Biogas systems take organic material such as animal dung into an air-tight tank, where bacteria break down the material and release biogas – a mixture of mainly methane with some carbon dioxide. The biogas can be burned as a fuel, for cooking, electricity generation or other purposes, and the nutrient-rich slurry which is left can be used as organic compost for cultivation of crops.
VIBO LTD promotes GGC 2047 biogas systems, designed and developed in Nepal, which range in size from 4 m3 to 50 m3. The larger ones are used for semi commercial scale piggeries, schools and poultry farms. The smaller plants for individual families require dung from a minimum of six pigs or two cows, and many have the household toilet connected as well. A family-sized plant provides enough gas for all cooking needs and in some cases for lighting as well, with a small number of households also using the biogas as fuel for an electric generator. The slurry from digester is spread on fields as a fertilizer or sold to neighbours.
How much does it cost and how do users pay?
Householders pay cash up front for a biogas system. A typical 10 m3 system costs about US$1200 typically 70% for materials and 30% for labour. A government subsidy of US$200 can be reclaimed by the family once the system has been checked and confirmed to be working properly by a MINEE technician. The costs of plants vary because masons can set their own charges for labour, and some householders provide part of the labour themselves to bring down the cost. There is also a variation in the price of materials. The technology in more detail VIBO LTD domestic biogas systems have a cylindrical, domed digester vessel built from brick. They are designed principally to work with cow, pig, human, kitchen manure. But some also use chicken, duck or turkey manure. One basic plant designs are used. The GGC 2047 has a standard, fixed-dome shape. The plant is built so that the waste from the animal pens can be sluiced with water directly into the biogas inlet tank, from where it flows under gravity into the digester. Household toilets are similarly flushed with a bucket down a pipe into the digester. Bacteria decompose the slurry under anaerobic (oxygen-free) conditions, and the biogas which is produced collects under the dome and pushes the digested slurry into an outlet tank. A pipe takes the gas to the kitchen stove, lamps or a biogas electric generator each of which has a pressure gauge. Adapted LPG burners, or specially-designed biogas stoves, are used.
“It’s so much cleaner indoors and out. I got one in 2010 after I saw a neighbor’s – I was really impressed. It’s free energy! And it’s so much quicker to cook a meal for the family – and you don’t get smoke in your eyes the whole time.” I am putting dung to my plant. Western Region Cameroon.
Most families use their own savings to pay for a biogas plant, and typically have to save up for about 18 months.
Objectives and beneficiaries
The objective of this project is to reduce by 70% the emission of methane and other toxic gases into the atmosphere that are resulting from the decomposition of organic matter. The PROJECT will benefit cattle rearers (animal rearers etc).
Strong points of the practice
Cameroon today has over 30 million inhabitants and about 09 million representing 30% of the total population have cattle, piggeries, open air pit toilets, poultry and other animals that create a huge odor and waste water management problem. Twenty out of this active and productive population emits an annual average of 100 tones of green house gases, representing approximately 450,000,000 million tones per year. The rest of the 70% are urban and semi urban dwellers whose emissions per family (07 persons per household) stands at 2.14 tones per year.
The Ministry of energy and water resources (MINEE) partnered with the Netherlands Development Organization (SNV) and Heifer project international to develop a nation wide biogas programme in collaboration with a youth technical and architectural group called Virgin Botanicals ltd (VIBO LTD) , which is turning Cameroon’s waste problem into a source of sustainable clean energy and slurry use in promoting organic farming to mitigate climate change from the above consequences.
– VIBO LTD uses FIVE models of Nepalese GGC 2047 -designed fixed dome biogas plant, with sizes ranging from 4 m3 to 50 m3.
– Plants decompose cattle, pig manure, toilet waste and poultry manure to produce biogas, which replaces LPG, coal, wood and agricultural residues for cooking.
– A typical 10 m3 household system costs about US$1200. Cost paid up front, and a government subsidy is requested to assist household reduce their cost of investments. To encourage more to build biogas plants.
– Between 2009 and 2012 the programme directly facilitated the installation of over 300 biogas systems, which are benefitting more than 80,000 people directly and indirectly.
The trained masons also build significant numbers of plants outside the programme.
– According to CDM methodologies, each biogas system of the household size saves the equivalent of 2.14 tones/year of CO2 emissions by replacing the use of fossil fuels. The programme has cut around 642 tones/year of CO2 equivalent by the end of 2012. The industrial sizes save over 11 tones/year of CO2 emission.
– Households with biogas systems greatly appreciate the reduced smell and easier management of manure.
– Survey showed that women save an average of 1.75 hours/day from not collecting fuel, tending cooking fires and buying cylinder gas.
– Health benefits include reduced indoor air, atmospheric and water pollution from green house gases, cooking fires, stoves, and improved hygiene and sanitation.
– Survey showed average saving of US$30/month on cooking fuel, so biogas plant pays for itself in four or five years.
_ Survey also showed that an average house hold uses about 30 tones of fuel wood per year representing ¼ hectare of forest cut down.
Expected results and benefits for climate change adaptation and mitigation
Biogas digesters cut greenhouse gas emissions by replacing fossil fuels (LPG and coal) for cooking, and by reducing the production of methane from poorly managed manure. They also replace biomass (wood and agricultural residues) for cooking, although this does not contribute significantly to greenhouse gas savings, because the biomass is usually re-grown.
What families appreciate most about biogas systems is having a simple means of managing animal manure, and thus keeping their homes clean and odour-free, with fewer flies. Odourless slurry is more pleasant to spread on crops than raw manure, displacing some use of chemical fertilizers and increasing crop yields.
Biogas plants reduced indoor air pollution, water table and environmental pollution. Relieves smoke from fuel wood, coal and kerosene stoves, improved hygiene and sanitation, and less smell from piggeries, toilets and poultry farms.
ECONOMICS AND EMPLOYMENT BENEFITS
The biogas programme will provide over 50.000 local masons with training and work. Team leaders of each mason group are also given additional business training to help them operate more independently. Nationally there are only 50 locally trained masons 05 women and 10 masons supervisors.
Replicability potential of the practice
POTENTIAL FOR GROWTH AND REPLICATION
There is still a huge potential market for biogas in Cameroon, with over 9 million families raising animals, about half of whom could technically make use of a biogas. VIBO LTD aim is to directly facilitate the installation of a total of 200,000 biogas systems by the end of 2020, and 368,000 in 10 Region of Cameroon by the end of 2030.
The success of the programme to date has shown that relatively small amounts of external funding (for training, management and subsidy) can leverage substantial private investment in biogas plants. VIBO LTD now is looking into ways of making the programme self-sustaining in the longer term, including introducing carbon finance as one source of funding.
VIBO LTD is also exploring the market for medium and larger scale biogas plants to keep pace with Cameroon’s rural development. The biogas from such plants could be used for electricity generation. See picture of a 500kw biogas generator in Yaoundé Cameroon.