Here are two interesting pictures. It’s a contrast of opposites.
As you can see, both pictures depict women burning methane in their kitchens.
The photo on the left is a photo from the National Geographic on the perils of fracking natural gas. In this unfortunate case, a nearby fracking operation has changed the water coming from this woman’s tap. It now contains gaseous methane that can be burned, and the results are fairly dramatic.
The situation in the photo to the right, although similar in appearance, is completely different. My compatriot TH Culhane, and his wife (pictured), actually produce the methane (biogas) being burned in the picture from waste generated by their kitchen and toilets.
They then use this gas to run a gas stove they use to cook their meals on everyday (seen below).
How this works
Methane is natural gas. It’s produced when biomass rots. By controlling this decomposition process in a tank, you can extract the methane for use in your home and store it for later use.
Running a biogas system is actually fairly simple.
The system takes flushed waste from your kitchen and toilets, and stores them in a tank for decomposition. As the bio-waste decomposes, methane is released, captured, and stored. When you need to use it, all you do is turn on your stove and light it, just like you would with a gas stove.
Once set up, a biogas system has the potential to be as easy to use and maintain as a septic system.
How much does it produce?
A biogas system is only limited by the amount of waste you produce and the size of your storage tank.
How much gas could a 4-6 person family produce in a day? About a cubic meter of gas. One cubic meter of methane is able to:
- Generate 1.2kW of Electricity. That’s enough power to run a LED bulb (100W incandescent equivalent) for 60 + hours.*
- Fuel a 1 hp motor for 2 hours or a 3-ton truck 2.8 km.
- Fuel a gas stove that cooks three meals for the same family.
When Does it Make Sense to use Biogas?
That’s the big question. The smartest way to leverage biogas is to leverage an existing natural gas or propane system in the home or community. If that exists, adding the capacity to switch between these sources is possible. Also, if a community does have a sewer system, producing methane for heating public buildings, producing hot water, or generating electricity can often be a smart move.
However, does a biogas produce enough at the household level to make it worth the expense of producing it? However, with natural gas at ~$0.35 a cubic meter (more or less depending on where you live), it’s impossible for me to make a blanket recommend that this is a system you should install right now.
There are some situations where it’s easier for me to recommend this solution:
- Necessity. You live in a very remote location and fuel is difficult/expensive to acquire.
- Income and quality of life. The costs of the fuel for cooking is a significant portion of your income or cooking with other fuels generates smoke/toxins in your living area (a situation common across the entire developed world). A DIY biogas system that eliminates this cost, in both urban and rural settings, is a no-brainer.
- Redundancy. This is an attractive backup system for long duration emergency use or anticipation of economic necessity due to a financial collapse (see point 2 above).
I’ll keep thinking about it.
PS: I’ve been buying loads of LEDs recently, due to some amazing sales. For example, it’s possible to buy most types of LED bulbs for less than $10 in places like COSTCO. Snap those up if you find them! At that price, the payback on energy savings is months, not years. Not only that, they don’t heat up as much (keeping cooling costs down) and they last for decades!
PPS: If you are interested in building a system like this DIY, I’ve found an analyst to sift through the literature, experts and plans available to build a short report on the topic. I’ll let you know when it is available.