This new breed of generator can run on almost any fuel

[C C]

https://spectrum.ieee.org/mainspring-energy

INTRO: It’s January 2030 and your electric heat pump is warming the house while your electric car charges in the garage, all powered by solar panels on your roof and by wind and solar generators at your local utility. It doesn’t matter that it’s been raining for two weeks because your utility is tapping into ammonia produced with last summer’s sunshine. It’s consuming that ammonia in a linear generator.

The linear generator can quickly switch between different types of green (and not-so-green, if need be) fuel, including biogas, ammonia, and hydrogen. It has the potential to make the decarbonized power system available, reliable, and resilient against the vagaries of weather and of fuel supplies. And it’s not a fantasy; it’s been developed, tested, and deployed commercially.

The cofounders of Mainspring Energy, of which I am one, spent 14 years developing this technology, and in 2020 we began rolling it out commercially. It is currently installed at tens of sites, producing 230 to 460 kilowatts at each. We expect linear generators at many more locations to come on line within the next year... (MORE - details)

https://youtu.be/bSPRT1JAXj4

https://www.youtube-nocookie.com/embed/bSPRT1JAXj4

[confused2]

Is the Shannon Miller CEO of Mainspring Energy
https://www.zippia.com/etagen-careers-14...xecutives/
the same Shannon Miller as the gymnast
https://en.m.wikipedia.org/wiki/Shannon_...ics_career
?
No reason why she shouldn't be .. just wondered

[C C]

Is the Shannon Miller CEO of Mainspring Energy 
https://www.zippia.com/etagen-careers-14...xecutives/
the same Shannon Miller as the gymnast
https://en.m.wikipedia.org/wiki/Shannon_...ics_career
?
No reason why she shouldn't be .. just wondered

This one supposedly worked at Tesla Motors before founding the company. Mechanical engineering background instead of gymnast and business.

[Kornee]

Where are the specs re actual Carnot cycle efficiency? Especially *overall efficiency* based on ammonia as fuel?
This free-piston linear generator tech niche market is not a one horse race by any means e.g.: https://www.youtube.com/watch?v=eV7f3tOUEbU

I recall opposed free pistons + air springs design was used as gas generators feeding gas turbines on iirc French locos back in the 1950s.
The free piston design per se dates back to ~ 1928: https://www.mikalsen.eu/papers/FPEreview.pdf

While sliding friction may be very low, those air springs not only take up a lot of space but are necessarily only partially adiabatic and will create waste heat. Plus the need for sophisticated motion synchronization control/electrical power conversion electronics blunts somewhat the 'simplicity' claims.

It's not true that reciprocating ICEs are limited to 'inflexible' fixed compression ratios any more:
https://www.roadandtrack.com/new-cars/ca...s-and-why/
Which could if desired be adapted to an opposed piston design. Driving a normal rotary alternator needing no complex conversion/control electronics.

In summary - any $$$s investor in Mainspring would best watch the overall scene like a hawk and have an easy exit strategy in place.
Lots of actual/potential competitors within just that basic design space: https://en.wikipedia.org/wiki/Free-piston_engine