A photo of a large scale biogas plant

Biogas: The Good And The Not-So-Good Part You Need To Know

Everybody is on edge when it comes to biogas and our environment. The debate around global warming, greenhouse gases, and wind power rages everywhere. 

But this discussion does not show up much because it’s more of an industrial issue. There are many several factors to consider when looking at this topic. Today, we’ll take a look at how the discussion changes when looking at the biogas industry.

Is Biogas Bad For The Environment?

Biogas production does not require an external supply of water or fertilizer, so it does not negatively impact the environment. 

However, biogas production can negatively impact air quality if the gas gets into the atmosphere without being purified first. 

Biogas may also produce unpleasant odors for humans and animals close to it if poorly processed or stored.

What Makes The Biogas?

It is a combination of gases that occur during the anaerobic digestion of organic material, and it consists mainly of methane (CH4). 

Biogas is produced by breaking down organic material without oxygen (anaerobic digestion). It can work directly as a fuel, or into electricity, heat, and transport fuels through processing. 

The biogas can be produced from waste materials from agriculture, forestry, food production, and municipal sources.

The key components of biogas are carbon dioxide (CO2), methane (CH4), and hydrogen sulfide (H2S). 

The composition of biogas greatly relies on its source and the conditions under its production.

Typically, it contains 50-60% CH4 and 40-50% CO2 with trace amounts of hydrogen sulfide, carbon monoxide, and nitrogen.

most materials used to make biogas are;

  • biodegradable wastes generated by businesses, such as the lactose left over from producing milk without lactose.
  • manure and field biomass from agriculture
  • biowaste generated by consumers
  • sludge from wastewater treatment plants
  • spoiled food from shops

Components Of A Biogas

Biogas mainly consists of methane (60%), carbon dioxide (40%), and small amounts of other gases. By displacing oxygen, these can cause suffocation in humans or animals.

Methane

Methane is lighter than air, so it collects in the upper spaces of buildings. At concentrations between 5% and 15%, methane is explosive. 

Still, even at lower levels, it displaces oxygen, meaning people breathing a large amount can die from suffocation even though methane itself isn’t toxic.

Carbon Dioxide

Carbon dioxide usually is heavier than air and will often settle near the floor of a room without any disturbance.

Elevated carbon dioxide levels can cause increased heart rate, respiration, and blood pressure. At higher concentrations, it displaces oxygen in the bloodstream and can lead to unconsciousness or death.

Hydrogen Sulfide

Hydrogen sulfide is a dangerous, flammable gas that emits a rotten-egg odor at low concentrations and eye irritation at high levels.

At high levels, it can destroy your sense of smell and cause respiratory paralysis, meaning that at very dangerous or even lethal concentrations, there is no odor to warn you.

Ammonia

Ammonia is a gas that, because it is lighter than air and has an irritating odor, can cause respiratory tract irritation. It also displaces oxygen in the bloodstream if too much of it is around.

Uses of Biogas

A detailed representation of uses of biogas
Courtesy: PluginIndia

Cooking Gas

The gas from biogas can directly help in cooking purposes. It has a higher calorific value than other cooking fuels like LPG or kerosene, producing more heat than other fuel sources.

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Power Generation 

Biogas can also generate electricity using a technology called Anaerobic Digestion which converts organic matter into biomethane gas. This then burns at high temperatures to generate power. 

This process produces fewer greenhouse gases compared to fossil fuels like coal.

Its Byproduct Can Work As Manure

After the biogas production and digestion, the manure from this process can help as organic fertilizer. The manure helps in the growth of plants and crops. 

This technology is a major advantage for farmers and growers because they can use it to produce good quality crops, which will fetch them a reasonable price in the market.

The manure from biogas production can help you grow crops to create more food products for human consumption.

It Can Function In Hydrogen Fuel Cells

Gasoline and diesel are among the two most common fuels for vehicles today. However, these are not sustainable fuels because they depend on crude oil. 

Biogas can also work instead of gasoline or diesel to produce electricity. The fuel cell converts the methane gas into electricity using a catalyst. This chemical substance promotes a chemical reaction without being consumed. 

The only byproduct of this process is water, and you can recycle it back into nature without harming the environment.

Can Work Instead Of Diesel And Petrol

Biogas is also fuel for vehicles such as buses and trucks worldwide. This helps reduce the transportation sector’s greenhouse gas emissions by replacing fossil fuels with renewable ones like biofuels from waste materials such as municipal solid waste, animal manure, etc. These are less expensive than conventional fuels like petrol or petrol diesel.

Is biogas good or bad?

