What is Biogas? A Beginners Guide Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, break down in an anaerobic environment (an environment absent of oxygen) they release a blend of gases, primarily methane and carbon dioxide. Because this decomposition happens in an anaerobic environment, the process of producing biogas is also known as anaerobic digestion.
Anaerobic digestion is a natural form of waste-to-energy that uses the process of fermentation to breakdown organic matter. Animal manure, food scraps, wastewater, and sewage are all examples of organic matter that can produce biogas by anaerobic digestion. Due to the high content of biogas (typically 50-75%) biogas is combustible, and therefore produces a deep blue flame, and can be used as an energy source.
The Ecology of Biogas Biogas is known as an environmentally-friendly energy source because it alleviates two major environmental problems simultaneously: The global waste epidemic that releases dangerous levels of methane gas every day The reliance on fossil fuel energy to meet global energy demand By converting organic waste into energy, biogas is utilizing nature’s elegant tendency to recycle substances into productive resources. Biogas generation recovers waste materials that would otherwise pollute landfills; prevents the use of toxic chemicals in sewage treatment plants, and saves money, energy, and material by treating waste on-site. Moreover, biogas usage does not require fossil fuel extraction to produce energy.
BIOGAS IS BETTER THAN FOSSIL FUELS
Instead, biogas takes a problematic gas, and converts it into a much safer form. More specifically, the methane content present in decomposing waste is converted into carbon dioxide. Methane gas has approximately 20 to 30 times the heat-trapping capabilities of carbon dioxide. This means that when a rotting loaf of bread converts into biogas, the loaf’s environmental impact will be about 10 times less potent than if it was left to rot in a landfill. Biogas Digesters As opposed to letting methane gas release to the atmosphere, biogas digesters are the systems that process waste into biogas, and then channel that biogas so that the energy can be productively used. There are several types of biogas systems and plants that have been designed to make efficient use of biogas. While each model differs depending on input, output, size, and type, the biological process that converts organic waste into biogas is uniform. Biogas digesters receive organic matter, which decompose in a digestion chamber. The digestion chamber is fully submerged in water, making it an anaerobic (oxygen-free) environment. The anaerobic environment allows for microorganisms to break down the organic material, and convert it into biogas.
All-Natural Fertilizer Because the organic material decomposes in a liquid environment, nutrients present in the waste dissolve into the water, and create a nutrient-rich sludge, typically used as fertilizer for plants. This fertilizer output is generated on a daily basis, and therefore is a highly productive by-product of anaerobic digestion.
Biological breakdown To produce biogas, organic matter ferments with the help of bacterial communities. Four stages of fermentation move the organic material from their initial composition into their biogas state. The first stage of the digestion process is the hydrolysis stage. In the hydrolysis stage insoluble organic polymers (such as carbohydrates) are broken down, making it accessible to the next stage of bacteria called acidogenic bacteria. The acideogenic bacteria convert sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. At the third stage the acetogenic bacteria convert the organic acids into acetic acid, hydrogen, ammonia, and carbon dioxide, allowing for the final stage- the methanogens. The methanogens convert these final components into methane and carbon dioxide- which can then be used as a flammable, green energy.
History of biogas This anaerobic process of decomposition (or fermentation) of organic matter happens all around us in nature, and has been happening for a very long time. In fact, the bacteria that break down organic material into biogas are some of the oldest multi-celled organisms on the planet. Human use of biogas, of course doesn’t go thatfar back, however, some anecdotal evidence traces the first uses of biogas to the Assyrians in the 10th century and the Persians in the 16th century. More recently, the 20th century has brought about a renaissance of both industrial and small-scale biogas systems. In the 18th century it became clear to Flemish chemist Jan Baptise van Helmont that decomposing organic matter produced a combustible gas. Soon after, John Dalton and Humphrey Davy clarified that this flammable gas was methane. The first major anaerobic digestion plant dates back to 1859 in Bombay. Not long after, in 1898, the UK used anaerobic digestion to convert sewage into biogas, which was then used to light street lamps. For the next century, anaerobic digestion was primarily used as a means to treat municipal wastewater. When the price of fossil fuels rose in the 1970’s industrial anaerobic digestion plants increased in popularity and efficiency.
