Energy/Waste FAQ
Answers to Frequently Asked Questions Regarding Waste-to-Energy
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What is the cost to a community to develop and build a WTE facility?
- What is the expected generation of electrical energy?
- What are the costs to operate the facility after it is complete?
- What are the economic benefits?
- What is the amount of ash and/or vitrified glass generated?
- What are the environmental benefits of using WTE instead of land-filling?
- What is the amount of MSW generated by the average U.S. citizen and how much of it is suitable for combustion?
- What is the minimum amount of solid waste that is needed for a WTE plant?
- What are the preliminary requirements and steps that must be taken, negotiations to be completed, contracts to be signed before a facility can be built?
- Where are WTE facilities located?
- Most WTE facilities located in the United States accept and dispose of waste that is generated by commercial sources that is non-hazardous… how are the Integra WTE facilities different?
- How do WTE emissions compare with those from other types of plants that generate energy? What types and quantities of emissions do WTE facilities discharge into the air, water or land? How do typical WTE emissions compare with typical landfill emissions per ton of MSW?
- How frequently are new WTE plants built, and where?
- What are the constituents of ash?
- Can WTE ash and/or vitrified glass be used for anything useful?
- What happens to ash that is not used?
- What environmental laws and regulations must be followed by WTE plants? Are there separate rules issued by the federal government and states?
- What are the different WTE technologies?
- Is recycling compatible with use of WTE facilities in a community?
- Why can't New York City recycle the same as San Francisco who are said to recycle 60% of their MSW?
- What is the cost to a community to develop and build a WTE facility?
Depending on the location, size, and other factors, the capital costs range from $200,000 to 295,000 per daily ton of capacity. Therefore, a plant that processes 1,000 tons of Municipal Solid Wastes (MSW) per day that produces 60 mWh may cost $295 million.
- What is the expected generation of electrical energy?
An Integra WTE plant using processed MSW will generate a net of 1,200-1,400 kWh per ton for use by the local utility. At the price of eight cents per kWh, the revenues per ton of processed MSW would be $96-$112.
- What are the costs to operate the facility after it is complete?
In addition to the capital charges, a 1000-ton per day plant would engage personnel of about 60, plus other costs such as services, materials, supplies and the cost of disposal of un-reusable ash would be approximately 15-20%.
- What are the economic benefits?
- The value of the electrical energy generated.
- The “tipping” fees paid by the communities using the WTE facility.
- The value of the ferrous and non-ferrous scrap collected.
- Cost of land-fill space is less or eliminated altogether.
- Valuable land reclaimed for other purposes if the land-fill site is mined and cleaned up.
- What is the amount of ash and/or vitrified glass generated?
It ranges from 15-25% by weight of the MSW processed and from 5-15% of the volume of the MSW processed.
- What are the environmental benefits of using WTE instead of land-filling?
- WTE plants conserve fossil fuels by generating electricity. One ton of MSW combusted reduces oil use by one barrel (i.e., 35gallons) or 0.25 tons of coal.
- It has been estimated that one ton of MSW combusted rather than land-filled reduces greenhouse gas emissions by 1.5 tons of carbon dioxide.
- WTE plants do not have the aqueous emissions that may be experienced in landfills, either now or in the distant future.
- WTE plants reduce the space required for land-filling by about 90%.
- What is the amount of MSW generated by the average U.S. citizen and how much of it is suitable for combustion?
Americans generate about 1.31 short tons of MSW per person, each year. The 2002 Bio- Cycle/Columbia University national survey showed that Americans recycle about 19.5% of the MSW generated, compost an additional 9%, combust in WTE facilities 8% and landfill about 63%. The Earth Engineering Center of Columbia University has estimated that of the present MSW generated in the U.S., at the most 40% can be recycled or composted. Therefore, the maximum possible MSW available for combustion in modern WTE facilities will be 60%, instead of the present 8%.
- What is the minimum amount of solid waste that is needed for a WTE plant?
