5 Waste to Energy Examples Explained
Waste to energy examples are; waste combustion, transport fuel production, waste-based cogeneration, cooking gas production, and waste-based power generation.
This article discusses the waste to energy examples as follows;
1). Waste Combustion (as one of the Waste to Energy Examples)
Waste combustion is the burning of waste materials, with the release of energy in form of heat. It is one of the most simple and common waste to energy examples.
Burning of waste; or incineration, is an alternative method of waste management, to other methods like landfilling . Unlike landfilling, it is also a more recommendable option for sustainable development and circular economy.
This is because waste combustion produces energy that can be used for various purposes. Such energy can be viewed as some form of renewable energy, since waste production is a renewable process.
However, waste combustion is only recommendable when practiced in a manner that ensures sustainability. This includes making efforts to recover heat effectively, minimizing emissions and environmental degradation, and conserving combustion residue.
A poor approach to waste combustion will increase the severity of environmental problems like air quality decline, global warming and greenhouse emissions .
Waste combustion has been described as an energy efficient method of waste management . The energy efficiency of this method is based on the fact that up to 80% of energy used during waste combustion is not lost.
After heat energy has been released from waste through combustion, this heat can be used for different purposes. For example, the heat can be used to produce steam which is used to drive a turbine-based electric generator, in order to generate electricity. It can also be used for cooking and space heating.
The residue from waste combustion may be referred to as; ‘char’ or ‘biochar’, and is usable for soil conservation and enrichment, as part of sustainable farming .
It is important to note that all cases of waste burning involve waste-to-energy conversion, since the waste material is being decomposed by high temperature to release heat.
2). Waste-based Cogeneration
Cogeneration is the simultaneous production of heat and electricity .
It is listed among the waste to energy examples,, to indicate that waste can be used to produce both heat and power, simultaneously.
The goal of cogeneration in waste-to-energy conversion, is energy conservation. Here, effort is made to minimize energy loss in the form of waste heat. Such heat is used for an alternative purpose, like domestic water-heating.
This approach is mostly used where heat energy from waste is being used for electricity generation. It ensures that the process is sustainable, by conserving heat and reducing wastage.
For large-scale operations, a cogeneration power plant is usually required, because it is suitably equipped to capture and utilize waste heat .
3). Transport Fuel Production (as one of the Waste to Energy Examples)
Waste materials can be converted to fuels that are useful in transport .
Such fuels are mostly biofuels that are produced when organic waste is made to undergo reactions that alter the physicochemical properties of this waste.
The concept of waste to energy for transport fuel production, is similar to other concepts like electric car development, hybrid cars, liquid hydrogen and hydrogen fuel cells. This is because it aims to provide a renewable source of power for automobiles.
Transport fuel can be produced from biodegradable waste. This waste may be in the form of agricultural waste, municipal solid waste, or industrial waste.
Before the waste can be used, it has to be sorted or segregated to ensure that organic materials are separated from inorganic materials.
Organic waste is a form of biomass. To produce transport fuel from such waste, various biomass conversion methods can be used.
A common example of such methods is fermentation . This method can be used to convert waste material to bioethanol, which is usable as a transport fuel. Other methods like pyrolysis are also usable.
4). Cooking Gas Production (as one of the Waste to Energy Examples)
Waste materials can also be converted to cooking gas.
This gas is alternatively referred to as biogas, syngas or biomethane, and is a byproduct of the thermal or biochemical breakdown of organic matter .
Biogas can be produced in large scale in a biorefinery, or any other waste-to-energy facility. A common and effective method for producing this gas is anaerobic digestion, which combines biochemical reactions with thermal processes to alter the composition and physicochemical characteristics of organic matter, under controlled conditions in a digester or reactor.
Sewage is a form of waste that can be used to produce biogas . Others include kitchen waste and agricultural waste.
5). Waste-based Power Generation
The concept of waste-based power generation refers to the use of energy from waste to generate electricity.
To achieve this, it is often necessary to carry out waste combustion.
Here, the waste is burnt as fuel to release heat energy, which is subsequently converted to electricity .
The electricity produced from waste as outlined above, can be considered similar to other renewable types of electricity like hydroelectricity and photoelectricity, since it is derived from renewable biomass.
Waste to energy examples are;
- Waste Combustion
- Waste-based Cogeneration
- Transport Fuel Production
- Cooking Gas Production
- Waste-based Power Generation
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