An Overview of Biogas, its Benefits and Uses

Biogas, the blue flame gas, constitutes a combination of methane and carbon monoxide, among other gases. It is produced during anaerobic digestion of organic substrates, such as manure, sewage sludge, the organic fractions of household and industry waste, and energy crops. This article covers the benefits and the uses of biogas.

An Overview of Biogas

Biogas is a mixture of methane, carbon dioxide, nitrogen, hydrogen sulfide, and traces of a few other gases (Goswami, Chattopadhyay, Shome, Banerjee, Chakraborty, Mathew & Chaudhury, 2016). It is a value-added product of anaerobic digestion of organic compounds (Rajendran, Aslanzadeh & Taherzadeh, 2012). It constitutes a combination of methane and carbon monoxide, among other gases (Bruno, Gelderman, Lambrechts & Semeijn, 2018). Biogas is produced during anaerobic digestion of organic substrates, such as manure, sewage sludge, the organic fractions of household and industry waste, and energy crops. It is produced in large-scale digesters found preliminary in industrial countries, as well as in small-scale digesters found worldwide (Petersson, & Wellinger, 2009). The treated waste from a biogas plant(bio-slurry) is rich in beneficial microorganisms as well as major and micronutrients (Sangha, 2013).

Despite technological advancements in renewable energy adoption around the world, many households continue to face the challenges of insufficient energy supply (Juma, 2020). According to data from FAO 2017, over 2.4 billion people rely on wood for cooking. The use of wood and charcoal contributes to greenhouse gas emissions while also contributing to deforestation and forest degradation. Therefore, there is a need for alternative sources of energy like biogas for a sustainable environment (FAO, 2017). This kind of energy provides clean cooking solutions as it sustains the environment.

Benefits and Uses of Biogas

The following are the key benefits of biogas:

  1. Biogas system provide a safer and cleaner means of storing excreta, as well as other benefits relating to sanitation.
  2. Cooking, heating, and lighting are all made easier with biogas installation.
  3. In algal photobioreactors, fertilizer (bio-slurry) is produced after the reaction with biogas system.
  4. Biogas is much easier to collect than other fuels like wood and crude oil because it takes significantly less time and effort.
  5. Biogas decreases deforestation and the time and effort required to chop and gather firewood.
  6. Biogas produces no smoke, reducing the health risks associated with burning other sources of energy.
  7. When compared to other fuels, biogas is environmentally beneficial and emits fewer greenhouse gases when burned. During anaerobic digestion, dangerous bacteria in excreta are killed.

The following are the key uses of Biogas:

Biogas is used to power gas lamps, which can be used both home and commercially. A lighting intensity comparable to that of a 25-75W electric bulb can be produced with an efficient biogas lamp.

There are biogas-specific stoves on the market that make the most of the fuel (House, 2011). There are many biogas-dedicated appliances that are widely used. However, one must have the necessary skills to connect the piping from the biogas plant to the kitchen and the utilization of the biogas in cooking.

It can be used in instruments used for water heating, space (room) heating etc.

Alternative gas
It can replace compressed natural gas for use in vehicles and other means of transport as in the ‘Amanda Biogas Train’ that runs on biogas in Sweden. It can also be used in hydrogen fuel cells as well.

Production of Fertilizer

Fertilizer (bio-slurry) is produced in algal photobioreactors that fosters the growth of valuable plant nutrients such as phosphorous, ammonia and nitrogen.


An overview: Bio-slurry  is mainly composed of solid plant materials, water and nutrients i.e. ammonia (NH4+), nitrogen and phosphorous. These nutrients are useful in maintaining soil fertility and enhancing crop production (Sara, 2017). This effluent can be used in various ways that benefit the biogas investor especially in horticulture farming (Rajendran, Aslanzadeh, & Taherzadeh, 2012).

Benefits and Uses of Bio-Slurry

Bio slurry has the following benefits:

  1. It is able to repair the soil structure that has been damaged,
  2. Bio slurry acts as a natural pesticide against crop damaging pests and insects,
  3. Bio slurry also provides for additional nutrition for livestock fodder,
  4. It helps save on plant and livestock maintenance expenses,
  5. It helps reduce the problem of organic waste.

Bio slurry has the following uses:

Development of bio-fertilizers: The digester slurry is high in ammonium and other nutrients that can be utilized as an organic fertilizer

Fishpond fertigation: Slurry is added into fish ponds to enhance the growth of algae. This practice has been found to be better compared to the raw manure.

Animal Supplements: It is used as a partial supplement in the rations of pigs and poultry


Through the increased awareness in making the environment pure and trying to regulate the damage on the atmosphere, biogas production is continually becoming a popular renewable source of energy. To sum up, biogas production needs to be emphasized and campaigned for. This is because biogas production may go a long way towards improving how the society utilizes plant and animal refuse, thereby making the environment safe and clean, economically saving on energy costs, and the disposition of energy wastes the right way.


Bruno, T., Gelderman, C. J., Lambrechts, W., & Semeijn, J. (2018). The promise of Best Value Procurement: Governance and (in) stability of specifications within an innovative biogas project. Journal of Cleaner Production, 172, 1465-1475.

FAO (2018). The future of energy in Kenya.

Goswami, R., Chattopadhyay, P., Shome, A., Banerjee, S. N., Chakraborty, A. K., Mathew, A. K., & Chaudhury, S. (2016). An overview of Physico-chemical mechanisms of biogas production by microbial communities: a step towards sustainable waste management. 3 Biotech, 6(1), 72.

House, S. (2011). Design, construction, and maintenance of a biogas generator. Oxfam GB, Oxford, UK2011.

Juma, I. (2020). Assessing the uptake of biogas as a source of clean energy for cooking by low-income households in Kibera slum, Kenya (Doctoral dissertation, University of Nairobi).

Petersson, A., & Wellinger, A. (2009). Biogas upgrading technologies–developments and innovations. IEA bioenergy, 20, 1-19. Retrieved from

Rajendran, K., Aslanzadeh, S., & Taherzadeh, M. J. (2012). Household biogas digesters. A review. Energies, 5(8), 2911-2942.

Sara, T. (2017). Fact Sheet Biogas: Converting Waste to Energy.

SKG Sangha (January 2013) Biogas Plant Construction Manual. Retrieved from


This article is an excerpt from the book, The Blue Flame: Biogas Training Blueprint.

Suggested Citations in APA
Wanjohi, A.M. (2022). The Blue Flame: Biogas Training Blueprint. Nairobi: Kenya Projects Organization

For inquiries about Biogas installation for Domestic and Commercial use at household and institutional levels, kindly contact KENPRO Support Team or call us at +254725788400.