Renewable power is turning into an increasingly significant issue these days. The world right now depends intensely on coal, oil, and gas for its energy. Non-renewable energy sources like fossil fuels and coal are drawn from finite sources that will in the end diminish, get excessively costly, or be environmentally damaging. Due to the increasing expense of fossil fuels and the threat of climate change, there have been positive advancements in this field.
These advancements have enhanced the interest in cleaner and more economical techniques of renewable energy. However, there are various kinds of renewable energy sources accessible like solar, biomass, tidal, wind, and so on. Each kind of energy has its benefits just as it’s disadvantages.

WHAT IS BIOGAS?

Biogas is a mixture of methane, CO2, and small quantities of other gases produced by the anaerobic digestion of organic matter in an oxygen-free environment.
Biogas is often referred to as green energy, clean energy, and alternate energy sources. This energy is obtained from natural resources, like the sun or the ocean, that are not replenished or otherwise endless. It is an alternative to most of the non-sustainable sources used widely today like coal, fossil fuel, etc.
In many places, Biogas has been generated in both small and large-scale plants for instance a house biodigester that provides cooking gas for an entire family and a large-scale biogas plant that can generate energy for a whole community.

COMPOSITION OF BIOGAS

The precise composition of biogas depends on the type of feedstock and the production pathway, otherwise, it is composed of methane, carbon dioxide, and traces of other gases such as nitrogen, hydrogen sulfide, hydrogen, and oxygen.
On average, biogas contains:
– 55-80% methane (CH4)
– 20-40% carbon dioxide (CO2).
– trace gases, including toxic hydrogen sulfide and nitrous oxide.
This variation means that the energy content of biogas can vary; the Lower Heating Value (LHV) is between 16 megajoules per cubic meter (MJ/m3) and 28 MJ/m3.

TECHNOLOGIES IN BIOGAS PRODUCTION

Biodigesters: These are airtight systems (e.g., containers or tanks) in which organic
materials, diluted in water, are broken down by naturally occurring microorganisms. Contaminants and moisture are usually removed prior to the use of the biogas.
There are 2 main types of anaerobic digesters:

covered effluent ponds for liquid waste, where biogas accumulates under an impermeable cover and is piped for processing.

engineered digesters for semi-liquid wastes, like fermentation tanks, where the waste is mixed and the digestion process can be controlled by heating or cooling, or by adding bacterial mix to enhance the degradation process.
During digestion, 30-60% of the digestible solids are converted into biogas.

Landfill gas recovery systems: The decomposition of Municipal Solid Waste (MSW) under anaerobic conditions at landfill sites produces biogas. This can be captured using pipes and extraction wells along with compressors to induce flow to a central collection point.

Wastewater treatment plants: These plants can be equipped to recover organic matter, solids, and nutrients such as nitrogen and phosphorus from sewage sludge. With further treatment, the sewage sludge can be used as an input to produce biogas in an anaerobic digester.

FEEDSTOCK FOR BIOGAS PRODUCTION

A wide variety of feedstocks can be used to produce biogas. The different types of residue or waste are grouped into four broad feedstock categories: crop residues; animal manure; the organic fraction of MSW, including industrial waste; and wastewater sludge.

Crop residues: Residues from the harvest of Cassava, wheat, maize, rice, other coarse grains, sugar beet, sugar cane, soybean and other oilseeds. This report included sequential crops, grown between two harvested crops as a soil management solution that helps to preserve the fertility of soil, retain soil carbon, and avoid erosion; these do not compete for agricultural land with crops grown for food or feed.

Animal manure: From livestock including cattle, pigs, poultry and sheep. Livestock/ cattle and poultry waste comprise the most utilized substrate for biogas generation. Manure from poultry, dairy cattle, and pigs are largely genuine instances of this waste. This organic matter can be exposed to controlled deterioration to yield great amounts
of bio-methane.

Organic fraction of MSW: Food and green waste (e.g. leaves and grass), paper and
cardboard and wood that is not otherwise utilized (e.g. for composting or recycling).

