Economic, Environmental, and Sociopolitical Aspects of Waste Incineration: A Scoping Review

Abstract

Objective: To examine the economic, environmental, and sociopolitical aspects of waste-to-energy incineration (WtE-I) and to provide recommendations for the Australian context. Methods: A scoping review of the literature published from 2016 to 2024 was conducted, adhering to the PRISMA guidelines. Results: This review identifies WtE-I as a dual-purpose tool for energy production and waste management. However, its environmental profile is unclear, with potential significant environmental and health risks due to the emission of toxins and heavy metals and diminished air quality. The economic feasibility of WtE-I varies, with high initial costs and operational expenses offset by subsidies, revenue from energy, and material recovery. Public opposition to WtE-I is prevalent, driven by health concerns, and this raises important environmental justice issues, especially for marginalised communities. Conclusions: The present study provides economic, environmental, and sociopolitical recommendations against WtE-I. When compared to landfill, WtE-I demonstrates economic and environmental benefits. The transition to a circular economy with renewables-derived electricity attenuates the benefits of WtE-I. This, combined with grassroots opposition to WtE-I and its violations of social justice, renders future WtE-I projects unjustifiable. Public health practitioners need to promote primary waste reduction, recycling/composting, and other non-incinerator waste management practices in Australia.

1. Introduction

Currently, parallel demands for renewable energy and waste disposal make waste-to-energy incineration (WtE-I) an attractive solution for governments. By liberating energy from municipal waste, WtE-I can generate electricity, sanitise hazardous materials, and reduce reliance on landfill [1,2]. WtE technologies include direct combustion (incineration), pyrolysis, and gasification [3,4,5]. This study focused on WtE-I for two reasons; firstly, because pyrolysis and gasification are only emerging technologies in the Australian context, and secondly, to limit the scope of the study to resource capacity. In WtE incineration (WtE-I), heat energy from waste combustion produces steam that drives turbines to generate electricity or heat for municipal heating systems [6,7,8]. Economically valuable materials can be recovered from the solid residue left behind after incineration [9].

WtE-I has helped policy-makers consolidate energy supply and drive economic outcomes [1,10,11] and manage the environmental impacts of traditional waste management [12]. WtE-I can reduce waste volume compared to landfills and may lower greenhouse gas emissions (GHG) by avoiding landfill and reducing reliance on fossil fuels [6], thereby positively impacting climate change and its public health consequences [13].

The benefits of WtE-I are particularly impactful for developing nations where burning waste for electricity can stabilise the electricity grid and stimulate economic development [14], which can, in turn, drive greater health outcomes—although a clean energy source is preferred [15]. Consequently, WtE-I is increasingly being integrated into regulatory frameworks [6,8]. Strategic policy is shifting from waste minimisation towards a mixed strategy that includes energy recovery from waste using WtE-I under allegedly strict environmental regulations [16].

Municipal solid waste (MSW) is a major fuel source for WtE-I. MSW is a very heterogenous fuel source and comprises organics (food and garden waste), recyclables (paper, plastics, metals, and glass), and other materials (rubber, textiles, construction debris), distinct from industrial solid waste (ISW). The annual global generation of MSW is increasing and is expected to reach 2.2 billion tons by 2025 [17]. WtE-I is proposed as a sustainable energy source to manage this increase, but its status as a ‘clean’ energy source depends on the MSW composition and WtE-I plant technology, including adequate GHG capture and reduction in noxious emissions [18].

There are concerns about incineration’s impacts on health, the environment, and the economy [19,20,21,22]. Incinerators can release toxic airborne chemicals (e.g., dioxins and furans) and solid residues that leach pollutants (e.g., heavy metals) into the environment [6,23], affecting air quality, groundwater, and climate change [7,24,25,26,27]. Environmental effects are complex and difficult to quantify and may lead to impacts on human health, both short-term and long-term [6,19,25,28]. The potential impacts are relevant given the increasing number of WtE incineration facilities [6,20,29].

Reducing MSW production by diverting material from waste streams to recycling in the first instance leads to better outcomes for both public health and the environment [24]. However, given that WtE-I requires continual feedstock for operation, economic benefits may incentivise waste generation and disincentivise recycling and composting [1,6,12].