This question has raised many debates, and the best way to address this is by looking at both the advantages and disadvantages of biogas before we can conclude whether it is bad or good.

Advantages Of Biogas

 Biogas Generation Reduces Soil and Water Pollution

The organic materials processed in an anaerobic digester give off greenhouse gases like methane and carbon dioxide when they decompose at high temperatures. 

You can capture these gases and burn them as fuel or use them as bio-fertilizers for crops. 

However, if these gases are not captured and burned, they can leak out of the landfill into the atmosphere. This can lead to a big source of pollution, contributing to global warming. 

Likewise, processed organic materials can leach into groundwater supplies causing contamination problems that are difficult to remedy once they have occurred.

Biogas Generation Produces Organic Fertilizer

One of the biggest advantages of using biogas is that it produces a valuable byproduct called biofertilizer. Biofertilizer contains nitrogen, phosphorus, and potassium (NPK), essential nutrients plants need to grow healthy roots and leaves. 

This means that when you use biogas as fertilizer, you can grow more crops than you would have otherwise been able to do with chemical fertilizers alone because they don’t contain these nutrients!

Healthy Cooking Alternative For Developing Areas

Biogas is a clean-burning cookstove fuel that can help reduce indoor air pollution in developing countries. 

Indoor air pollution from cooking fires is one of the leading causes of death in developing countries. 

Cooking on an open fire releases smoke, soot, and other harmful pollutants into homes where women and children spend much time preparing meals. 

Burning wood or dung indoors can lead to respiratory tract infections, chronic obstructive pulmonary disease (COPD), and lung.

Reduced Dependency On Fossil Fuels

Biogas reduces the reliance on fossil fuels which are non-renewable sources of energy that are rapidly depleting in quantity and rising in price due to their finite supply worldwide. 

This also means fewer carbon emissions into the atmosphere since you can locate biogas production facilities where you need them most. This reduces the need for long-distance transportation by trucks or trains, which produce greenhouse gases during transport like CO2 and NO.

It Is Cheap And Easy To Set Up

One of the main advantages of biogas generation is that it is relatively cheap to set up and maintain compared to other renewable energy sources like solar panels or wind turbines. 

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This makes it ideal for developing countries where resources are scarce, but there are many people who need access to electricity or heating fuel supplies.

Biogas is Eco-Friendly

Biogas generation reduces the number of greenhouse gases released into the atmosphere. 

Plants reabsorb the carbon dioxide produced during combustion during photosynthesis. 

The methane produced during anaerobic digestion (digestion without oxygen) is an efficient fuel that produces zero emissions when burned.

Biogas Production Creates Jobs

Biogas production creates jobs and reduces pollution, so it is worth investing in if you want to help create more employment opportunities in your community. 

Farmers who have access to biogas plants can sell their food waste to them instead of throwing it away or burning it on their farms. This gives them extra income while keeping their farms clean simultaneously!

Disadvantages Of Biogas

Few Technological Advancements

The first disadvantage of biogas is that there have been few technological advancements since its inception in the late 1800s. 

While other types of renewable energy, such as solar and wind energy, have made great strides over time, biogas has not had much success due to its high cost of production and low-efficiency rates.

Foul Odor Emitted from Biogas Power Plant

If you want to start a biogas plant at home, you must be ready for a foul odor that comes out during digestion. 

The smell can be quite strong and may be unpleasant for some people. This means a biogas plant should always be away from residential areas because of the discomfort it would cause residents.

Weather Dependence

The production of methane gas depends entirely on the temperature and humidity levels of the environment where it is located. 

If there is less heat and humidity, the bacteria will not produce methane, and if there is too much heat, it will kill all the bacteria, causing them to die and stop producing methane gas altogether! 

This makes it difficult for biogas plants to operate efficiently because they depend on weather conditions that no one can control!

Biogas Contains Impurities

The second disadvantage of biogas is that it contains impurities such as hydrogen sulfide (H2S), which can be toxic if inhaled in large quantities by humans or animals alike. 

This makes it difficult to store and transport without proper equipment, which adds additional costs to the production process and further reduces overall efficiency.

Bio-fuel, even after refining and compression, is still impure. If the biofuel generated by your system was used to power automobiles, it could corrode the metal parts of those engines.

This corrosion would lead to higher maintenance costs. This gaseous mix is much more suitable for kitchen stoves, water boilers, and lamps than a liquid one.

The above advantages and disadvantages show that the benefits outweigh the disadvantages. Therefore, it is safety say that biogas is good. 