Wastewater sludge: Semi-solid organic matter recovered in the form of sewage gas
from municipal wastewater treatment plants.

HOMEMADE BIOGAS.

It is interesting to note that biogas can be made at home using a household biodigester. This tool effectively uses your food waste, kitchen waste, and garden trimmings and converts them into Biogas, and manure thereby reducing the production of greenhouse gas methane and household waste. The food waste in crushed form is processed in anaerobic digesters to produce Biogas. This is prime in any entity where food waste management is a hassle.

HOW BIOGAS REPLACES FOSSIL FUEL?

Biogas is carbon neutral hence the environmentally less damaging way of obtaining energy from organic waste matter by eliminating methane emission into the atmosphere. The impact of biogas generation on the environment is much lesser than the impact of fossil fuels, and natural gas. Biogas is extensively used in some rural areas for electricity and cooking. Hence Biogas generation is one of the most effective ways to reduce the use of fossil fuel and greenhouse gas emissions.

The key difference between natural gas and biogas is that biogas is a renewable source. This means that the system can continue running as long as there is organic waste being added. In comparison, natural gas comes from gas deposits underground, and once used, is gone. Another important difference is that biogas also produces a secondary benefit that natural gas cannot: the creation of free, methane-rich fertilizer as a natural by-product. This can either be sold to make an income or used on farm land to improve crop yields.

USES OF BIOGAS

• Biogas is most beneficial in rural areas since there is no access to any other source of energy, where indoor pollution and deforestation are an issue.
• Biogas can be used as a source to generate electricity where the wasted heat is used for other purposes. This is done by fueling an engine generator which in turn produces electricity.
• In many places, especially rural areas it is used as a medium for cooking and heating purposes.
• Biogas can be used for running water pump-set and tube-well engines.
• They can also be used as an illuminant in a metal lantern for domestic and street lighting.
• Biogas can be compressed and used in vehicles as a source of fuel, this fuel is less pollutant and more efficient.

WHERE IS A BIOGAS SYSTEM APPROPRIATE?

Biogas systems are appropriate in remote areas that lack commercial energy sources – such as electricity or natural gas utility providers. They can also be wonderful supplemental energy sources, limiting the amount of commercial electricity consumed. They are most effective in areas where people depend on traditional energy – such as firewood, kerosene, paraffin, or dried animal waste – for their cooking and heating needs.

Biogas systems are well suited for areas with large quantities of organic waste, such as communities with livelihoods centered around farming and raising livestock. Biogas systems are also appropriate in urban and semi-urban areas to generate energy from municipal solid waste (i.e., sewage).

ENVIRONMENTAL BENEFITS

Wrap estimates that UK households, hospitality and food service, food manufacture, retail and wholesale sectors produce around 10 million tonnes of food I’m waste per year. If this was all treated through anaerobic digestion, the industry could generate 11 TWh of biogas – enough to heat 830,000 homes – and cut emissions by 8.8 million tonnes of CO2 equivalent, or 2% of the UK’s annual emissions.
According to the Federal Ministry of the Environment, Nigeria generates some 32 million tonnes of waste per year, among the highest in Africa.

Of the waste generated yearly, 2.5 million tonnes is plastic waste, most of which (70 percent) ends up in landfills, sewers, beaches, and water bodies. Can these be converted to biogas? The answer is Yes! This would help reduce the amount of waste to as low as relatively possible.

When compared to virgin natural gas obtained by drilling into the earth, biogas is clearly a more sustainable option. About 80% of natural gas is extracted by fracking, a process where water, chemicals, and sand are forced deep within the ground to break up rock formations. The fracking process can cause significant damage to ecosystems and landscapes.

Biogas also helps mitigate methane emissions that would have otherwise escaped from landfills or manure lagoons. Using this methane as a fuel dramatically reduces its climate impact by converting it into CO2, which is up to 34 times less potent as a greenhouse gas.

