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-   -   Biomethane/bio-CNG might make more sense than ethanol (

cRiPpLe_rOoStEr 01-07-2015 01:36 PM

Biomethane/bio-CNG might make more sense than ethanol
Ethanol may seem kinda easier to develop, and also easier to adapt a vehicle to use it, but biomethane/bio-CNG also has its advantages in spite of the tank placement issue and a slight decrease in the payload of a vehicle. While ethanol relies mainly in edible produce (be it sugarcane, sugarbeets, sweet sorghum, corn, wheat, rice, whatever has some high sugar content) as its feedstocks, biomethane can be sourced not just from agricultural produce and residues but also recovered from wastewater treatment plants, landfills, or even biodigesters used to process animal residues in farms and meat-processing plants.

Basically all the same technology developed around fossil Natural Gas/CNG can be easily turned to biomethane/bio-CNG, and when we remember that even some 3rd-world countries use CNG it seems kinda weird that it's not so widely developed in America. In Bolivia, nowadays 80% of the public transport fleet (buses and taxis) run on CNG, and in Venezuela since 2009 at least 50% of all the brand-new vehicles must be capable to run on CNG in order to save gasoline and diesel for export. So, why not turning to bio-CNG instead of extracting shale gas (which has a high environmental impact) or giving dollars away to some random corrupt dictator in a 3rd-world country?

freebeard 01-08-2015 09:44 PM

Because they turn into bottle rockets?

I was prompted to see what's new with Cool Planet. There was a flurry of videos in 201410, but nothing since.

Astro 01-08-2015 11:18 PM

Or we could use bio-methane / bio-cng to run stationary generators to feed the grid rather than coal. Then use electric vehicles charged from that grid as transport.
Much easier to distribute electricity than bottled gas.
The bio fuel could be used where it is created, in bulk, for any economy of scale advantages.
Farmers could have digesters on their property running in a grid interactive mode.
Land fill sites could have bio fuel burning generators on site feeding into the grid.

If all our transport was fuelled by the electricity grid then any technology capable of feeding into the grid could be used to supply energy for transport. Wind, solar, hydro, wave, tidal, geothermal, bio-fuel could all be used. Cars would be as dirty or as clean as the electricity grid.
Then when the next innovation in electricity generation comes along it could simply be plugged into the grid.

I would much rather have the fuel for my car delivered right to where it was garaged and be loaded into the car while i sleep.
Rather than have to travel to a distribution centre (petrol station).
Queue up for ages waiting for my turn at the bowser.
Then stand around in the cold/rain/summer heat waiting for the tank to fill because it can't be left unattended while filling.
Then go in to pay for the petrol and hope i picked a time of the day that the store wasn't being robbed. :eek:

P-hack 01-09-2015 12:14 AM

well, we do have natural gas lines feeding many homes too. I don't have any clue what the distribution losses are there vs electricity (they may keep the pressure low to minimize leakage losses), certainly it would be good for heating/cooking, transportation is a little less clear. They do have @home cng compressors but they use 800 watts to fill up your car overnight and no other comparison points (800 watts overnight is comparable to my EV usage, but I don't know how many btu you can pump overnight). There is also something of a network of cng stations (though folks are complaining of high prices for GGE).

I would hope you get a fair bit of range after pumping cng or bio equivelant for your 8kw.

Here is one with more specifics:

2gphE @ 3hp, roughly 1.2kwh per gallon to pack it into your car, which is 1/33 of the energy content, but you would get 3x the mileage from that 1.2kw in an EV, but we have a glut of bio to try to leverage, and cng has a lot more range typically (and we have a lot of vehicles that could be more easily and cost effectively converted to cng than electric)

quick cost check: nat gas is about $0.57 (usage) for the energy equivalent of one gal gasoline plus $0.12 of electricity to turn it into cng. fixed service fees for nat gas is ~$13/mo and elec ~17/mo fyi, around here.

oil pan 4 01-10-2015 09:48 PM

Don't be so quick to count the US out.
Large industrial food processors in the US have all switched over to run as much bio gas as possible in their boilers.
Plus straight bio gas doesn't burn that well. It is typically burned in boilers at a ratio of 3 parts regular natural gas to 1 part bio gas.

cRiPpLe_rOoStEr 01-11-2015 12:56 AM

In my country, when biomethane is used in stationary applications it's usually not blended with fossil Natural Gas. Also, it can be purified into biomethane in order to keep the same energy density as regular CNG.

oil pan 4 01-12-2015 04:56 PM

Yes the bio gas has to be purified but I don't know what that involves.
Since the large scale industrial food processors use way more methane than they can produce its just cheaper to blend and burn.

Grant-53 01-17-2015 02:23 PM

Here in Upstate New York we are slowly seeing a shift to CNG for fleet vehicles. Diesel conversions are being tried. The big economic question is in production of vegetable oils versus methane. Our state governor has said "no" to hydrofracking natural gas for now.

oil pan 4 01-17-2015 03:28 PM


Originally Posted by Grant-53 (Post 464142)
Here in Upstate New York we are slowly seeing a shift to CNG for fleet vehicles. Diesel conversions are being tried. The big economic question is in production of vegetable oils versus methane. Our state governor has said "no" to hydrofracking natural gas for now.

I think they just want to keep the fuel oil and propane racquet going.

ToddT58 01-17-2015 05:05 PM

I love the idea of biogas. Yes, it need to be cleaned up and the nitrogen stripped out. But, it can be made into "grid quality" methane that can be introduced into the natural gas pipelines.

I visited a chicken farm in Mississippi a few year ago where they were taking the chicken litter (poop) and through anaerobic digestion, converting it into methane. The process ran at 140 degrees F from solar thermal collectors and a wood-fired boiler for cloudy days. They ran diesel generators using about 85% biogas and 15% diesel.

The solids after being digested had an 11-11-11 fertilizer value, much better than just putting chicken litter onto the soil (way too much Phosphorous). The chemist I was visiting with was looking into pelletizing the digested poop to sell it as a fertilizer. Back then, natural gas prices were sky high and the farmer stood a chance at making more money on the processed poop than the chickens who pooped it. And, made electricity!

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