Senior Sales Engineer
Mainspring Energy· startup· Energy· Mar 3, 2026 · 8mo agoPosted 238 days ago
Menlo Park, CA
Remote
Full-time
Senior
$170K–$200K
7+ years exp
Before you apply
Ghost Signal:
Open since March 3, 2026 — 238 days, and still accepting applications.
Job description
About Mainspring
Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.
The core values that ground our work, guide our decisions, and connect us together:
Pragmatic Optimism
Excellence without Ego
Proactive Collaboration
The Senior Sales Engineer - Grid Scale reports to the Senior Sales Engineering Manager and serves as a senior technical contributor within the sales cycle for solution architecture, estimating, and system integration strategy on Mainspring's largest deployments: sites of 10 MW and above that either connect directly to the grid or serve large load sites such as data centers.
As a member of the Sales Engineering team (a subset of Project Delivery), this role exercises independent technical judgment to develop cost-optimized, execution-ready multi-MW plant solutions aligned with Mainspring's linear generator capabilities. The Senior Sales Engineer is accountable for architectural integrity, commercial rigor, and seamless transition from concept through execution, including a clean handoff of the design basis, estimate, and scope assumptions to Project Management and Project Engineering at contract award.
Responsibilities
Technical Ownership & Architecture Leadership
Develop plant-level system architecture, preliminary designs (site layouts, single-line diagrams, medium-voltage collector and step-up transformer configuration, and point of interconnection scope), and cost estimates from concept through execution handoff.
Articulate and support sound technical approaches, ensuring appropriate design integration and tradeoff evaluation (e.g., MV voltage selection, unit block sizing, redundancy and availability, grid-forming vs. grid-following operation).
For large-load and data center sites, define at the proposal stage how the plant serves and protects the load, including islanding, load-following, black start, and transfer schemes.
Define plant controls, communications, and protection scope (PPC, SCADA/EMS, utility telemetry, protective relaying, revenue metering) and the grid code (IEEE 1547/2800), ISO/RTO, and NERC requirements that drive equipment selection and cost.
Delivery Discipline & Commercial Rigor
Produce complete, accurate, and timely proposal packages, including responses to utility, IPP, and data center developer RFPs, across multiple concurrent projects.
Build well-supported cost estimates covering MV balance of plant, civil/structural, gas fuel systems, and interconnection facilities, proactively communicate risks, and incorporate market inputs into pricing assumptions.
Develop EPC scopes of work and responsibility matrices that clearly split scope between Mainspring, the customer, EPC partners, and the utility, and that carry cleanly into contracts and project execution.
Identify technical and commercial risk in customer specifications and contract terms (performance guarantees, availability, grid code compliance, interconnection cost exposure) and drive resolution before award.
Sales & Customer Engagement
Support customer meetings, site walks, and solution presentations as the technical subject matter expert with utilities, IPPs, data center developers, and EPC partners.
Communicate technical concepts in clear, structured, and solution-oriented formats across customer and internal stakeholders.
Interconnection & Site Feasibility
Support the interconnection team on early-stage applications by supplying plant data, single-lines, and equipment models; interpret Feasibility, System Impact, and Facility Study results and reflect network upgrade and interconnection facility costs in pricing.
Evaluate site constraints that affect plant feasibility and cost, including gas fuel supply (pressure, flow, delivery infrastructure), power density and layout, hazardous area requirements, and air permitting.
Cross-Functional Collaboration
Collaborate with Engineering, Product, Controls, Commissioning, Interconnection, Supply Chain, and Project Management to support technical feasibility and execution alignment.
Contribute to peer design reviews to share technical perspective and strengthen overall solution quality.
Feed lessons learned from grid-scale pursuits back into reference designs, estimating tools, and proposal templates.
Qualifications
Bachelor's degree in Electrical/ Mechanical/ Systems/ Energy Engineering (power systems emphasis preferred)
7+ years of experience in sales engineering, applications engineering, front-end engineering development (FEED) or cost estimating within electrical power systems or related industries, including at least 2 years supporting grid-scale (10 MW+) generation or storage projects, either grid-connected or serving large loads such as data centers
Experience in solar, batteries, fuel cells, microgrids, reciprocating engines/gensets, modular generation packages, or related technologies preferred
Familiarity with electrical power systems, three phase inverters, protection relays, and the physics of grid integration.
Working knowledge of medium-voltage (5 kV+) plant electrical systems, including collector systems, step-up transformers, gen-ties, switchgear, and the plant-side interface to the utility substation or point of interconnection.
Familiarity with utility interconnection processes (Feasibility, System Impact, and Facility Studies) and applicable standards and grid codes (NEC, NESC, IEEE 1547/2800, ISO/RTO requirements, NERC reliability standards).
Experience estimating balance of plant and EPC scope for multi-MW facilities, including MV equipment, civil/structural, and fuel systems.
Strong understanding of standard electrical drawings such as wiring diagrams, electrical schematics, one-lines, P&IDs, and civil site plans.
Ownership Mentality: Proactive in identifying risks and comfortable advocating for the resources needed to solve them.
Ability to travel nationally (~25%)
Nice to Haves:
Power systems study experience or familiarity with tools such as PSS/E, PSCAD, ETAP, SKM, or CYME (load flow, short circuit, arc flash).
Plant-level controls experience: power plant controllers, SCADA/EMS, DERMS, including microgrid black start, islanding, and load-following.
Familiarity with large-scale gas fuel systems (natural gas, biogas, or hydrogen) and hazardous area classification (NFPA, Class I Div 1/2).
Prior experience with an EPC contractor, utility, or IPP on large generation projects.
Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.
In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.
This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.
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