However, the disadvantages also play a part which means there should be enough precautions when handling biogas production because the emissions are toxic and can cause illnesses.

Can We Produce Electricity From Biogas?

Yes, biogas can be used to produce electricity. It is a mixture of methane and carbon dioxide produced from the anaerobic digestion of biomass. 

It can be used as a fuel for cooking or heating, but it is also a renewable energy source that can be converted into electricity.

The biogas can power micro-CHP (micro combined heat and power) systems. These systems are small enough to fit in residential homes and convert landfill gas, sewage gas, and other forms of biogas into electricity or thermal energy (heat). 

The most common type of biogas is landfill gas which comes from anaerobic digestion at landfills and waste treatment facilities. 

Waste treatment facilities are often located near large cities with a lot of waste production, so they often have access to significant amounts of biogas.

How Biogas Is Turned Into Electricity?

Biogas is converted to mechanical energy through an internal combustion engine called the biogas engine. The mechanical energy rotates an electric generator which produces the electricity.

The biogas engine uses a mixture of biogas and air to generate mechanical energy. As the piston moves down, it creates a vacuum that draws in this mixed fuel source.

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The air-biogas mixture is compressed as the piston moves up, and combustion is efficient because of the high compression ratio that the biogas needs.

A spark plug ignites the compressed air and biogas mixture, then heats rapidly as it expands. 

The expansion of this burning biogas forces the piston down to create a torque that rotates the engine.

The biogas engine exhaust valve opens, releasing the spent air and fuel mixture into a heat exchanger to capture any remaining energy from combustion.

Is Biogas Harmful To Humans?

Yes, biogas can be harmful to humans. Biogas is a mixture of methane and carbon dioxide. 

It has a lower hydrogen sulfide concentration than raw sewage but also contains traces of other organic compounds, such as ammonia, which can harm your intestines and lungs. 

If you breathe too much biogas, you could have trouble breathing or feel dizzy or nauseous.

Here are some other biogas hazards;

Asphyxiation

Storing manure in an enclosed space can cause asphyxiation from biogas.

Even if you think a manure pile is well-ventilated, it can still produce enough methane gas to make the air above it too dangerous for breathing.

Do not enter a facility where manure is stored or one in which there is a suspected biogas leak unless natural ventilation can be relied upon to dilute the explosion hazard.

Airing out a facility does not make it safe since some of the gases produced are heavier than air. 

If you find someone unconscious in such an environment, do not enter it yourself because these same toxic gases may overcome you.

Call the fire department so firefighters wearing self-contained breathing apparatus (SCBA) can safely rescue the victim.

Fire/Explosion

Methane, which forms 60% of biogas, is explosive when mixed with air in concentrations greater than 10%.

Because of the explosion hazards, no open flames should ever be used near a digester. 

Also, equipment such as large engines and electric generators must be specially designed to operate safely inside an enclosed space where flammable gases are being produced.

Explosion-proof equipment and non-sparking tools should be used around digesters, as well as electrical service that is not susceptible to sparks. 

There must also be no smoking near the digester or related biogas lines and equipment.

Disease

Animal manure contains bacteria, viruses, and parasites. Biogas is produced by the anaerobic digestion of manure, which occurs because of the bacteria present in animal waste. 

Some types are pathogenic and can cause infection; if you’re handling such materials, protect yourself from contamination with personal protective equipment.

When working around the digester, it is recommended that you wash your hands before eating or drinking and touching eyes/mouths.

Keeping the digester facility clean will reduce disease hazards, odors, and fly populations.

Safety Precautions When Dealing With Biogas

Manufacturer Warnings: Failure to heed manufacturer warnings and follow safe operating procedures may result in death or severe injury. Contact the manufacturer for service requirements.

Safety Walk-Throughs: A safety walk-through can help you recognize potential hazards and suggest measures to prevent them.

Gas Sensors: Gas sensors may detect explosions, suffocation, and poisonous gas hazards. These include both disposable and electronic sensors.

Electronic sensors must be tested regularly, which may have a vulnerable component that needs periodic replacement. Only qualified people should use them to determine if an area is safe.

Personal Protective Equipment: Farmers should be aware that entering an area where manure is stored without a self-contained breathing apparatus (SCBA) can threaten the health of both workers and the general public.

Conclusion

Biogas is a good step towards curbing climate change. Not only does it reduce the amount of methane expelled into the atmosphere, but it also reduces our reliance on fossil fuels. 

Still, some concerns with using Biogas need to be addressed. Hopefully, the positive effects far outweigh the negatives, and we continue to see many more farms sprouting up near urban areas.

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