How waste-to-energy plants work

Waste-to-energy plants burn municipal solid waste (MSW), often called garbage or trash, to produce steam in a boiler, and the steam is used to power an electric generator turbine.

MSW is a mixture of energy-rich materials such as paper, plastics, yard waste, and products made from wood. For every 100 pounds of MSW in the United States, about 85 pounds can be burned as fuel to generate electricity. Waste-to-energy plants reduce 2,000 pounds of garbage to ash that weighs between 300 pounds and 600 pounds, and they reduce the volume of waste by about 87%.

The most common waste-to-energy system in the United States is the mass-burn system. In this system, unprocessed MSW is burned in a large incinerator with a boiler and a generator to produce electricity. A less common type of system processes MSW to remove noncombustible materials to produce refuse-derived fuel (RDF).

Waste-to-energy plants make steam and electricity

MSW is usually burned at special waste-to-energy plants that use the heat from the fire to make steam for generating electricity or heating buildings. In 2022, 63 U.S. power plants generated about 12.8 billion kilowatthours of electricity from burning about 26.6 million tons of combustible MSW for electricity generation. Biomass materials accounted for about 61% of the weight of the combustible MSW and for about 45% of the electricity generated. The remainder of the combustible MSW was nonbiomass material, mainly plastics. Many large landfills also generate electricity by using the methane gas that is produced from decomposing biomass in landfills.

Waste-to-energy plants are in many countries

Many countries have waste-to-energy plants. The use of waste-to-energy plants in some European countries and in Japan is relatively high, in part, because those countries have little open space for landfills.

Seven-steps process of generation energy in a mass-burn waste-to-energy plant are:

1.Waste is dumped from garbage trucks into a large pit.
2. A giant claw on a crane grabs waste and dumps it into a combustion chamber.
3. The waste (fuel) is burned, releasing heat.
4. The heat turns water into steam in a boiler.
5. The high-pressure steam turns the blades of a turbine generator to produce electricity.
6. An air-pollution control system removes pollutants from the combustion gas before it is released through a smoke stack.
7. Ash is collected from the boiler and the air-pollution control system.

Useable energy can be produced from municipal solid waste

Municipal solid waste (MSW), often called garbage or trash, is used to produce energy at waste-to-energy plants and at landfills in the United States. MSW contains:

• Biomass, or biogenic (plant or animal products), materials such as paper, cardboard, food waste, grass clippings, leaves, wood, and leather products
• Nonbiomass combustible materials such as plastics and other synthetic materials made from petroleum
• Noncombustible materials such as glass and metals

In 2018, about 12% of the 292 million tons of MSW produced in the United States was processed in waste-to-energy plants.

 

Reference: https://www.eia.gov/energyexplained/biomass/waste-to-energy.php

Webmaster: Korn Sanpaudom M.5/4 No.20

Video:

Waste-to-energy is a waste management option

Producing electricity is only one reason to burn MSW. Burning waste also reduces what would probably be buried in landfills.

Waste-to-energy plants reduce 2,000 pounds of garbage to ash that weighs about 300 pounds to 600 pounds, and they reduce the volume of waste by about 87%