Because the EfW process is irreversible, the decision to reprocess urban wastes for the primary purpose of energy recovery has implications for sustainable resource use. On the one hand, the recovery of the calorific value of the waste and its corresponding benefits may be preferable to losing the potential for energy recovery to landfill disposal. On the other hand, the irreversible consumption of a resource for energy alone may not fully acknowledge the more sustainable resource use of that material, by reuse, recycling or reprocessing for the inherent material recovery and the greater embodied energy value.

Such resource decisions are of vital interest to the broader community as we consider our collective responsibility to future generations. This highlights the need for community consent for projects that seek to recover energy value from urban waste. In order to gain this consent it is important for the potential impacts, both positive and negative, to be properly identified and understood in order to determine the suitability of an EfW project.

The Potential Impacts of Energy Recovery from Urban Wastes

The benefits of energy recovery from urban wastes can include the following:1) a higher value resource management outcome than to lose the same materials through landfill

disposal2) the biomass or lignocellulosic content of urban wastes can present as a renewable source of

energy3) the hydrocarbon-based content (high calorific plastic-, textile- and fossil-fuel-based fraction) of

urban wastes can present as a source of alternative or supplementary energy4) use of certain urban wastes for energy recovery can deliver a reduced greenhouse gas impact

when compared to directly applied fossil fuels or the landfill alternative where organic material is not collected separately and diverted

5) a reduction in volume of the solid waste that is consigned to landfill6) appropriate conversion of certain urban wastes for energy recovery close to the potential

markets for this energy can demonstrate significant transport and transmission advantages7) processing urban wastes for energy recovery can demonstrate significant public health, hygiene

and public amenity advantages over many alternative applications such as landfill disposal.

Like any waste management option, inappropriate energy recovery from urban wastes can produce significant disadvantages such as:

1) wasted resource value from a once-off application for energy from materials that had ongoing or higher resource value applications available

2) direct impacts of polluting emissions (including health impacts), odours, dust and noise3) maintaining a demand for the creation of waste, rather than avoiding waste, simply to satisfy

the needs of the EfW facility.

An objective of sustainable development is to ensure optimum benefits within a framework that eliminates or minimises the potential disadvantages.

Key Stakeholder GroupsThere is a wide range of individual stakeholder and special interest groups with whom consultation is an important factor in gaining acceptance and approval for a development. These groups can be loosely categorised as community, government and industry and encompass the following stakeholders:

1. communitya) neighbouring residents, workers, businesses and sensitive landuses such as schools, community

centres and aged care facilitiesb) the electorate (local, state, federal)c) environmental NGOsd) special interest groups

2. governmenta) local governmentb) state governments and their individual agenciesc) federal government and its individual agencies

3. industrya) project developers and proponentsb) waste generators, suppliers and collectorsc) technology developers and vendorsd) energy wholesalers and retailers

Ecologically Sustainable Development (ESD) as the Primary DeterminantThe management of urban wastes is an issue that goes to the heart of the social, environmental and commercial debate over the impact modern civilisation is having on the biosphere and its natural systems. The definition of ecologically sustainable development (ESD) adopted in this strategy is:A pattern of development that improves the total quality of life both now and in the future, in a way that maintains the ecological processes on which life depends.

Society’s resources are to be managed in a way that improves our quality of life today without compromising the ability of future generations to improve their own quality of life.

This concept of sustainability accepts that all human and natural activity has an impact, but advocates that the biosphere must be capable of sustaining or absorbing these impacts. Human activity that causes impacts which natural systems cannot repair is unsustainable.

The term “waste to energy” has traditionally referred to the practice of incineration of garbage. Today, a new generation of waste-to-energy technologies is emerging which hold the potential to create renewable energy from waste matter, including municipal solid waste, industrial waste, agricultural waste, and waste byproducts. The main categories of waste-to-energy technologies are physical

technologies, which process waste to make it more useful as fuel; thermal technologies, which can yield heat, fuel oil, or syngas from both organic and inorganic wastes; and biological technologies, in which bacterial fermentation is used to digest organic wastes to yield fuel.

Waste-to-energy technologies can address two sets of environmental issues at one stroke – land use and pollution from landfills, and the well-know environmental perils of fossil fuels.

Waste-to-energy technologies convert waste matter into various forms of fuel that can be used to supply energy. Waste feedstocks can include municipal solid waste (MSW); construction and demolition (C&D) debris; agricultural waste, such as crop silage and livestock manure; industrial waste from coal mining, lumber mills, or other facilities; and even the gases that are naturally produced within landfills. Energy can be derived from waste that has been treated and pressed into solid fuel, waste that has been converted into biogas or syngas, or heat and steam from waste that has been incinerated. Waste-to-energy technologies that produce fuels are referred to as waste-to-fuel technologies.Advanced waste-to-energy technologies can be used to produce biogas (methane and carbon dioxide), syngas (hydrogen and carbon monoxide), liquid biofuels (ethanol and biodiesel), or pure hydrogen; these fuels can then be converted into electricity. The primary categories of technology used for waste-to-energy conversion are physical methods, thermal methods, and biological methods.