In Australia, there are 17 waste incinerators currently in development or awaiting approval, which account for just under four million tonnes (megatonne, Mt) of MSW per year [30]. The greatest number of WtE facilities are in Victoria, with four currently operating or proposed [30]. WtE policy in Australia is largely managed at the state and territory level; however, the National Waste Policy Action Plan sets the targets for waste reduction and landfill avoidance [31]. Most state and territory waste management policy focuses on reducing waste production without directly mentioning incineration [20]. The Victorian Government’s Waste to Energy Framework aims to mitigate the risks of reliance on WtE-I, placing a cap of one million tonnes per year of waste processed in incineration [32]. The government of Western Australia is transitioning to a “sustainable, low waste, circular economy” under the Waste Avoidance and Recovery Strategy 2030 and currently has two large incineration projects under construction [20].

WtE-I is currently only a minor contributor to Australian energy production, with 0.08% of Australia’s energy needs being derived from MSW and ISW in 2021 [33]. Renewable energy sources contributed 8% of Australia’s energy usage in 2021 [33]. Given the accelerating social dialogue surrounding climate change, increased uptake of renewable energy sources including WtE-I is high on the political agenda.

The problem we address is the poor government engagement of communities where facilities are to be built and the seeming policy confusion at government level between waste minimisation/circular economy development and the need to reduce greenhouse gas (GHG) emissions; our contribution to this conversation is to pull out and highlight some of the pertinent issues that need to be considered by the community and governments.

In this study, we aim to build on the work of Tait et al., 2020 [19], by investigating the impacts of WtE-I on the economy, the environment, and policy, paying particular attention to trends and the potential for perverse incentives. To achieve this, we conducted a scoping review of the literature from 2016 to the present. Our purpose is to provide evidence-based and current recommendations regarding the suitability of WtE-I plants in the modern Australian context.

2. Materials and Methods

A scoping review [34,35] was conducted utilising the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines as a basis for the method [35,36].

2.1. Search Protocol

Scopus was chosen for its advanced search functionality and depth of peer-reviewed studies. The key terms were as follows: ‘waste to energy’ OR ‘WtE’ AND ‘Incineration’ AND (‘econom*’ OR ‘policy’ OR ‘perverse incentives’ OR ‘environmental impact’ OR ‘ecological impact’). The results were restricted to between 2016 and 2024 inclusively to return the most recent articles.

2.2. Abstract Screen: Inclusion Criteria

The following inclusion criteria were applied in the abstract screen: full manuscripts must be in English; papers must be focused on MSW incineration; papers must be focused on economics or the environment or policy and trends; papers must be peer-reviewed; and papers must be available online. Review papers were excluded unless the majority of their citations were dated after 2019 in an attempt to capture the influence of the contemporary regulatory environment. Titles and abstracts were screened against inclusion criteria and selected for further analysis. Where a reviewer was unsure of eligibility, abstracts were evaluated by a second researcher.

2.3. Analysis of Full Manuscripts

Included papers were allocated amongst three researchers and read in their entirety. They were analysed for the following information: study objective; method of waste to energy; information about incinerator (e.g., stack height, type of combustion); economic, environmental, and policy impacts; limitations of the study; and bias of the study. During this stage, each paper was reassessed against the inclusion criteria. Where a reviewer was unsure of eligibility, papers were evaluated by a second researcher. Papers that were funded by energy companies or which declared a conflict of interest were noted. We established preliminary themes based on the analyses and classified each paper by theme to assist with scoping. We then modified the themes to include sub-themes based on the abundance of relative papers.

2.4. Ethics Approval

The project was a scoping review using a systematic approach and was not eligible for registration with Prospero. Ethics approval was not required.

3. Results

The initial search yielded 679 search results from the Scopus database. A total of 80 papers met the inclusion criteria following the abstract screen. A total of 27 abstracts required a second opinion, and 4 of those abstracts were accepted. Six abstracts were review articles. The analysis of full manuscripts yielded 39 papers. Most papers studied more than one of our three areas of study; 28 included a focus on environment, 22 on economics, and 29 on policy and trends (Figure 1).