There are economies of scale in any construction project, and building a WTE plant is no exception. Larger plants result in lower costs per ton of MSW processed. In the U.S., most WTE facilities range from 500 to 3,000 tons per day. Integra WTE plants are scalable from 1,000 tons per day to 5,000 tons per day of processed characterized MSW.
- What are the preliminary requirements and steps that must be taken, negotiations to be completed, contracts to be signed before a facility can be built?
An Integra WTE facility requires a site, first and foremost, that is properly zoned and near major roads, highways, a utility substation, and has water, sewage and an appropriate industrial infrastructure. Twenty-five acres is preferred, but some facilities are located on as little as 5 acres if trucks can line up off site. Before construction can begin, a projects needs to secure the following:
- Waste characterization in terms of composition, heating content, moisture, etc.
- Site control through lease or ownership.
- Proper zoning and/or land use conformance.
- Environmental permits.
- Utility interconnections.
- Power purchase agreement including off-take guarantees.
- Materials purchase agreements.
- Ash disposal (landfill) capacity if necessary.
- Waste supply commitments to ensure future viability.
- Acceptable credit worthiness of all project participants including the government, bank utility or other entity require to make financial guarantees.
- Guarantees including governmental entities at the federal, state, and local levels.
- Current cost of waste disposal.
- Availability and cost of disposal alternatives.
- Once the site and all contracts are secured, the facility may be financed and construction can begin. The construction period lasts approximately 18-24 months.
- Where are WTE facilities located?
In the U.S., there are 102 WTE facilities located in 29 states. For a detailed list, look up www.wte.org
- Most WTE facilities located in the United States accept and dispose of waste that is generated by commercial sources that is non-hazardous… how are the Integra WTE facilities different?
Most WTE facilities combust special, non-hazardous wastes such as off-specification household products and goods that cannot be recycled. However, Integra’s WTE pyrolysis process is designed and US-EPA approved to safely dispose of even the most hazardous materials known to man, therefore there are no limitations as to what can or cannot be disposed of through the system process.
- How do WTE emissions compare with those from other types of plants that generate energy? What types and quantities of emissions do WTE facilities discharge into the air, water or land? How do typical WTE emissions compare with typical landfill emissions per ton of MSW?
 The WTE industry recent the EPA’s New Clean Air Act “Maximum Control Technology” (MACT) standards. In a 2002 letter, U.S.E.P.A. Assistant Administrators Jeffery Holmstead, Office of Air and Radiation, and Marianne Lamont Horinkontly completed a more than $1 billion retrofit to existing facilities, the Office of Solid Waste and Emergency Response, recognized the “vital role of the nation’s municipal waste-to-energy industry” and concluded that “these plants produce 2800 megawatts of electricity with less environmental impact than almost any other source of electricity.” The Table below shows the dioxin/furan TEQ emissions in the U.S. from various sources that also include WTEs. The following figure compares mercury emissions from WTEs and coal-fired power plants in the U.S.
- How frequently are new WTE plants built, and where?
In the U.S., most of today’s operating WTE plants were built in the period of 1980-1995. Energy prices and landfill disposal costs dropped in the mid-1990’s making WTE plants more difficult to develop. However, new WTE units are under development in several states including Florida, Hawaii, Massachusetts, Pennsylvania, and Minnesota. Crowded urban areas and locations where groundwater is close to the surface benefit most from WTE facilities. Abroad, there have been over 60 new WTE plants built since 1996 and some are under construction. In all there are over 600 WTE plants in the world located in 37 nations, including Bermuda, Singapore and China.
- What are the constituents of ash?
Generally, WTE residues can be differentiated into two fractions: The term fly ash refers to the fine particles that are removed from the flue gas. However, usually the fly ash includes also residues from other air pollution control devices, such as scrubbers. Fly ash typically amounts to 5-10% by weight of the total ash. The rest of the WTE ash is called bottom ash and/or vitrified glass which is about10% by weight of the total ash. The chemical composition of the ash depends strongly on the original MSW feedstock and the combustion process.
- Can WTE ash and/or vitrified glass be used for anything useful?
