SUMMARY: BIO GAS

Biogas is produced when naturally occurring microorganisms breakdown biodegradable material in the presence of the hydrogen gas and in an oxygen-free environment. This process is referred to as anaerobic digestion or fermentation.

Biogas is classified as a renewable energy source, which is recycled naturally.  Furthermore, biogas is carbon-neutral.  It offsets non-renewables such as oil, coal and fossil fuel-derived natural gas.

Biogas is composed of 60-70 percent methane, 30-40 percent carbon dioxide, and trace amounts of other gases.  These gases are captured and transmitted into a combustion device, resulting in the production of energy in the form of direct vehicle gas or high-purity natural gas, biomethane.  There are three types of digesters:  dry batch, continuous, and plug flow.

Biogas is derived from the biological break down of biomass, agricultural manure and slurry, sewage, energy crops, municipal waste, septic tanks, rubbish dumps and green waste.  This natural process takes place anywhere organic matter is produced.

 The easiest way to use biogas is for heating because it requires no pre-treatment, other than the removal of water.  Additionally, it is used to produce vehicle fuel and electricity.  Biogas can also be injected into existing gas networks, such as gas cookers, heaters and baking ovens, to name just a few.  Lastly, industries such as sugar refineries, dairies and paper mills can generate biogas on-site from their processing and wastewater.  Anaerobic digestion technology is widely used in Europe, especially in the UK, where over 66 percent of all sewage sludge was applied in anaerobic digestion.  Although this technology has been present in wastewater treatment plants for almost a century, it has only more recently gained traction as a renewable, more cost competitive-energy source solution to the world’s perpetual reliance on fossil fuels.  Pakistan and India are also avid consumers of biogas. Sweden is one of the leading countries in the area of biogas technology, particularly in the area of vehicle fuel.  More than half of Sweden’s vehicles run on biogas.  

The earth consists of a plethora of un-utilized waste.  These organic residues can be productively and sensibly utilized versus being simply disposed of.  This technology is the ultimate asset for farmers because they can produce their own electricity from their animal manure, while reducing odor pollution, water contamination, and global warming emissions.

Biogas is sustainable because the animals and humans will never stop producing waste. Biogas technology establishes the decentralization of our energy supply, slashes our methane emissions that contribute to global warming, conserves water and grassland, and advances energy independence.  The sustainability of this technology depends on its feedstock and digestate management, which should always be done in closed storage. 

The costs of biogas plants vary significantly and depend on the scale of the operation, whether small or larger scale, or even home-based.  The typical setup cost for a biogas electricity generating plant is $3,700 to 7,000/kilowatt hour with a total energy savings of over $10,000.  The running cost is approximately $0.02/kilowatt hour.  An average shutdown/maintenance and repair period per year is 30 days.  The cost of maintaining a fixed dome biogas plant with or without an expansion chamber is low; on the other hand, a floating gasholder biogas plant is expensive to maintain because the holder must be protected from corrosion.  The typical time for return of investment is 7 years.  This depends on if the biogas is continuously produced and an existing government incentive program is utilized.  On the other hand, an alternative is purchasing at-home portable disgesters, such as Sintex Biogas Plants, which start at $374.  In order to operate one of these plants, all that is required is 25 kg. of cow dung slurry for 1 cubic meter of the plant or approximately 5-6 kg. of kitchen waste.

The social advantages of utilizing biogas include:  improvement in sanitary conditions for the operators and beneficiaries of these plants; the inactivity of pathogens and parasites; reduction in the incidences of water borne illnesses; and lastly, nutritional improvement and famine reduction.  Biogas also makes nighttime activities and the attendance of evening school courses possible in developing nations.  On the contrary, a disadvantage is a poor tenant farmer could be coerced into selling or handing over his manure free of charge to the landlord or higher-earning farmer for use in his or her own biogas plants.  However, this can be remedied in the investment of community biogas systems.  The physical advantages of biogas include:  a smaller, physical footprint versus composting; and the conversion reduces the volume of the waste by up to 60 percent, while the remaining material can compacted into pellets or bricks and sold as solid fuel.  On the other hand, a disadvantage is the costly cleanup of the biogas process.  The technological advantages of utilizing biogas include:  cheaper and much simpler use of technology versus other bio fuels and ideal small-scale application.  However, a disadvantage is that it is especially difficult to increase the efficiency of these systems.   The energy conversion advantages of biogas include:  boundless heat and electrical power production and energy conversion 24 hours a day, 7 days a week.  Lastly, a disadvantage is some plants utilizing energy-intensive techniques, such as plasma, consume more energy than they manufacture.

The environmental benefits of biogas include:  reduction in green house gas emissions; reduction in the potential for contamination of groundwater, surface water, and other resources; destruction of harmful pathogens such as E.coli; and lastly, a decrease in deforestation due to elimination of the need for household charcoal or firewood. Furthermore, there are no environmental concerns at this time.

Biogas continues to attain optimum renewable energy production, while providing the environment with countless other benefits.  Moreover, the world will forever hold a limitless supply of biogas, unlike fossil fuels.  If the United States government invests in incentives and subsidies toward biogas technology, such as other international governments have done in their countries, the need for biogas technology will continue to climb.