Electrical Engineer - Power Electronics

Hybrid
Electrical Engr
Menlo Park, CA
5mo ago
Hybrid
Full-time
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Director of Customer Success

Hybrid
O&M/Commercial
Menlo Park, CA
5mo ago
Hybrid
Full-time
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Test Engineer, Product Qualification

On-site
Product Testing
Menlo Park, CA
6mo ago
On-site
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Senior R&D Mechanical Technician

On-site
Product Testing
Menlo Park, CA
6mo ago
On-site
Full-time
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Senior Sales Engineer

Remote
Project Delivery
Menlo Park, CA
6mo ago
Remote
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Director of Mechanical Engineering

On-site
Mechanical Engr
Menlo Park, CA
6mo ago
On-site
Full-time
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Staff Mechanical Design Engineer - Electromechanical

On-site
Mechanical Engr
Menlo Park, CA
7mo ago
On-site
Full-time
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Staff Electrical Engineer - Inverter & Grid Integration

On-site
Electrical Engr
Menlo Park, CA
7mo ago
On-site
Full-time
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Senior Electrical Engineer - Inverter Systems Integration Engineer, Electrical

On-site
Electrical Engr
Menlo Park, CA
7mo ago
On-site
Full-time
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End of Line Technician

On-site
Product Testing
Menlo Park, CA
7mo ago
On-site
Full-time
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Senior Controls & Automation Engineer

On-site
On product SW and Sys Engr
Menlo Park, CA
7mo ago
On-site
Full-time
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Staff Technical Program Manager

Remote
Operational Tech and Sys
Menlo Park, CA
7mo ago
Remote
Full-time
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Mechanical Engineering Manager - Electromechanical

On-site
Mechanical Engr
Menlo Park, CA
7mo ago
On-site
Full-time
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Senior Commissioning Technician

On-site
Project Delivery
Menlo Park, CA
8mo ago
On-site
Full-time
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Inventory Associate

On-site
Supply Chain
Menlo Park, CA
9mo ago
On-site
Full-time
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Senior Mechanical Engineer – Continuous Improvement for Mechanical Design & Quality Control

On-site
Mechanical Engr
Monterrey, Nuevo León
11mo ago
On-site
Full-time
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Senior Staff Commodity Manager, Mechanical

Hybrid
Supply Chain
Menlo Park, CA
1y ago
Hybrid
Full-time
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Senior Staff Mechanical Engineer - Electromechanical

On-site
Mechanical Engr
Menlo Park, CA
1y ago
On-site
Full-time
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