Finally, biogas systems can save lives and improve the overall health of households. Because of its efficiency, biogas puts off minimal emissions. This means there is no indoor air pollution or smoke. In comparison, other popular cooking and heating sources in rural communities such as firewood, kerosene, paraffin, and dried animal waste can produce extremely harmful emissions. These emissions, in addition to contributing to climate change, can ultimately lead to serious health complications and premature deaths within families.

DISADVANTAGES OF BIOGAS

1. Little Technology Advancements: Very little technological advancements have
   been made or introduced for streamlining and making the process cost effective and hence the systems that are currently used are not efficient enough. Hence, even the large scale industrial production of biogas is not shown or isn’t visible on the energy map. Most investors are not willing to put in their capital investments in the production of biogas, although investments could be a possible solution to the problems being faced.
2. It consists of impurities: Biogas goes through many refining processes and yet contains a number of impurities. The metals in an engine can start corroding if this biogas full of impurities is used as a fuel after compressing the biogas.
3. Biogas is not attractive on large scale: Large scale usage of biogas is not economically viable. Enhancing the efficiency of biogas systems is very difficult as well.
4. Biogas is unstable in nature: When methane comes in contact with oxygen, biogas tends to become flammable in nature. This happens because biogas is unstable and hence it is vulnerable to explosions.
5. Not suitable for all areas: Biogas can be used in areas where raw materials are available in plenty. Mostly these are available in plenty in rural areas. So it’s only practical to build biogas plant in rural areas.
6. Affected by weather: Like most of the renewable source of energy, biogas also has temperature effects. The ideal condition for bacteria to act is warm climate. So it is difficult to set up a biogas in areas where the climate is cold.

FUTURE OF BIOGAS

Energy experts claim that compressed biogas could become the fuel of the future due to its virtue of being a clean and renewable source of energy, which is also indigenous. It is also expected to reduce the cost of imports of natural gas.

Europe is producing today 18.4 bcm of biogas and biomethane combined. Calculations show that by 2030, production can double towards 35-45 bcm. By 2050, production can increase at least fivefold from today’s production levels, going up to 167 bcm.India currently hosts Asia’s largest compressed biogas plant at Sangrur in Punjab, while other small and medium-scale plants also exist that produce this compressed biogas or bio-CNG for vehicles and other uses.

China has the largest number of biogas plants, with an estimated 50 million households using biogas. These are mostly in rural areas and small-scale home and village plants.The first UK biogas plant was built in 2011, with the introduction of the government’s Renewable Heat Incentive scheme. According to the Anaerobic Digestion and Bioresources Association, growth saw its first peak in 2016 when 33 new plants were built. In 2020, a Somerset dairy farm owned by Biocow was the first to plug its biogas production directly into the national transmission system.

The U.S. has over 2,300 sites producing biogas in all 50 states: 332 anaerobic digesters on farms, 1,269 water resource recovery facilities using an anaerobic digester, 66 stand-alone systems that digest food waste, and 645 landfill gas projects. For comparison, Germany has nearly 10,000 operating digesters and some communities are essentially fossil fuel-free because of them. Biogas as a fuel at all scales is well established internationally but underutilized as a means of generating energy in Africa

CHALLENGES OF BIOGAS IN NIGERIA

1. Lack of funding
2. Lack of policy
3. Regulatory framework and strategies on biogas
4. Unfavorable investor monetary policy Inadequate expertise
5. Lack of awareness of the benefits of biogas technology among leaders
6. Financial institutions and locals
7. Resistance to change due culture and traditions of the locals.

CONCLUSION

Biogas systems turn the cost of waste management into a revenue opportunity for America’s farms, dairies, and industries. Converting waste into electricity, heat, or vehicle fuel provides a renewable source of energy that can reduce dependence on foreign oil imports, reduce greenhouse gas emissions, improve environmental quality, and increase local jobs. The amount of waste generated per year in Nigeria is enough to produce ample biogas to heat thousands of homes, but this can only be possible if biogas systems are properly set up and provisions are made for homes to own household biodigesters.