"WtE" Projects
Waste to Energy
The Clean Truth:
For every ton of municipal solid waste processed at waste-to-energy (WtE) facilities, greenhouse gas emissions are reduced by approximately one ton. WtE plants provide a safe waste disposal option that complements (not replaces) recycling. Recycling rates have actually increased in municipalities that have WtE plants. WtE Technology supports business and industry "Zero-Waste-to-Landfill" initiatives.
Most waste ends in landfills. Rather than future generations facing the impacts of a traditional, linear economy — WtE Technology is helping our planet transition to a Circular Economy where energy is recycled in a loop and waste becomes a resource in and of itself.
Waste-to-energy power plants are an integrated part of this model.
Waste is burned at high temperatures to destroy chemicals, heat is transformed into energy and steam drives a turbine that creates clean electricity. Most importantly — the waste is diverted from the landfill and enters “the loop,” while we recover clean water, metals and other materials.
What is Waste-to-Energy?
Ecologically Sound, Cost-Effective Energy
Waste-to-energy (WtE), also known as energy-from waste (EfW), is a vital part of a strong and sustainable waste management chain. Fully complementary to recycling, it is an economically and ecologically sound way to provide a renewable source for energy while diverting waste from landfills.
A WtE plant converts solid waste into electricity and/or heat - an ecological, cost-effective way of energy recovery.
A waste-to-energy plant converts municipal and industrial solid waste into electricity and/or heat for industrial processing and for district heating systems – an ecologically sound, cost-effective means of energy recovery. The energy plant works by burning waste at high temperatures and using the heat to make steam. The steam then drives a turbine that creates electricity.
Recover valuable resources
Harnessing energy from waste isn’t just a trash disposal method. It’s a way to recover valuable resources. Today, it is possible to reuse 90% of the metals contained in the bottom ash. And the remaining clinker can be reused as road material.
The results and benefits are proven:
Avoids methane emissions from landfills
Offsets greenhouse gas (GHG) emissions from fossil fuel electrical production
Recovers/recycles valuable resources, such as metals
Produces clean, reliable base-loaded energy and steam
Uses less land per megawatt than other renewable energy sources
Sustainable and steady renewable fuel source (compared to wind and solar)
Destroys chemical waste / conventional HAPs
Results in low emission levels, typically well below permitted levels
Catalytically destroys NOx, dioxins and furans using an SCR
High efficiency and low emissions
Waste to energy is one of the most robust and effective alternative energy options to reduce CO2 emissions and replace fossil fuels. Approximately 2/3 of household waste is categorized as biomass. Therefore, we can recover 2/3 as CO2-neutral energy and reduce our dependence on fossil fuels.
In Europe, 50 million tons of waste is converted into valuable energy through EfW technology, supplying 27 million Europeans with electricity. Still, 50% of municipal solid waste becomes landfill. This releases greenhouse gasses like methane. Our energy from waste technology eliminates these emissions.
Our goals are two-fold: to maximize production and efficiency to meet energy needs, and to reduce our environmental footprint.
Waste facts
4 tons of waste equals 1 ton of oil
2 tons of waste equals 1 ton of coal
Source: B&W
Amager Bakke / Copenhill Case Study
B&W scope
Crane
Feeding system with hopper
Boiler
Ash system
Electrical system
Electrostatic precipitator (ESP) for the reduction of particles in the flue gas
Selective catalytic reduction (SCR) for reduction of NOx emissions
Economizer for flue gas cooling
Combustion control system
Copenhagen’s state-of-the-art Amager Bakke sets new standards for environmental performance, energy efficiency and waste treatment capacity.
Just across the bay from the queen’s palace, it includes a roof-top ski slope and a hiking trail, with trees growing on landscaped sections. The plant was constructed by Amager Ressourcecenter, owned by five Copenhagen municipalities.
Amager Bakke is equipped with two furnace lines and a joint turbine and generator system. Each line burns 35 tonnes of waste per hour and is designed to:
Treat approximately 400,000 tonnes of waste annually produced by 600,000 inhabitants and at least 46,000 companies
Supply a minimum of 50,000 households with electricity and 120,000 households with district heating
Supply 440 °C steam at 70 bar, which doubles the electrical efficiency compared to the former plant
Emit much lower emissions than the EU’s stringent 2019 Best Available Techniques Reference Document for Waste Incineration
A DynaGrate® at Heart
Water-cooled dynamics make the difference
The innovative technology of the DynaGrate combustion grate is unique in its fuel flexibility, optimized combustion and minimal maintenance cost, all due to the mechanical design and optimized water-cooling system. The entire cooling system is well integrated and protected in the steel shaft. Also, movable grate parts are not in contact, thereby reducing grate wear.
Further, the mechanical break-up of the waste layer on the grate results in thorough agitation and superior combustion conditions. The watercooling system allows high heating values that are vital to fuel flexibility. Together, the water-cooling and mechanics result in high plant efficiency and excellent burnout of the waste, as evident from very low TOC values (around 0.2%) in bottom ash.
Optimized combustion
Since the water-cooled DynaGrate system is not dependent on air cooling, full control of the primary combustion air is achieved. This optimizes the combustion process to reduce NOx formation at the source. B&W Vølund tests operating at oxygen levels around 4.5 – 5% show NOx levels in the range of 200 – 250 mg/Nm3. This is before the flue gas reaches the SCR filter.
Moreover, low excess air results in less flue gases, thereby reducing the stack loss and fan power consumption. In addition to low NOx emissions, our VoluMix™ overfire air system, designed using computational fluid dynamics (CFD), reduces CO and TOC to a minimum. The Volumix process injects secondary air into the combustion zone, with a complete burnout in the gas phase.
* All values refer to 11% O2 dry gas
** 24-hour average
*** Half-hour average
US - Information - Waste-to-energy (Municipal Solid Waste)
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.
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 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%.
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.
Last updated: November 6, 2023, with data available at the time of update.
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).
A mass-burn waste-to-energy plant
Source: Adapted with permission from Deltaway EnergyGenerating electricity in a mass-burn waste-to-energy plant is a seven-step process:
Waste is dumped from garbage trucks into a large pit.
A giant claw on a crane grabs waste and dumps it into a combustion chamber.
The waste (fuel) is burned, releasing heat.
The heat turns water into steam in a boiler.
The high-pressure steam turns the blades of a turbine generator to produce electricity.
An air-pollution control system removes pollutants from the combustion gas before it is released through a smoke stack.
Ash is collected from the boiler and the air-pollution control system.
Last updated: December 21, 2023.
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B&W is Part of ISWA EfW Technologies Publication
As a member of the International Solid Waste Association (ISWA), B&W is proud to be part of ISWA’s White Book on Energy-from-Waste Technologies, a publication which provides a comprehensive overview of the technical, economic, legislative, institutional, social, and environmental aspects of the available thermal technologies which produce energy from waste (EfW). We were part of the working group that produced this publication and directly contributed to its development.