4. Discussion

4.1. Economic Feasibility and Circular Economy

4.1.1. High Initial Investment and Operating and Maintenance Costs with Low Thermal Efficiency

The initial costs of WtE-I include the building, reactor, turbine, components, and land. Operating costs cover MSW transport, auxiliary fuel, and labour. Revenue comes from selling electricity, steam, bottom ash (BA), and tipping fees [37].

High initial capital cost and operating and maintenance costs were recurring themes. An Argentinian study highlighted that although WtE-I can boost energy production by up to 200% compared to current MSW management systems, it requires significant investment [38]. Developing countries, like Argentina, struggle with these prohibitive costs and lack of expertise [38]. In Mexico, a proposed WtE-I plant in Guanajuato has initial costs ranging from USD 147.1 million to USD 257.4 million, making it economically unfeasible [39].

A Pakistani study noted that WtE-I projects may not be feasible due to high upfront costs, especially in cities like Islamabad with low MSW output [40]. In Baltimore, USA, a tipping fee helps WtE-I be profitable [37].

Another Mexican study highlighted high capital costs and low thermal efficiency of a proposed plant [41]. The levelised cost of electricity (LCOE) is a measure of the efficiency of a given energy source and is equal to the sum of costs of an energy source over its lifetime divided by the sum of the electrical energy produced over the lifetime. The study showed a negative logarithmic relationship between WtE-I LCOE and population size, with LCOE decreasing logarithmically with increasing population size. This population dependence of WtE-I feasibility is reiterated by another study suggesting that in Bulgaria, after accounting for MSW transport costs, plant operating costs, and maintenance costs, WtE-I plants are most economically viable in cities of greater than 50,000 people [42]. A similar population dependence was found in Brazil [10].

4.1.2. Efficiency Compared to Other Renewables

The LCOE of renewable sources in 2022 was 33 USD/MWh for onshore wind, 49 USD/MWh for utility-scale photo-voltaic (PV) solar projects, and 81 USD/MWh for offshore wind, with hydropower varying from 16 USD/MWh to 225 USD/MWh [43]. The decade-long trend of dramatically declining LCOE for PV solar and onshore wind is expected to continue.

Several studies reported a higher LCOE compared to other renewables. For example, for a proposed plant in Guanajuato, Mexico, the LCOE from WtE-I ranges from 59.39–91.48 USD/MWh over a 25-year lifespan, compared to renewables with an LCOE less than 50 USD/MWh [39]. For a proposed plant in Amol, Iran, the LCOE was 100 USD/MWh over a 20-year lifespan (over double that of renewables) with an annual energy production of 62,000 MWh, requiring rice bran auxiliary fuel (due to the low calorific value of MSW in this city) as well as supplementary financing for feasibility [44].

Conversely, a Palestinian study reported economic feasibility in two proposed incineration plants in the Palestinian Territories, with an LCOE of approximately 50 USD/MWh, which is competitive with many renewable and non-renewable sources. Government incentives enhanced both plants’ economic performance [45]. Similarly, in Java, Indonesia, the LCOE of a proposed plant was 44 USD/MWh and was therefore competitive with the current Indonesian electricity price of 69 USD/MWh [46].

LCOE calculations are based on several assumptions, particularly the discount rate, and they thus should be interpreted with caution [47]. Nevertheless, WtE-I seems either equivalent or inferior to many renewable energy sources in terms of LCOE. Future research systematically comparing the LCOE of extant and proposed WtE-I plants in comparison to renewables would be valuable.

4.1.3. Waste Composition, Circular Economy, and Recycling

The feasibility of WtE-I is strongly contingent on the MSW composition [38]; increased recycling diverts waste away from WtE-I plants, creating a perverse incentive against recycling. A Taiwanese paper highlighted the higher energy density of industrial solid waste compared to MSW, with plastics being the most calorie-dense and most GHG-emitting MSW fraction [48]. In Australia, of the approximate 3.5 Mt of plastics used in Australia per year, more than three quarters is sent to landfill [49]. Industry has historically preferred WtE to recycling, raising potential bias in the chosen treatment of plastic waste [50].

