
Waste to Energy through Landfill Gasification
This article is a continuation of our series about various topics in renewable energy.
Gasification is the thermal decomposition of organic materials at high temperatures in a limited oxygen environment. The process requires an initial heat supply to produce a combination of combustible gases like methane, hydrocarbons, hydrogen and carbon monoxide. This combination of gases is called ‘syngas’ which can be stored or combusted as it is produced. It is through gasification that biomass to be converted effectively. The most advanced form of gasification can provide for carbon capture which is one way of reducing carbon emissions in successfully combating climate change.
Characteristics of Landfill gas: Landfill gas (LFG) is generated in landfills through the decomposition of organic waste materials normally disposed in landfills. LFG is produced when micro organisms in a landfill break down biodegradable waste like paper and food waste. The main components are methane (50%) and carbon dioxide (48%). It is the methane content makes it a prized fuel source. Methane is a greenhouse gas more than 20 times as powerful as carbon dioxide in trapping heat in the atmosphere. LFG’s composition varies with the age of the landfill, weather conditions, characteristics of the waste and other factors.
Dangers of Landfill gas: LFG is a grave threat to security, to human health and to global warming. It is dangerous for three reasons: (1) LFG becomes explosive when it escapes from the landfill and it mixed with oxygen, (2) It can replace oxygen in the air in closed spaces, enough to case asphyxiation, and (3) LFG is dangerous if the methane level reaches high enough concentrations to cause a fire or an explosion.
Opportunities of Landfill gas: LFG can be an inexpensive resource if local environment regulations necessitate the gas to be extracted and flared away. LFG can help lower the costs of green power when it is combined with solar and wind energy. Electricity from LFG is expected to provide the largest portion of its green power after wind and hydro power.
Utilizing Landfill gas: One way to produce energy from rubbish is to utilize landfill gas. Compressed solid wastes create methane gas. This gas can be trapped, piped to a small plant and combusted to turn a turbine and generate electricity. LFG is a low pollutant fuel with regards to emissions of nitrogen oxides, carbon monoxide, unburned hydro carbons and volatile organic emissions.
Landfill gas process: Landfill gas is fired in a plant’s boilers creating super heated steam. The super heated steam is used to drive the steam turbine or generator to produce electric power. LFG is collected or extracted from landfills by drilling wells into the landfills and collect the gases through pipes. Once the LFG has been processed, it can now be combined with other natural gases to fuel conventional combustion turbines. In the United States, LFG users are one of the top users of renewable energy in the manufacturing industry sector.
Landfill gas opportunities: For many applications, landfill gas can be used as an alternate for natural gas either as a direct source or energy or as a fuel for electric production. Municipalities and other companies have realized the great potential for energy within their reach through the LFG. Landfill trash and garbage generates a naturally occurring gas that can be utilized to displace the conventional fossil fuels.