LARGE SCALE BIOGAS PLANT
Both India and China began developing small-scale biogas digesters for farmers around the 1960’s. The goal was to decrease energy poverty in rural areas, and make cleaner cooking fuels more accessible in remote areas. Close to one third of the global population still uses firewood and other biomass for energy, causing devastating health and environmental problems. (Link to blog post on developing countries) In India the popular model is known as the floating drum digester, and China’s preferred biogas model is called the fixed dome digester.
FIXED DOME BIOGAS PLANT
Since then, family-sized biogas units are gaining more attention and popularity as both a means of reducing household waste and as a means of providing clean renewable energy to families throughout the world. In the past 15 years, countries around the globe are adopting biogas programs to make both household biogas systems and larger anaerobic digestion plants accessible, efficient, and convenient. As landfills get illegally overloaded, and as the release of methane poses more worrying problems, the benefits of using biogas systems to convert waste into energy are increasingly more relevant and important.
Many Uses of Biogas: Biogas can be produced with various types of organic matter, and therefore there are several types of models for biogas digesters. Some industrial systems are designed to treat: municipal wastewater, industrial wastewater, municipal solid waste, and agricultural waste. Small-scale systems are typically used for digesting animal waste. And newer family-size systems are designed to digest food waste. The resulting biogas can be used in several ways including: gas, electricity, heat, and transportation fuels. For example, in Sweden hundreds of cars and buses run on refined biogas. The biogas in Sweden is produced primarily from sewage treatment plants and landfills.
SWEDISH BIOGAS CAR
Another example of the diversified uses of biogas is the First Milk plant. One of the UK’s biggest cheese makers is building an anaerobic digestion plant that will process dairy residues and convert into bio-methane for the gas grid. New anaerobic digestion plants like these with fascinating stories keep popping up every day!
Small-scale biogas systems Small-scale, or family-size biogas digesters are most frequently found in India and China. However, the demand for such units is growing rapidly throughout the world thanks to more advanced and convenient technologies, The modern world is producing more and more waste, individuals are eager to find ecologic ways to treat their trash.
COMPACT BIOGAS DIGESTER
Traditional systems typically found in India and China focus on animal waste. Due to a lack of energy in rural areas combined with a surplus of animal manure, biogas digesters are very popular, useful, and even life-changing. In many developing countries, biogas digesters are even subsidized and advocated by the government and local ministries, who see the variety of benefits produced from using biogas. In addition to having a clean renewable energy provide gas in the kitchen, many families make extensive use of the fertilizer by-product that biogas digesters provide.
In African countries, some biogas users even turn a profit by selling the bio-slurry by-product produced by biogas systems. This bio-slurry is different from the liquid fertilizer that is produced daily. Bio-slurry refers to the most decomposed stage of the organic matter, after it has been broken down in the system. Bio-slurry sinks to the bottom of the biogas system, and with the help of modern units like HomeBiogas, is easily emptied out once accrued (usually an annual process). This bio-slurry is in fact a nutrient-dense sludge that provides lots of benefits to soil, and can increase productivity of vegetable gardens.
Biogas is a technology that mimics nature’s ability to give back. Both industrial-size and family-size biogas units are becoming incredibly popular and relevant in today’s world. As the application and efficiency grows, biogas can make a significant impact on reducing greenhouse gases. As a clean source of energy and a renewable means of treating organic waste, biogas is applicable both in under-developed and industrialized countries.