MSW is relatively energy-poor, sometimes requiring auxiliary fuel supplementation (e.g., rice bran) for WtE-I feasibility [44]. WtE-I plants require large amounts of MSW and generous public incentives to be profitable, as in the case of Lombardy, Italy [51]. A circular economy approach, with employment opportunities in collection, processing, and recycling, is more economically robust [51]. In Brazil, WtE-I strains municipal budgets and provides fewer jobs compared to waste-picker-driven recycling, which jeopardises the livelihoods of the poorest who provide the workforce. In 2013, 18 per cent of municipalities employed 387,910 waste-pickers, providing economic livelihood [52].

The MSW incineration market is expected to grow in China in line with increasing populations producing more MSW [53]. The inverse logarithmic relationship between LCOE and population suggests a greater economic opportunity for WtE-I in developing countries with growing populations [41].

4.2. Environmental Outcomes

The majority of papers discussing environmental outcomes involved case studies or modelling of prospective plants. Modelling typically compared a prospective incinerator with landfill or a combination of waste treatment including landfill. The main environmental metric studied was the relative GHG emissions compared to the baseline scenario. Some papers also considered avoiding fossil fuels, acidification, and air quality. Several studies looked at the composition of flue gas and residual bottom ash, while others considered sustainability in the face of regulatory changes.

4.2.1. Reducing Relative Greenhouse Gas Emissions

A total of 17 papers highlighted the use of WtE-I to achieve a reduction in GHG emissions compared to landfill or an alternate scenario [39,40,44,45,53,54,55,56,57,58,59,60,61,62,63,64,65]. For example, modelling has shown that, given the use of MSW incineration to generate electricity rather than landfilling, CO₂ emissions would be reduced by 88.5% in Mexico [39] and almost 50% in Jordan [64]. When rice husk was added as an auxiliary feedstock to MSW in an Iranian incinerator, it resulted in an annual reduction of 2.44 Mt of CO₂ [44]. A reduction of 3.39 Mt of CO₂ was achieved in a Pakistani model comparing MSW incineration to landfill and open burning [40]. An Indian study found that a WtE-I plant would reduce GHG emissions by 378,000 Mt of CO₂ per year from avoiding landfilling and the use of coal for energy [54]. Further studies have shown reductions in CO₂ emissions over 1 Mt (Dhaka) and 0.54 Mt (Chattogram) [55], avoided the fossil fuel use of 1.12 × 10⁶ barrels of crude oil and 2.16 × 10⁸ m³ of natural gas per year in Saudi Arabia [61], and up to 1.23 Mt of CO₂ per year for a large WtE-I plant in the Palestinian Territories [45].

The majority of papers in this group demonstrated that reductions in GHG emissions would be achieved by changing existing waste management to WtE-I. This is in addition to the resultant reduction in emissions from fossil fuels. This comparison does not consider the use of renewable energy sources in the grid. Renewable energy sources are taking up a larger proportion of grid energy across the world and especially so in the Australian context [66]. Modelling fails to compare incineration with renewable energy or to model scenarios in which a circular economy approach is taken and MSW volume is reduced. This lack of direct comparison precludes informed decisions by policy-makers about the optimum waste management policy choice that considers the full range of options.

A Chinese study notes that the use of WtE-I for energy production has the potential to transform energy structures [57], as does a study from northern Italy [60], but only where solid fuels are used for direct heating. The composition of the feedstock is important to achieve adequate temperatures for electricity generation, and augmenting the MSW stream with another material such as rice husk may not always be feasible [44].

4.2.2. Other Positive Environmental Impacts

Environmental benefits unrelated to GHG emission reductions were identified in 18 papers. A reduction in the volume of solid waste after incineration of 75% was found in both an Indian study [54] and a Jordanian study [64]. Such reductions in waste volume reduce pressure on existing landfill. The Jordanian model identified that a WtE plant would generate up to 8500 m³ per day of potable water by harvesting steam using once-through multi-stage flash technology, important in arid regions in the face of climate change. Harvesting material from bottom ash can have environmental benefits when it reduces the reliance on primary mining and natural resource processing [56].

Prospective modelling in Uganda found little impact on air quality from incineration due to limitations on dumping in the MSW stream [58]. This was corroborated by a study from northern Italy that found a minimal impact on air quality after retrofitting the plant, with emissions accounting for less than 0.001% of the acceptable limit of PM10 [67]. Improvements to indoor and outdoor air quality could be achieved by WtE-I in rural areas where solid fuel is historically used, with reductions in NOx, CO, volatile organic compounds, dioxins, polycyclic aromatic hydrocarbons, and heavy metals [60].

