Biogas: An alternative energy source in the future
Jul 28, 2020

Biogas: An alternative energy source in the future

The demand for energy is increasing rapidly due to the increase in the population and changes in the lifestyle of the people. The count in the vehicles is also increasing drastically and this has led to a huge demand for fuels like petrol and diesel. These fuels burn and release harmful gases into the environment in the form of smoke that consists mainly of greenhouse gases that are responsible for global warming and air pollution. Scientists, environmental experts have already warned us about the pollution level and increase in the global temperature but the usage of petrol and diesel can be suddenly stopped because the transportation industry is dependent on these fuels and the crude oil industry generates billion-dollar revenue and lakhs of employment across the globe. Vehicles that run on other kinds of fuels like solar and electric batteries are not much efficient and reliable. The domestic LPG used for cooking pollutes less but we may face a shortage in the next 50 - 60 years due to its very high demand.

We permanently cannot rely on fuels like petrol, diesel, and LPG, the only solution is relying on renewable energy resources like solar, wind energy etc. Solar and wind energy may fulfil the demands for generating electricity but we also need to think an alternate energy source for domestic gas. Experts suggest that biogas will be an alternative energy source in the future for heat energy. Biogas is already in use in rural areas but its use is limited due to the availability of limited technology in biogas and cost-effectiveness, considering its reliability very few people are showing interest to use it.

What is Biogas?

Biogas is a fuel that consists of a mixture of gases produced by the breakdown of the organic matter in the absence of oxygen by an anaerobic organism class called methanogens. Methane and carbon dioxide are the primary constituents of the biogas. In India, biogas is popularly known as gobar gas as methane is produced using gobar(cow dung).

The methane gas is also produced naturally in almost every part of the world where organic materials are found in abundance. The major natural source of methane is wetland soil, other sources include oceans, forest soils, termites, and wild ruminants.

Biogas as a fuel:

Scientifically biogas is produced by a process of methanogenesis. Methanogenesis is a process of production of methane by the methanogen which digest the organic materials present inside a closed system in the absence of oxygen. Methanogens digest the organic materials and primarily release methane gas by breaking down the organic compounds into the simple ones. The methane gas released is collected in a cylinder and can be used as a fuel to produce heat energy for domestic cooking. The calorific value of biogas is up to 26 MJ/m3 depending on the quality of digestion compared to the calorific value of LPG with 46.1 MJ/kg. The biogas can be compressed in the same way natural gas is compressed to CNG by removing the carbon dioxide compound from it which is a convenient way for storing in the cylinder.

How biogas is beneficial:

The biogas is ecofriendly as it does not emit a large number of harmful gases upon burning as a byproduct. The other two factors that make biogas beneficial are:

  • It cuts the global methane release into the atmosphere from the wastes.
  • The reliance on fossil fuels to meet global energy demand.
  • The methanogenesis process produces natural fertilizers.

Using organic waste materials for the generation of biogas cuts the global methane release naturally which is also responsible for global warming indirectly. These wastes simply occupy the landfills and pollute the environment moreover these can be utilized for the energy resource.

The biogas will steadily contribute to meet global demand, in populous countries India and China it is used in domestics and right now we have limited technology and not much more feasible for commercial production by considering the cost.

The methanogens digest the organic wastes and leave a byproduct of natural fertilizers that can be utilized in gardening and plantations.

Biogas is already in use:

Biogas can be generated by the process of methanogenesis in a biogas plant. Biogas consists of a digestor chamber and a couple of reservoirs fitted with an input and output valve respectively. In the digestor chamber, methanogens are present and carry out anaerobic digestion by breaking the complex compounds and release methane gas which is then collected in a cylinder. The other solid wastes are still rich in carbon and nitrogen compounds and can be used as a natural fertilizer.

The biogas plant is already in use in many rural parts of India. According to the Government of India, in 2014-15 the estimated production of the biogas was about 20,757 lake cubic meters which are equivalent to 6.6 crore domestic cylinders and make equivalent to 5% of the total LPG consumption. Maharastra and Andhra Pradesh topped in the production of biogas with 3578 lakh cubic meters and 2165 lakh cubic meters respectively.

The Government of India had also set a target to set up 6.5 lakh biogas plants across the country with an estimated budget of Rs.650 crore under the National Biogas and Manure Management Program(NBMMP). The ministry has said that 2.53 lakh families were benefitted with biogas plants until 2015.

The production of methane gas/biogas is not commercially feasible due to less availability of technology and scientific method to control the process of methanogenesis to attain maximum production. Many scientists are working to design a biogas plant that has more efficiency and operates at less cost that can be used for commercial production to meet the industry demand.