Written by: Hilla Benzaken Hilla is a passionate foodie and environmentalist. She writes on energy efficiency, food, and reducing
Biomass—renewable energy from plants and animals
Source: Adapted from The National Energy Education Project (public domain)
Source: Adapted from The National Energy Education Project (public domain) Biomass is organic material that comes from plants and animals, and it is a renewable source of energy. Biomass contains stored energy from the sun. Plants absorb the sun's energy in a process called photosynthesis. When biomass is burned, the chemical energy in biomass is released as heat. Biomass can be burned directly or converted to liquid biofuels or biogas that can be burned as fuels. Examples of biomass and their uses for energy: Wood and wood processing wastes—burned to heat buildings, to produce process heat in industry, and to generate electricity Agricultural crops and waste materials—burned as a fuel or converted to liquid biofuels Food, yard, and wood waste in garbage—burned to generate electricity in power plants or converted to biogas in landfills Animal manure and human sewage—converted to biogas, which can be burned as a fuel
Converting biomass to energy Solid biomass, such as wood and garbage, can be burned directly to produce heat. Biomass can also be converted into a gas called biogasor into liquid biofuels such as ethanol and biodiesel. These fuels can then be burned for energy. Biogas forms when paper, food scraps, and yard waste decompose in landfills, and it can be produced by processing sewage and animal manure in special vessels called digesters. Ethanol is made from crops such as corn and sugar cane that are fermented to produce fuel ethanol for use in vehicles. Biodiesel is produced from vegetable oils and animal fats and can be used in vehicles and as heating oil. How much biomass is used for fuel? Biomass fuels provided about 5% of total primary energy use in the United States in 2017. Of that 5%, about 47% was from biofuels (mainly ethanol), 44% was from wood and wood-derived biomass, and 10% was from the biomass in municipal waste. (Sum of percentages is greater than 100% because of independent rounding) Researchers are trying to develop ways to use more biomass for fuel.
How do we get natural gas?
Writin by https://www.eia.gov/energyexplained/index.php?page=natural_gas_home
How do we get natural gas? Did you know? Because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). This added odor serves as a safety measure to help detect leaks in natural gas pipelines.
Operators preparing a hole for the explosive charges used in seismic exploration
Source: Stock photography (copyrighted) The search for natural gas begins with geologists who study the structure and processes of the earth. They locate the types of rock that are likely to contain natural gas deposits. Some of these areas are on land and some are offshore and deep under the ocean floor. Geologists often use seismic surveys on land and in the ocean to find the right places to drill wells. Seismic surveys on land use echoes from a vibration source at the surface of the earth, usually a vibrating pad under a special type of truck. Geologists can also use small amounts of explosives as a vibration source. Seismic surveys conducted in the ocean rely on blasts of sound that create sonic waves to explore the geology beneath the ocean floor. If a site seems promising, an exploratory well is drilled and tested. Once a formation is proven to be economic for production, one or more production (or development) wells are drilled down into the formation, and natural gas flows up through the wells to the surface. In the United States and a few other countries, natural gas is produced directly from shale and other types of rock formations that contain natural gas in pores within the rock. The rock formation is fractured by forcing water, chemicals, and sand down a well. This releases the natural gas from the rock, and the natural gas flows up the well to the surface. Wells drilled to produce oil may also produce associated natural gas. The natural gas withdrawn from a well is called wet natural gasbecause it usually contains liquid hydrocarbons and nonhydrocarbon gases. Methane and other useful gases are separated from the wet natural gas near the site of the well or at a natural gas processing plant. The processed natural gas is called dry or consumer-gradenatural gas. This natural gas is sent through pipelines to underground storage fields or to distribution companies and then to consumers. Coal may contain coalbed methane, which can be captured when coal is mined. Coalbed methane can be added to natural gas pipelines without any special treatment. Another source of methane is biogas, which forms in landfills and in vessels called digesters. Most of the natural gas consumed in the United States is produced in the United States. Some natural gas is imported from Canada and Mexico in pipelines. A small amount of natural gas is also imported as liquefied natural gas.