These benefits of WtE-I are important. However, their applicability to new or existing projects is unclear. The baseline scenario must be scrutinised, particularly in the Australian setting where solid fuel heating is not commonplace and the population level is lower.

4.2.3. Direct Environmental Impacts

We identified 10 papers that found negative environmental impacts of WtE-I at both the local and global scale. Bottom ash from an incinerator in the Azores was generally found to have acceptable levels of heavy metals; however, one out of the six samples studied had high levels of lead [68]. Environmental toxicity is possible from flue gas in African incinerators, which found high levels of SO₂, HCl, HF, NO₂, and dioxins [22]. Toxic fly ash with the potential to harm the environment was found in an Italian study [51]. Further concerns about air quality arise from several studies [52,63]. If incineration grows as population increases, African WtE-I plants are predicted to increase both their global warming potential (GWP) and acidification potential over time [22].

Other studies found negative impacts on GHG emissions compared to alternative options. A study from Baltimore found high environmental impacts of incineration, highlighting global warming potential from CO₂ and associated eutrophication impacts [37]. Alongside waste reduction and a focus on circular economy principles, biogas extraction from landfill may be beneficial to reduce methane emissions and reduce the GWP of incineration [52]. A Taiwanese study found that plastic waste must be managed due to its high GHG emission potential compared to other materials [48].

These findings highlight the GHG emissions and other negative environmental outcomes from WtE-I. The outcomes are highly dependent on the setting of the study and the parameters of the models, particularly the technology, composition of waste, and the comparison process. In areas where renewable energy is a relatively higher component of the energy grid, it is more likely that the emission profile of WtE-I will be less favourable.

4.2.4. Other Environmental Outcomes

How emissions are treated varied greatly between studies, either as standalone emissions or as avoided emissions [20]. Most studies used models to compare landfill to a prospective WtE plant to calculate the impact of GHG emissions, but few papers considered other environmental externalities such as impacts on water sources, air quality, or soil.

WtE-I technologies exhibit significant heterogeneity, which can impact the environmental impact of WtE-I; additionally, technological improvements can improve environmental outcomes [48,53]. Focusing on WtE-I may undermine efforts to encourage recycling and composting, which have positive environmental outcomes [63]. Current WtE-I sustainability modelling may be invalidated as societies progress towards a circular economy [52], effectively reducing feedstock availability for incineration and diminishing the benefits of incineration with increasing the share of renewable energy [62].

4.3. Policy and Regulatory Trends

International Trends Regarding WtE-I

In 2015, China, the EU, Japan, and the US ranked as the top four countries in terms of MSW processed by WtE-I, with designed capacities of 255,850 t/d, 207,104 t/d, 92,203 t/d, and 88,765 t/d, respectively [53].

Many of the papers are from developing countries conducting feasibility analyses, perhaps suggesting that developing countries are more open to WtE practices (e.g., Brazil, Jordan, Palestine); however, they often lack the capital and expertise to implement such projects [38,39,41,45,52,64]. Conversely, papers from more developed countries are antagonistic towards WtE-I, favouring zero-waste policies emphasising recycling [37,52,62,69]. The EU takes a more definitive stance against WtE-I than the US. For example, Sweden has implemented policies to reduce incineration and promotes a circular economy, including taxing incinerated waste—in line with European policies [52,70]; the EU does not consider WtE-I to be a sustainable activity [70,71]. Meanwhile, in the US, WtE-I is acknowledged as a renewable source of energy in some states, with concomitant tax credits and subsidies [72]. Further, there seems to be some confusion at a state and municipal level in regards to promoting WtE-I, driven by the competing interests of the WtE lobby, as well as an anti-WtE grassroots sentiment [69,72,73]. In the face of opposition, US WtE-I companies are exploring alternatives such as gasification and pyrolysis [72].

