Advantages of Biogas

To increase their energy security, nations all over the world are turning to biogas and biomethane.

About biogas.

• The main components of biogas, (a renewable fuel) created by the anaerobic digestion of organic feedstock, are methane (50–65%), carbon dioxide (30–40%), hydrogen sulphide (1-2.5%), and a negligibly small amount of moisture.
• It supports all 17 Sustainable Development Goals of the United Nations and can be transformed into a variety of sustainable transportation fuels.

Variants:

Compressed Bio Gas (CBG):

• High-purity or upgraded biogas is compressed at 250 bar pressure to produce a fuel. Unwanted components such as carbon dioxide, hydrogen sulphide, and moisture are removed (CBG). This can directly power CNG engines and shares many of the same characteristics as compressed natural gas (CNG).
• The fact that it is gaseous makes transportation more difficult and expensive. Therefore, even though heavy engines have been used for short-distance driving, it is thought to be more appropriate to power small-sized vehicles.

Liquified Biogas (LBG):

• Methane derived from biogas can be liquefied by cooling it to -162 degrees Celsius, and the resulting fuel is known as liquefied biogas (LBG) . Because of its greater energy density, less storage space is needed.
• At atmospheric pressure, liquid methane has an energy density that is roughly 2.5 times greater than that of methane at 250 bar and 600 times greater than that of gaseous methane.

Benefits:

Its Eco-Friendly Biogas is definitely a greener option than natural gas.

• Most of the natural gas is extracted through fracking. Fracking is a process where chemicals, water, and sand are forced into the ground to break the rock formations beyond which the natural gas lies. This process causes massive damage to the landscape and ecosystems.
• Production of biogas utilizes already available materials. The process requires no energy and produces no exhaust.

Production of Biogas Reduces

• Organic waste like animal manure, food scraps, and field biomass is produced as a byproduct of agriculture, sludge from wastewater treatment plants, and other types of biodegradable waste that various facilities like slaughterhouses produce.
• The production of biogas brings all of this waste into excellent use and reduces the amount of waste that ends up in landfills and ocean beds.
• Not only the soil pollution is reduced, but there’s also a positive impact on water quality.The degradation of food waste and animal manure produces nitrogen that runs off into the water, pollutes it, and poses serious harm to marine life.

The Generation of Biogas Produces Organic Fertilizer

• The process produces a byproduct that is rich in organic digestate. This byproduct can be used as a supplement or even a substitute for chemical fertilizer.

Cheaper Alternative to Natural Gas

• Although natural gas occurs naturally, the process of extraction, purification, and transportation is quite costly.
• However, the generation of biogas is quite cheap. The setup itself is extremely low cost.
• Even farmers can set up small-scale biodigesters at their farms and use animal manure as a raw material. They can then utilize the biogas to generate electricity to power farm equipment.

Healthy Alternative for Cooking in Rural Areas

• Most people in rural areas use firewood for cooking and heating purposes. Not only is collecting firewood a daunting task, but burning firewood exposes people to harmful dense smoke.
• Biogas, being cheaper and more accessible than natural gas in rural areas, can serve as a healthier alternative in these areas.

Alternate fuel

• Because it has a relatively high energy density, it has the potential to be a practical alternative fuel for heavy-duty road transportation.
• Besides being used in heavy-duty vehicles, it is starting to appeal to the shipping industry.

Creates Circular Economy

• Biogas generation creates a circular economy. The waste that humans and animals produce, including animal manure, wastewater, food waste, and crop residue, is harmful to the environment.
• Biogas generation brings all of this organic waste into use to produce biogas that can be used to generate electricity, for heating and cooking purposes, and also to produce organic fertilizer

Disadvantages of Biogas:

Although the generation of biogas reduces the waste and adverse impact on the environment drastically, burning gas still has some impact on the environment.

Limited Technology to Support Large-Scale Biogas Production:

• There’s very limited technological advancement to facilitate large-scale biogas production. The systems that are used today aren’t the most efficient.
• When you use biogas as a fuel for automobiles, the chances that the engine will corrode sooner than later are quite high, thus increasing the maintenance cost.
• The use of biogas is more suitable for cooking, lighting up lamps, and powering water boilers.

Not Economically Attractive:

• Large-scale production of biogas isn't the most economically viable option. It's quite a challenge to boost the efficiency of biogas plants which makes it difficult to produce this biofuel on a large scale.

Biogas Production is Temperature-Sensitive

• Biogas is produced through fermentation. This means that bacteria are at play here. Bacteria function best at an optimum temperature of 37 degrees Celsius.
• If the temperature drops below that, the bacteria will stop working as efficiently as they should, and this will lower the biogas output.
• Therefore, when the temperature drops low in the winter, biogas plants need aid from external heat sources to maintain the optimal temperature to ensure the output of biogas isn’t affected.

Biogas Production Produces Foul Odour

• Biogas production produces a strong foul odor that's hard to bear, which is why biogas production plants are usually set up farther away from residential and commercial areas.

Biogas isn’t Suitable for Metropolitan Areas

• The energy consumption of metropolitan areas is far more than in rural areas.
• The amount of waste produced by all of the metropolitan areas may not be sufficient to produce enough biogas.
• Therefore, biogas is suitable for rural areas only where the energy requirements aren't too high.

Application of Biogas:

• A variety of environmentally friendly transportation fuels can be made from biogas.
• Biomethane can be converted into other fuels like hydrogen and methanol in addition to being used directly as fuel. The main method of hydrogen production promotes the reforming of light hydrocarbons, especially methane, which accounts for a sizable portion of biogas.
• Gasification involves raising the bio-methane to high temperatures (typically over 600°C) while limiting the amount of oxygen and steam present in the reaction.
• As a result of this procedure, syngas, a mixture of hydrogen and carbon monoxide, is produced. After carbon monoxide is removed, hydrogen is created, and it can be used in fuel cells to produce electricity.
• Syngas can also be used to produce methanol. Methanol is a good fuel because it produces less nitrogen oxide (NOx) and particulate matter than gasoline. Additionally, it can be used as a transportation fuel in place of or in combination with gasoline. It is less expensive than LNG.

The biogas and methanol scenario in India:

• The only biogas-derived transportation fuel for which commercialization efforts have been made is CBG.
• LBG, hydrogen, and methanol cannot currently be produced in India from biogas. The primary causes are:
  • a lack of bulk biogas for such derivatives;
  • Lack of infrastructure for producing and selling these fuels,
  • Lack of efficient as well as the absence of modified car engines. Process economics are being improved through research and development.

Government Initiatives:

• As part of the Sustainable Alternative Towards Affordable Transportation (SATAT) programme, which was introduced in 2018, the Indian government has been encouraging private businesses to build CBG plants and supply CBG to oil marketing firms for sale as automotive and industrial fuels.
• In addition, the Indian government and Niti Aayog have provided roadmaps for promoting LNG, hydrogen, and methanol in order to speed up the transition to green fuels.