African Technology Forum/Forum Africain De Technologie

Biogas Capable of Cooking

by Samuel Alomenu

Wouldn't it be interesting to find out that you could create your own power house? That right in your back yard, you could have a system that you can easily tap gas from for your gas cooker and even electricity to power your house? Well I stumbled upon a very interesting system, called a biodigester and with it, you can harness biogas (methane) from animal and other organic waste which can be burned and the heat utilized. I am going elaborate a little bit on the subject and give you leads as to how you can create your biogas system.

What is biogas?

Biogas is basically made up of methane and carbon dioxide, produced through the anaerobic digestion of animal waste. For the proper digestion of the animal waste, a system is required. For this, a biodigester can be built. With the right temperature maintained at 30 degrees to 40 degrees Celsius, in about two to eight weeks the gas is produced.

How does a biogas digester work?

The simple explanation of a biogas digester is a system that allows the proper conditions for anaerobic digestion to take place. Without the process of anaerobic digestion, methane can't be produced from the manure. Anaerobic digestion [1] is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen, used for industrial or domestic purposes to manage waste and/or to release energy.

Why use a biogas system?

Many benefits can arise with the use of biogas. Biogas becomes a very useful alternative to turn to. For example, as a substitute for the use of liquefied petroleum gas (LPG) in Ghana, considering the recent shortage of LPG in the country [2]. As a gas, it burns faster than firewood and charcoal, and can be very convenient for cooking. Burning methane from organic waste, which is both harmful to our ozone layer and a stronger heat-trapping greenhouse gas than even carbon dioxide itself, means biogas is a safer, cleaner energy to use than many others.

Another benefit is that you can reduce or possibly even discontinue the purchase of LPG or any other kind of fuel for your cooking. A biogas system could serve you for years and save you money.

On a larger note, biogas can be used as a source of electricity, through the use of generators that burn methane.

According to sources [3]:

"30 million rural households in China that have biogas digesters enjoy twelve benefits: saving fossil fuels, saving time collecting firewood, protecting forests, using crop residues for animal fodder instead of fuel, saving money, saving cooking time, improving hygienic conditions, producing high-quality fertilizer, enabling local mechanization and electricity production, improving the rural standard of living, and reducing air and water pollution." [4]

Simple steps to constructing a biogas digester for one’s home

There are different kinds of biogas systems that are built for varying purposes. In this article [5], we can focus on a simple home’s biogas system and how that can be installed. An interesting one to look at is this one from the article in afrigadget.com [6]. It uses very simple materials and pictures of the things needed to construct and install a system in one’s home.

A biogas system when installed for one’s home has many advantages as mentioned above. Its very convenient and goes a long way to reduce the level of methane in the environment, and this further reduces the global warming effect. It helps us realize in many ways the energy reserves in nature and that with some conventional ideas we can tap from these energy reserves and make the world as safer place.

In the links below the main reference section of this article, you will find more information on biogas systems: what to consider when you want to install one, the types of biogas digesters, the financial aspects and some of the other technical issues involved.

References

[1] Anaerobic digestion reference sheet

[2] LPG shortage in Ghana and the way forward

[3] Anaerobic digestion briefing paper

[4] Biogas in China

[5] Solving the flexible biogas digester problems

[6] Poop piki piki for my biogas system

Other links

Biogas:

http://en.wikipedia.org/wiki/Biogas

http://www.oregon.gov/ENERGY/RENEW/Biomass/biogas.shtml

http://en.wikipedia.org/wiki/Anaerobic_digestion