Currents Podcast Ep326: How Linear Generators Empower Businesses

Host: Todd Alexander, Norton Rose Fulbright
Guest: Shannon Miller, CEO, Mainspring Energy
Date: December 4, 2025

Overview

In this episode, Todd Alexander interviews Shannon Miller, CEO of Mainspring Energy, about linear generators—an innovative, fuel-flexible, and modular power generation technology aimed at commercial, industrial, and utility applications. The discussion covers how this technology fits into the energy landscape, its scalability, cost and financing considerations, and real-world deployments.

What is a Linear Generator? (00:23 - 02:15)

• Definition and Technology:
  Shannon Miller explains that a linear generator is a new type of power generator that leverages advances in power electronics and software to create a highly flexible and low-emission power source.
  • “We build a new type of power generation technology called the linear generator... What’s unique about the technology is that, first of all, it’s extremely low emissions, and second, its level of flexibility.” — Shannon Miller (00:39)
  • The generator uses a reaction of fuel and air to drive two tubes with magnets through coils in a linear motion, generating electricity.
  • Software precisely controls this process, offering dispatchability and modularity.

Key Features:

• Modular design
• Fuel flexibility
• Dispatchability (ramp up/down quickly, turn on/off)
• Applicable for commercial, industrial, utility, and data center use cases

Modularity and Scalability (02:27 - 03:56)

• Base Unit:
  Mainspring’s system is designed as a 250kW base module, allowing rapid, factory-based manufacturing and deployment.
  • “You can build them...in a factory and ship them to the customer and then hook them up and get running very, very quickly.” — Shannon Miller (02:50)
• Scalability:
  Customers can scale their installations by aggregating units, offering flexibility to expand from a few megawatts to much larger deployments without inefficiency or major cost penalties.
  • “We can right-size the technology to the customer’s needs...They have that optionality to build what they need today and then expand later.” (03:29)

Fuel Flexibility and Comparisons (03:59 - 04:59)

• The generator can run on a variety of fuels: natural gas, renewable natural gas (RNG), biogas, hydrogen, ammonia.
  • “Our projects today are natural gas, RNG or biogas...we can run on things like hydrogen, also things like ammonia.” — Shannon Miller (04:20)
• Customers may choose fuels based on availability, cost, reliability needs, and sustainability targets.
• Miller compares Mainspring’s product to combined heat and power (CHP) projects and fuel cells but distinguishes it with modularity and real-time fuel flexibility.

Customer Costs and Operating Model (04:59 - 07:24)

• Modeling and Hedging Costs:
  Mainspring works with customers to project accurate operating costs, including opportunities to hedge fuel prices and switch fuels as needed.
  • “We can help the customer model pretty effectively what their costs are going to look like...flexibility builds in a lot more confidence for customers.” (05:40)
• Total Cost of Ownership:
  Generally delivers lower capital, operating, and service costs versus other on-site power options (e.g., CHP, fuel cells, energy storage).
  • “We’re typically going to have a lower total cost of ownership...higher efficiency is going to mean lower fuel costs.” (06:43)

Target Applications and Value Proposition (07:24 - 09:52)

• Initial Focus:
  Started with commercial and industrial customers needing 1–15 MW projects—manufacturing, logistics, cold storage, EV charging.
  • “The use case for the customer is always the same; they need more power than what the utility can give them...and they want reliability.” — Shannon Miller (07:59)
• Expanding to Larger Projects:
  Now piloting with data centers and utilities (10–100 MW), leveraging modularity and rapid deployment.
• Ideal Application Characteristics:
  • Customers with critical reliability needs (e.g., cold storage)
  • Regions with high power prices or capacity constraints
  • Users wanting to add power quickly where the utility cannot meet demand
    • “We target customers that are in regions where the electricity costs are high or where there’s constraints...and they want to have resiliency.” (09:52)

Financing and Project Structures (10:33 - 12:24)

• Financing Models:
  Accessible through direct purchase, energy service agreements, or via partners (e.g., NextEra).
• Eligibility for Tax Credits:
  Projects qualify for the U.S. Investment Tax Credit through 2035.
  • “We do qualify for the investment tax credit and that’s through 2035. So that’s helpful for our customers...” (11:05)
• Flexible Ownership Options:
  Customers can own the equipment or opt for third-party ownership and just buy the energy.
  • “Yeah, that’s typically through a partner today. But, but yeah, we do have that option for customers.” (12:18)

Role in the Power Landscape (12:24 - 14:59)

• Complementary to Storage:
  Linear generators often work alongside batteries (BESS) in microgrids, especially when usage profiles require load leveling (e.g. spikes for EV charging).
  • “We don’t see ourselves really as a competitor to BESS, but really they’re two different tools...the reason the BESS were helpful is because the EVs all sort of come back at the same time and need to charge.” (13:09)
• Integration with Renewables:
  Often paired with solar; generators provide power when renewables are unavailable or loads spike.
  • “In those cases, you don’t necessarily need BESS to support the system. You can use solar and Mainspring as the microgrid.” (14:34)

System Controls and Customer Use (14:59 - 16:13)

• Automated Dispatch:
  Integrates with building management systems to automate operation based on real-time needs.
  • “Typically in the commercial and industrial applications you’ve got a building management system that is dispatching that automatically...” (15:10)

Technology Differentiators (15:51 - 17:18)

• No Special Catalyst:
  The main innovation lies in the design architecture and software rather than a unique catalyst, differentiating it from fuel cells.
  • “The innovation is really in the overall architecture of the system and then in the software and the controls...” (16:13)
• Proprietary IP in Controls/Software:
  Mainspring’s intellectual property largely resides in its software and control systems, enabling efficient, flexible operation.

Product Roadmap and Future Growth (17:18 - 19:21)

• Ongoing Innovation:
  Committed to continuous improvements, cost reduction, and efficiency gains as the technology matures.
  • “We do have a very deep technical product roadmap...there’s lots of room for improvement and driving scale, lowering costs...” (17:18)
• Benefits of Modularity:
  High availability due to distributed, modular architecture; individual unit failures have minimal system impact.
  • “If you have 50 megawatts of linear generators and you have any one module shut down...it’s a much more reliable and available system...” (18:18)
• Strategic Focus:
  Scaling up to serve large utility and data center projects (e.g., 35 MW+), especially where rapid grid expansion and low emissions are critical.
  • “We see a lot of those types of projects coming online in the next few years and really helping to enable both utilities, data centers and commercial and industrial customers manage this need to grow their businesses by getting rid of this constraint around power...” (19:21)

Memorable Quotes & Moments

• “What’s unique about the technology is that, first of all, it’s extremely low emissions, and second, its level of flexibility.” (00:39)
• “The use case... is always the same. It’s they need more power typically than what the utility can give them. They want to save money on their electricity and they want to add reliability to their site.” (07:59)
• “We do have a very deep technical product roadmap...there’s lots of room for improvement and driving scale, lowering costs and continuing to drive efficiencies.” (17:18)
• “One of the benefits of modularity is that you do get really high availability by having a small amount of overbuild...it’s a much more reliable and available system than a much larger individual single module.” (18:18)

Conclusion

Mainspring’s linear generator offers a new, highly flexible, and fuel-adaptable power solution for modern businesses wrestling with grid constraints, reliability, and sustainability. The technology’s modular design, fast deployment, and ability to integrate with renewables and storage make it a compelling tool for commercial, industrial, and now utility-scale applications. Shannon Miller emphasizes a commitment to continual technological improvement, scalability, and enabling customers to thrive as energy needs evolve.

For more episodes and information, visit: projectfinance.law
Contact: currents@nortonrosefulbright.com