Papers from China generally exhibit a positive attitude toward WtE-I. Waste incineration is growing in China with government policy supporting the use of WtE as an alternative to burning fossil fuels [74]. There has been rapid proliferation of public–private partnerships (PPPs) in China and fierce competition in the WtE-I market [53]. It is projected that countries like China, India, Mexico, and Brazil will increase the proportion of waste incineration as part of their waste management strategy by 2050. For example, in India, some WtE-I plants are promoted by the government as part of the Clean India mission [54]. In Indonesia, waste incineration is considered part of the circular economy [75]. In Mexico, there is significant government support for WtE-I projects, with a view toward growth and expanding market scale [41]. The Palestinian government’s strategic plans (2017–2022) aim to reduce dependence on imported energy, lower CO₂ emissions, and adopt sustainable MSW disposal solutions; WtE-I aligns with national goals to enhance sustainability and energy security [45].

In developing countries, a significant amount of waste is openly dumped or burned due to the absence of landfill and recycling facilities. In these countries, WtE-I may have benefits that are not observed in developed countries, where very little waste is openly dumped or burned [76]. Nevertheless, developing countries turning to WtE-I to manage waste and provide energy need to be cognisant of the potential adverse health impacts from WtE-I facilities and the need for the facilities to be modern, highly regulated, well maintained, to use clean feedstock [19], and for the health of workers and nearby people to be monitored in order to reduce risks to health.

4.4. Public Perception and Environmental Justice

Public acceptance of WtE-I poses a significant challenge to policy-makers and the WtE-I lobby. A recurrent theme is the differing priorities between local, national, and international levels of governance regarding waste management. The concerns of residents are primarily related to the local effects of WtE-I plants such as pollution, reduced air quality, and toxic exposure. Meanwhile, national and transnational governments prioritise meeting GHG emissions targets and are stymied by the competing priorities of WtE lobbyists as well as economic constraints [52,63,69]. This often results in top-down policies that overlook local concerns. A critical theory lens emerges in some studies, which highlights how entrenched power structures propagate WtE-I technology at the expense of local environmental justice [52,63,69].

A mixed-methods case study of two WtE-I plants in Austria reveals the framing discrepancy between these opposing viewpoints. Policy elites and the WtE industry frame WtE-I as a renewable technology, strategically justifying exemptions from EU emissions trading schemes and subsidies for green energy [63]. This framing is coupled with top-down decision making that neglects local concerns regarding air quality, health risks, and divergence of waste streams away from recycling and composting.

Similar unresolved conflicts are apparent in Brazil, where local waste-pickers rely on waste-picking for their livelihoods, contributing to recycling and the circular economy [52]. In a gross violation of environmental justice, the interests of the WtE industry misalign with the local waste-pickers, illustrating the power imbalance in favour of the WtE industry given their wealth and influence over policy-makers. The authors argue that waste-picker-driven recycling offers superior economic and environmental justice outcomes [52].

The tensions between different stakeholders have been characterised as a policy paradox—a situation where policy outcomes do not reflect the expressed priorities of the policy-makers [69]. In the case of Washington DC, this sustainability policy paradox is a consequence of three factors: consistent lobbying from the WtE industry; a sense that other changes are more important given the climate crisis; and technocratic confusion about the impacts of WtE-I: WtE-I is seen both as a renewable energy source and a violation of environmental justice goals [69]. These factors enable the continuation of a WtE program that violates core city priorities.

Public perception is key to the tension between the public and the WtE lobby and policy-makers. Several studies, mostly from China, found that increased risk perception reduces the likelihood of residents approving WtE facilities; this was reflected in house prices, which decreased with proximity to a WtE-I facility [77,78]. Financial compensation, collaborative and transparent planning, and aesthetic appearance of WtE-I plants improved public trust, perceived fairness, and acceptability while ameliorating some violations of environmental justice inherent in the top-down approach [63,79,80,81,82,83].

5. Limitations

Five limitations of the present work were identified. First, WtE-I is a heterogeneous technology with many variations in terms of the type of incinerator, retrofitting, build date, and build regulations, to name a few. We were unable to control for heterogeneity because the reviewed studies did not consistently provide sufficient detail regarding the incinerator(s) studied.

Second, there was a lack of studies from Australia, thereby creating geographic sampling bias, so information regarding Australian incinerators is largely neglected. This probably reflects an underlying lack of studies in Australia due to the youth of the industry here, or it could be an artefact of our searching and screening process. This situation is further complicated by site- and country-specific variability in MSW waste composition. Nevertheless, we can reasonably expect patterns identified in other developed countries (e.g., Europe, USA) to be cautiously applied to Australia.