Today’s waste-to-energy (WE) electric power plants are far removed from the low-tech burners of yesterday. Rugged marvels of engineering, they can be tailored to burn anything from industrial, agricultural, and lumber by-products, to the waste we generate in our homes, to ancient waste buried in landfills decades old. Modem WTE plants have been well analyzed for environmental impact. They are equipped with the latest in combustion and pollution control technologies to keep emissions and toxins not only below those that increase risks to public health, but below those detectable by the most sensitive tests in use. Waste combustion provides integrated solutions to the problems of the modem era: by recovering otherwise lost energy and metals, thereby reducing our use of precious natural resources; by cutting down our emissions of greenhouse gases; and by both saving valuable land that would otherwise be destined to become landfill and recovering land once sacrificed to the products of consumerism.

Waste-to-energy provides the fourth “R” in a comprehensive solid waste management program: reduction, reuse, recycling, and energy recovery.

The benefits of full-scale implementation of energy recovery as a final step in waste management are evident: conservation of natural resources and fossil fuels, drastic landfill reduction, and lower greenhouse emissions.

The need for an integrated solid waste management strategy in a city, state, or country becomes more evident as that region’s economy grows and the standard of living improves. With increases in consumption, the amount of waste generated also increases. This creates stresses on the land used for

disposal, can lead to environmental pollution, and can be detrimental to public health if the waste is not disposed properly.

From an integrated solid waste management standpoint, waste-to-energy can be an effective solution to India’s waste crisis for the following reasons

Waste-to-energy is a renewable technology. It prevents the emission of greenhouse gases (GHG) from landfills, displaces fossil fuels used for power generation by creating energy from the combustion of MSW, and is an environmentally superior form of waste disposal as compared to landfills.

Economic growth increases the amount of goods that are consumed, thus increasing the amount of waste generated. A strategy of whether this waste will be recycled or incinerated or landfilled needs to be developed, keeping in mind economic, social, and environmental costs and benefits.

When urban areas begin to develop the space available for dumping or landfilling waste becomes scarce as the need for housing, schools, parks, and overall urban development becomes a priority. WTE provides an effective way to reduce the volume of waste by approximately 90% and thereby lower the space needed for landfills.

The consumption of plastics is expected to increase sharply in the future. To the extent possible, plastics should be recycled; however, not all forms of plastic are suitable for recycling. In this case, waste-to-energy is preferable to landfilling since plastics have a high heating value.

Waste-to-energy is not only a solution to reduce the volume of waste that is and provide a supplemental energy source, but also yields a number of social benefits that cannot easily be quantified.

As the environmental issues concerning waste management have evolved, and the concept of a waste hierarchy has developed, it has become clear that an increasingly important reason to incorporate an EfW component within an integrated waste strategy is for the recovery of energy from the residual waste stream.

The argument that energy recovery is not compatible with high levels of recycling and composting is confounded by the experiences of other countries. The available waste streams and markets for materials recovered from them are able to accommodate high levels of recycling/composting alongside energy recovery. Furthermore, the perception that thermal treatment of the post recycling waste stream will be compromised by the resultant ‘low calorific value’ of the residual waste available for the process and, hence, the validity of this as an option, is also contradicted, by research into calorific values of different waste streams.

The technology of EfW plant (as described in subsequent chapters) has been demonstrated to be flexible, proven and robust enough to operate on varied feedstocks to different scales and can therefore be designed to be of appropriate size as a component of an integrated solution.

Integrating Energy from Waste into the community and the environment

There are many examples of good practice overseas and in the UK regarding the integration of EfW plant into the community. These show that plants can be designed to accommodate the needs of a particular town or community and can then provide lower cost district heating to that same community (as well as electricity) thus ‘closing the loop’ and utilising the residual waste emanating from a locality in a positive and beneficial manner. Additionally, facilities are now being designed in a variety of imaginative ways to make a positive contribution to the environment. In Vienna, one of its EfW plants is an architectural feature of the city. In many other European cities, EfW is integrated into the district heating infrastructure. For example, Paris has three large EfW facilities with extensive district heating systems on the Peripherique, which supply around one third of central Paris’ heat requirement.

There are several drivers for exploring the environmental benefits of using waste as a source of energy, fuels, or chemicals for further processing and manufacturing of products:

First, it is critical to significantly reduce greenhouse gas (GHG) emissions from every practice and technology in all sectors and consumer behaviors. Depending on the scenario, using wastes as sources of energy may have a favorable GHG profile, compared to conventional energy sources.

Second, consumers and industries strive to increase the availability and reduce the cost of energy for electricity, transportation fuels, and heating. Additionally, our increased demand for primary energy has led to the degradation of natural resources (e.g., water and land) and ecosystems, and generation of significant amounts of solid waste, water and air pollution.

Third, in a world with high prices for dwindling material resources, it is increasingly desirable to derive the highest value for discarded materials, and use them in ways that extend their lifetime use and encourage reuse. This resource conservation is critical for environmental, economic, and resource sustainability.

Fourth, waste generation per capita has increased and is expected to continue to climb with growing population, wealth, and consumerism throughout the world. Communities are challenged to develop systems for managing discarded materials that are cost-effective, have minimal impact on air, water and soil.

These four trends, combined, present both challenges and opportunities. Converting wastes to energy products hold the promise of: 1) providing more sustainable waste management options

2) providing alternative energy solutions

3) providing increased value of discarded materials

4) decreased environmental and GHG impacts

5) reducing dependence on foreign energy sources and increasing national security

6) development of technologies that aid in transitioning to a hydrogen economy

7) introduction of technologies that can respond to future legislation constraining carbon dioxide emissions

8) enhancing rural power production