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Forum Index : Solar : how about a Turbine generator? must be better than IC engine..

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poida

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Joined: 02/02/2017
Location: Australia
Posts: 1481

Posted: 08:16am 07 Jul 2026

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wronger than a phone book full of wrong phone numbers

poida

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Joined: 02/02/2017
Location: Australia
Posts: 1481

Posted: 08:38am 07 Jul 2026

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right?
IHI AEROSPACE CO. make one.
2.6 KVA
4.5 L/hour kerosine consumption.
https://gasturbineworld.co.uk/dynajet-microturbine-generator/
https://www.youtube.com/watch?v=wa8kS8EZWmQ

let's do some engineering:
kerosine: 35 MJ/litre

4.5 x 35 MJ = 157 MJ/hour

1 Watt = 1 Joule/second

2.6 KVA is about 2.6 kW with a power factor of 1.0, maybe powering a resistive heater
or a well designed power supply e.g. car charger or Eltek PS or water heater

157 MJ/hour to make the 2.6 kW....

157 MJ/hour = 43.7 kJ/second = 43.7 kW
43kW of fuel to make 2.6 kW of electricity?

show me where I went wrong please.

I think I will stick with the old Gentech
https://gentechgenerators.com.au/products/2-8-kva-honda-powered-petrol-generator/
I bought.

1.34 L/hr at 80% load.
it runs on 92 petrol.

let's do the sums:
33 MJ/Litre for petrol
2.8 KVA x 0.8 = 2.2 KVA = 2.24 kW (sort of)
33 x 1.34 = 44.2 MJ/hour = 12.3 kW
so it's 12.3 kW to make 2.24 kW of electricity.

that turbine might sound sexy but it's thirsty.

wronger than a phone book full of wrong phone numbers

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 3321

Posted: 08:57am 07 Jul 2026

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It seems logical, just one main moving part and no reciprocating motion to deal with.
At high power levels it works brilliantly, eg power-stations and jet engines but as you scale a turbine down efficiency drops significantly.

In the days before reticulated electricity every factory had to have a steam engine to power everything. But the cost of having permanent engineers to keep it running encouraged small factories to try steam turbines as they could run unattended for days at a time.
However even at that size they became known as "steam eaters". Coal consumption was much higher.

Same issue in ships that were too big for diesels. It prompted the development of ever bigger 2 stroke diesels with a waste heat boiler to recover energy from the exhaust.

Chrysler spent over 2 decades and many millions of dollars trying to make an automotive gas turbine. They were almost there, getting the efficiency to about 3/4 of a conventional V8 at full power, though still quite poor at normal driving speeds. And to get that far they needed a large complicated waste heat recovery system.
Then the 1970's oil shock hit, no one wanted a big gas guzzler any more so the project was scrapped.

Solar Mike
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Joined: 08/02/2015
Location: New Zealand
Posts: 1228

Posted: 10:29am 07 Jul 2026

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A few years ago 2016, here in Wellington an outfit called WrightSpeed were attempting retro-fitting one of their EV power trains into old electric trolley buses. They completed one conversion as a trial; for the onboard charger they had a very small jet turbine mounted atop the bus, it looked like a large turbo-charger, this was driving a generator for topping up the enclosed oil cooled Lifepo4 bus battery bank.

I have no idea how efficient this process was, but could just imagine at 5am in the morning this thing starting up as it drove down a quiet street.

No they did not get the contract.

WrightSpeed Bus
Edited 2026-07-07 20:32 by Solar Mike

scruss
Senior Member

Joined: 20/09/2021
Location: Canada
Posts: 105

Posted: 05:37pm 07 Jul 2026

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can't disagree with your numbers, polda. Single-cycle turbines like these are essentially heat generators with a small electrical output tacked on. If you had an application where you could use the very hot exhaust gas for a process, it might make sense.

But it's very loud. This video - IHI Dynajet 2.6 micro gas turbine generator fully start up and shut down cycle at home. - YouTube - has clear traffic noise at the start. Notice how that noise seems to go away when the turbine spools up? Ouch.

As for Wrightspeed and their "jet propelled bus": they abandoned that years ago, but not after lots of hype and TED talks. They now offer more sensible electric retrofits, although their website is very light on actual products. Wright, seemingly, is an early Tesla guy who left the company, so maybe the loose connection to reality rubbed off on him.

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