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Natural gas microturbines. Fascinating.

A few years back I was looking into which publicly traded microturbine companies would be able to capitalize quickly with a Stirling Cycle Turbine engine. I believe Capstone [CPST] even had one for sale on their website. But it is scrubbed now.

I found a reference to this project here:

https://www.engr.colostate.edu/~marchese/mech337-10/epri.pdf

BSR discussed this
possibility with Capstone Turbine Corporation about two years ago. While it was too early to
progress with the idea at that time, BSR has not lost sight of the waste heat or exhaust fuel
option.
BSR estimates a long lifetime for the SUNPULSE ™ engine, due to the relatively low operating
temperatures and low operating frequency. Use of air as the working fluid also eliminates the
requirement of a hydrogen or helium bottle typically needed for recharging. The SUNPULSE ™
products are still in the early stages of development; thus, physical and operating specifications
have not yet been determined. BSR estimates a market entry (or breakeven) production volume
of less than 250 units per year, with a manufacturing cost of $600-750 per kilowatt.
Table A-4
BSR Solar Target Specifications – SUNPULSE™ Engine
Product Engine
Product Status Design/Lab Stage, May Have a Single Unit in Testing
Engine Type Free-Piston
Cylinders / Power Pistons One
Working Fluid Air
Hot End Temperature 200-900 ºF
100-500 ºC
Power Output 5-10 kWe AC
Fuel Solar Radiation, Waste Heat, Natural Gas
Electrical Efficiency 35%
(LHV Fuel In to AC Electricity Out)
Production Cost $600-750/kWe @ 250 units per year
EPRI Perspective
BSR’s low-temperature philosophy and Stirling engine design is unique compared to other
technology developers. While the company is still in the early stages of development and has
not yet tested large numbers of systems, early results from the first natural-gas-fueled
SUNPULSE ™ demonstrator are very promising. The BSR technology bears watching.