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Forum Index : Electronics : Turning a Toyota Prius into a "portable" generator

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Kamak
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Joined: 13/04/2021
Location: Canada
Posts: 150
Posted: 04:42am 11 May 2021
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  Warpspeed said  The problem with compressed natural gas as a road fuel is the cost of compressing the gas.
The gas itself is so cheap its almost free, but to compress it overnight to the several thousand psi required to refill your vehicle is just uneconomic in both Kwh or compressor horsepower.

Its not like propane which is a liquid. Natural gas stays a gas under extremely high pressure.

If you use solar power to drive say a scuba tank compressor, its still not economic. Much more energy efficient to use the same solar power Kw to recharge a vehicle battery direct, and its no slower to do either.

Only people using compressed natural gas in Australia are very large organisations that can get very good rates for bulk off peak electricity. Even then its only marginally cheaper than using diesel fuel.

I have some first hand knowledge of all of this when I worked at the research laboratory of the Gas And Fuel Corporation in Melbourne.


Well, we're in NA. There are not many LNG stations around, but they do exist.

"Natural gas costs significantly less than gasoline or diesel per gallon. For example, the average pump price at utility compressed natural gas stations was $2.37 per gallon in February, whereas the average cost of gasoline in California was $3.24 per gallon, and the average cost of diesel was $3.73 per gallon, according to the Energy Information Administration."


https://afdc.energy.gov/stations/#/find/nearest?fuel=LNG
 
Warpspeed
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Joined: 09/08/2007
Location: Australia
Posts: 4406
Posted: 05:52am 11 May 2021
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Compressed natural gas is always still a gas.

Liquefied natural gas (butane or propane) is sold as a liquid.

The two are a very different.
Edited 2021-05-11 16:01 by Warpspeed
Cheers,  Tony.
 
Solar Mike
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Joined: 08/02/2015
Location: New Zealand
Posts: 1119
Posted: 12:32pm 11 May 2021
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Back in the nineties I used to own an old 4 cyl 1600cc car that ran on compressed natural gas. At the time there were a number of high pressure filling stations around setup like petrol pumps.

A large very thick steel tank fitted in the boot, with a gas line running to engine and filling valve under the bonnet. Standard carb was fitted with an extra venturi device between the carb and air cleaner with gas input from regulator and solenoid valve.
Ignition was fitted with an auto spark advance unit that switched on when running on natural gas. Manual changeover switch on the dash allowed switching from petrol to Gas at will.

Usually start the car on petrol then switch to Gas, didn't have as much power on the road as petrol, going up a steep hill one would switch back to petrol for some extra grunt. Had a range of 100kms, not a problem as you could flick the switch and run on petrol when it ran out.

See none of that now, there are no filling stations anywhere, few LPG ones exist with some cars running on that, mainly taxis.

Cheers
Mike
 
Kamak
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Joined: 13/04/2021
Location: Canada
Posts: 150
Posted: 02:55pm 11 May 2021
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  Warpspeed said  Compressed natural gas is always still a gas.

Liquefied natural gas (butane or propane) is sold as a liquid.

The two are very different.


In NA, those filling stations are liquid natural gas, not LPG (propane). Propane is sold in a lot more retail stations. I'm pretty sure those LNG stations are for commercial fleets. LNG is real high-pressure Liquid Natural Gas and is not liquid propane LPG or butane. The LNG tanks in vehicles here are high compression liquified natural gas tanks LNG.

Taxis in North America still do or did a lot of fleets on LNG, LPG, and now electric.

This is the LPG Propane map of NA. Much more, obviously.

https://afdc.energy.gov/fuels/natural_gas_locations.html#/find/nearest?fuel=LPG


Edited 2021-05-12 01:09 by Kamak
 
Kamak
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Joined: 13/04/2021
Location: Canada
Posts: 150
Posted: 03:30pm 11 May 2021
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  Warpspeed said  Compressed natural gas is always still a gas.

Liquefied natural gas (butane or propane) is sold as a liquid.

The two are a very different.


On second look, you're probably right about the inference that "most" vehicles use CNG as opposed to LNG, as this additional information states that, for the most part, the LNG here in NA is for medium to large trucks going long distances. Taxis must be using CNG. Not to say we couldn't get our hands on LNG for I.C.E. generators.

Cheaper: Fuelling up with LNG costs about 40 percent less than diesel.




https://www.tranbc.ca/2012/07/17/cast-of-b-c-players-fuelling-natural-gas-trucks/
Edited 2021-05-12 07:20 by Kamak
 
Warpspeed
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Joined: 09/08/2007
Location: Australia
Posts: 4406
Posted: 10:07pm 11 May 2021
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  Quote  Cheaper: Fuelling up with LNG costs about 40 percent less than diesel.


Propane is cheaper than petrol (gasoline) too, but all the costs are distorted by road tax.

Natural gas as it comes out of the pipe to suburban homes is incredibly cheap for the energy content. Its the cost of the electrical power to compress it is where the money goes.
The government also do not like the idea of not being able to tax it.
Insurance companies and the fire brigade do not like the idea of fires and explosions caused by people trying to compress it at home themselves.
So basically the Australian Government do not want to know about do it yourself compressed natural gas.

It would be possible to do with a repurposed scuba tank compressor, but it takes a lot of Kw and a lot of hours to fill a tank large enough for a days driving.
As I said earlier, a straight electric vehicle is much more practical and energy efficient, and probably overall safer.
Cheers,  Tony.
 
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