Win a copy of Permaculture Design Companion this week in the Permaculture Design forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • r ranson
  • Anne Miller
  • paul wheaton
stewards:
  • Jocelyn Campbell
  • Mike Jay Haasl
  • Burra Maluca
garden masters:
  • James Freyr
  • Joylynn Hardesty
  • Steve Thorn
  • Greg Martin
gardeners:
  • Carla Burke
  • Dave Burton
  • Pearl Sutton

electricity from gas?

 
pollinator
Posts: 435
54
hugelkultur tiny house books urban chicken solar
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I don't want to be "that guy" but I have very little knowledge and NO experience with this kind of thing.

Say for example that I create an anaerobic digester to generate biogas. Say I figure out how to build it correctly, and it's functioning optimally.

1. Is there some sort of way of calculating what volume of gas it will produce, and at what rate?
I'm reading Rob Hopkins book, The Power of Just Doing Stuff, and in it, he talks about a place where there are gas lanterns powered by pet waste, which sounds cool, but then he talks about how some lamps have been redesigned to power LED bulbs instead of burning gas, and I'm stuck trying to figure it out.

2. I understand that I can burn it for heating, cooking, lighting, etc. but how do I use it to power a light bulb or charge a cell phone?
3. Doesn't the conversion of energy from one form to another carry some sort of entropy-effect making it less efficient or something?

Would appreciate some insight, or some helpful links or videos.

 
pollinator
Posts: 2283
Location: Kent, UK - Zone 8
179
books composting toilet bee rocket stoves wood heat homestead
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
From my research into biogas digesters scale is really important - if your waste stream is just material from a normal household you might have enough gas to cook some meals, but you won't have enough surplus to run a generator etc... If you have a dairy farm and lots of cows crapping in the dairy house then you can work on a larger scale and probably provide meaningful power to a whole house.

 
steward
Posts: 4618
Location: Zones 2-4 Wyoming and 4-5 Colorado
441
hugelkultur forest garden fungi books bee greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have seen folks power trucks and tractors with wood gas, I am wondering if you could do the same thing?

If you can power an engine you should be able to turn a generator , right?

 
Posts: 254
Location: Virginia,USA zone 6
19
forest garden hunting trees solar greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Yes, you can run a generator, again, based on the volume of production. You may also use LP lamps, And there are also freezers and refrigerators that run on LP gas.
 
Posts: 110
2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Raw biogas is (primarily) about 55% methane and 45% carbon dioxide (in the details, there are small amount of other chemicals like hydrogen sulfide, which needs to get cleaned out). It can be burned at relatively low energy value per unit of volume directly, and so works well for cookstoves, water heating, and can even be burned directly in a low power engine. The carbon dioxide lowers the by-volume usefulness of the biogas as a fuel. In a standard ICE engine, the amount of fuel that can be burned at once is limited by the displacement of the engine (specifically the cylinder), and don't forget to leave room for the oxygen. Carbon dioxide won't burn, so it's just taking up space. Woodgas, on the other hand, is primarily a blend of carbon monoxide, which will burn, and hydrogen, which also will burn. So, blend in some oxygen and the whole volume of gas is a fuel. Since the process of creating woodgas involves airflow, the oxygen is already there, so it's pre-blended and ready to go.

Raw biogas can be cleaned to remove impurities (H2S, water, etc.) with relative ease. Removal of the CO2 is a little more difficult, but not horrible. If you use a water scrubbing system, you evidently end up with 96% methane, which is "vehicle grade".

I know I'm late to the party with this, but I hope it helps.

Cheers.

JD
 
Politics is a circus designed to distract you from what is really going on. So is this tiny ad:
A rocket mass heater is the most sustainable way to heat a conventional home
http://woodheat.net
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!