Third, studies comparing WtE-I with alternative WtE technologies were excluded because these alternatives are not being widely considered in the Australian context. It may be that other WtE technologies have a more favourable economic, environmental, and social profile. Future work may explore this.

Fourth, as technology advances rapidly in the field, case studies on the impact of incineration can become obsolete. Given this atmosphere of complexity and uncertainty, care must be taken when considering the advisability of a WtE-I operation.

Fifth, omission of the grey literature from our search may have missed some relevant aspects that may have contributed to the discussion.

6. Conclusions

This paper aimed to improve the understanding of the economic, environmental, and sociopolitical impacts of WtE-I in order to provide recommendations surrounding the place of WtE-I in the Australian context. The results are equivocal regarding the suitability of WtE-I, and are contingent on variables such as subsidies, land availability, specifics of WtE-I plant technology, MSW composition, the policy environment, availability of alternatives (e.g., reducing and recycling), and the extent to which the electricity grid is renewable. From the literature, we found that the negative impacts of WtE-I outweigh the benefits.

We found that WtE-I suffers from negative public perception. WtE-I plants are often built in densely populated, poorer areas at the expense of environmental and social justice for residents, who are generally opposed to WtE-I projects. This grassroots opposition to WtE-I is reflected in how locals frame WtE-I as a non-renewable, noxious technology, while policy-makers often view it as a renewable technology that can help meet their GHG targets. Although financial compensation and collaborative and transparent planning can ameliorate public opposition to some extent, social injustices persist in the form of increased threat of exposure to toxins detrimental to human and ecological health in areas near WtE-I plants [19]. For policy-makers, there has been ongoing tension between the economic and GHG benefits of WtE-I and the grassroots opposition against WtE-I, with some constituencies encountering a policy paradox in which pro-WtE-I policies are in direct contravention of the stated values of that constituency.

Environmentally, WtE-I appears generally superior to landfill. Nevertheless, there are substantial concerns regarding toxic chemicals in flue gas, heavy metals in bottom ash, and air quality around plants. The profile of environmental externalities is dependent on the regulations to which a WtE-I facility is built, retrofitting, and MSW fractions that are incinerated (e.g., plastics are the most calorific and polluting fraction). Further, we found no studies directly comparing the emission profile of WtE-I to other renewable technologies.

From an economic perspective, WtE-I has benefits under certain conditions and assumptions. These include economic superiority compared with landfill, as well as GHG emissions savings under the assumption of a fossil-fuel-driven electricity grid. Compared with renewables, WtE-I is either inferior or equal in terms of LCOE, reflecting differences in how LCOE is calculated across studies. The high capital, operational, and maintenance costs of WtE-I present a high barrier to entry. In a policy environment favouring a transition to a reduction and recycling-driven circular economy, the resultant diversion of MSW away from WtE-I means that recouping initial investments in the lifetime of a WtE-I plant may be unrealistic. Furthermore, the concomitant adoption of renewables is likely to reduce the economic and GHG benefits of WtE-I, so that continuing WtE-I will no longer be economically or environmentally justifiable.

Funds that are currently allocated towards the development of new WtE-I facilities may generate greater net benefit if allocated towards developing a reduction and recycling management approach or renewable energy infrastructure.

We predict ever diminishing economic and environmental benefits of WtE-I as the electricity grid becomes more renewable and as recycling becomes the predominant waste management strategy [62,69].

In the light of poor economic viability, unclear environmental outcomes, public health concerns and social justice issues, we recommend the following:

1.

WtE-I should not be relied upon as a significant and enduring component of the energy supply and waste management in the Australian context. Instead, Australian governments need to pursue waste minimisation and diversion policies aggressively;

2.

Australian state/territory and local governments should more proactively involve communities in waste management planning across the spectrum from reducing to disposal;

3.

More progressive waste management strategies should be adopted to facilitate the move towards renewable energy and waste minimisation, which have proven to be effective in other settings [52];

4.

In particular, governments should much more proactively engage with communities where waste management facilities are to be sited and be much more responsive to the concerns these communities may have;

5.

Where facilities are built, monitoring of health, social, and environmental impacts is essential.