WTE ash and/or vitrified glass has been reused in construction since the early 70’s. Common applications are sub-base material, structural fill, and aggregate in asphalt or concrete. However, in the past, contaminant concentrations of fly ash exceeded the allowable threshold values. Ash reuse is therefore restricted to proven processes. Because there are no nationwide standards in the U.S. less than 5% of the WTE ash is beneficially used (compared to bottom ash reuse of ~70% in Germany and ~90% in the Netherlands). The government of Bermuda uses the entire WTE ash in concrete products for artificial reefs or shore abatements. The Waste-to-Energy Research and Technology Council is therefore taking an innovative approach towards our understanding and beneficial use of ash. An interdisciplinary and inter-institutional research group will carry out a comprehensive project on reuse applications such as engineered aggregate, cement blocks, asphalt, remediation of brown-fields and abandoned mines, and concrete. One of the main goals is to recommend authoritative, nationwide standard specifications.
- What happens to ash that is not used?
Ashes that cannot be reused are land-filled. Usually, combined WTE ashes do not qualify for unrestricted disposal but are placed in mono-fills while it is easier to place bottom ash alone because it rarely exceeds the maximum permitted concentrations for land-filling.
- What environmental laws and regulations must be followed by WTE plants? Are there separate rules issued by the federal government and states?
In the USA, WTE facilities are primarily regulated under the federal Clean Air Act and the Resource Conservation and Recovery Act. The Clean Air Act requires plants to obtain permits whose provisions are based on plant size and technology. Federal and state regulators enforce emissions limits for sulfur dioxide, hydrogen chloride, nitrogen oxides, carbon monoxide, particulates, cadmium, lead, mercury, and dioxins. Operating conditions, monitoring, reporting, training and safety requirements also apply under the Clean Air Act. The Resource Conservation and Recovery Act require testing of the plants’ ash residue to determine that the ash is non-hazardous and properly disposed or reused. States often take authority for enforcement of the regulations and require even stricter environmental limits on the facilities’ operation than imposed by the federal rules. State-specific requirements can include more strict emission limits, testing or reporting than federal rules; additional solid waste management, recycling, noise, site selection, transportation and related regulations; and water use or waste water management limits.
- What are the different WTE technologies?
The predominant technology is mass burning and the foremost process used is that developed by Martin (Munich, Germany) with installed annual capacity of about 59 million metric tons. The Von Roll (Zurich, Switzerland) mass burning process follows with 32 million tons worldwide. Other mass burning technologies are the roller grate (DB) and the Westinghouse process. There are several plants in the U.S. based on the Refuse-Derived Fuel (RDF) process that pre-shreds the waste into small pieces and separates some of the non-combustible materials (metals and glass). And Integra is one of the only companies in the world positioned to deploy proven US-EPA approved Rotary Kiln pyrolysis technology that can destroy 307 most toxic waste materials with a DRE (Destruction Removal Efficiency) of 99.99999% with ash and steam as the only remaining byproducts.
- Is recycling compatible with use of WTE facilities in a community?
As a rule, the communities that invest in WTE plants, because of the energy and environmental benefits described above, also do as much as possible recycling before sending the non-recyclable waste to their WTE. Despite all good intentions and efforts some waste materials are not recyclable economically in the U.S. because of the comparatively low cost of fossil fuels. For example, out of the 25 million tons of plastics generated annually in the U.S., only 1.5 million tons are recycled, 3.5 million are combusted and 20 million tons are land-filled, despite the fact that their heating value is higher than the best U.S. coal.
- Why can't New York City recycle the same as San Francisco who are said to recycle 60% of their MSW?
It is easy to juggle % recycling rates but the real evidence of sound waste management is provided by how many tons of MSW a city landfills. The official SF web page, SFgov.org, reports that SF generates 4,000 tons MSW per day of which 60% is land- filled. Therefore, SF citizens (population 760,000) landfill 0.96 tons per capita which is slightly higher than the California average of 0.9 tons and nearly the same as NYC. Tourist destinations usually generate more MSW per capita.
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