One of the major challenges of the 21st century is the continuous increase of municipal solid waste (MSW) production as well as its management. According to the European Union (EU) Waste Framework Directive (WFD) 2008/98/EC, ‘any substance or object which the holder discards or intends or is required to discard’ is defined as waste. The main treatment options for MSW include, among others, landfill, incineration, recycling and composting. Both developed and developing countries have been dealing with the issue of sustainable waste management and are investigating ways to meet national and international standards in order to reduce their overall environmental impact. The main issues that have been pestering developed countries are potential ways to decrease the amount of waste going to landfill and increase the recycling and recovery of materials. The Waste Hierarchy (Figure 1
) has been affecting countries’ management options as it gives priority to preventing waste, but even if and when it is created, it should be prepared for reuse, recycling and energy recovering and only disposed to landfill if no other option is possible [1
To date many EU Member States have failed to implement waste prevention practices and therefore the regulations that have been set out by WFD [2
]. In general Southern and Eastern Europe countries are shown to have the largest implementation gaps regarding their waste management systems [2
]. Figure 2
shows EU Member States that have been performing above (blue), below (purple) and average (green) regarding their waste management.
A significant part of the Europe 2020 growth strategy has been sustainable growth towards a ‘smart, sustainable and inclusive economy’ under the notion of the circular economy, while achieving lower greenhouse gas emissions by 20% compared to levels of 1990, generating 20% of its energy from renewable sources and to increase energy efficiency by 20% [3
]. These measures could bring net savings to EU Member States, while increasing resource productivity by 30% by 2030, enhancing Gross Domestic Product (GDP) by nearly 1% and creating 2 M additional jobs while also reducing EU carbon emissions by 450 Mt by 2030 [4
]. The framework of measures for the promotion of energy efficiency is set out by Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 on energy efficiency addressing the achievement of the 20% target on energy efficiency in 2020.
In addition to those, the 2030 climate and energy framework covers EU-wide targets and policy objectives for the period 2021 to 2030, with the main targets being: at least 40% cuts in greenhouse gas (GHG) emissions (from 1990 levels), at least 32% share for renewable energy and at least 32.5% improvement in energy efficiency [5
]. Moreover the 2050 EU long-term strategy stresses the opportunities that a climate neutral Europe may bring as well as challenges that may appear, without revising the 2030 targets nor launching new policies [6
]. Overall this strategy is meant to provide a framework for the EU to achieve the Paris Agreement objectives and tackle climate change by limiting global warming to below 2 °C and attempting to limit it to 1.5 °C [6
Generally it is noticed that the global economy is highly reliant on fossil fuels such as oil, gas and coal, resulting in higher GHG emissions [7
]. Due to the volatile price of oil and the environmental degradation occurring because of fossil fuels’ use, a turn towards renewable energy sources has been noticed [9
]. Along those lines the public has become more sensitive to environmental issues, therefore most countries will be forced to make real changes in their energy mix [10
Energy efficiency improvement can provide many benefits apart from cost efficiency such as energy savings, air pollution control and GHG emission reduction as well as energy security and health benefits [11
]. It is essential to combine technological options and implementation approaches to improve energy recovery efficiency of the urban and industrial system and achieve low-carbon cities [13
]. In those regards, the development of advanced computational techniques has enabled the evaluation of energy efficiency [14
Such a tool is data envelopment analysis (DEA) which has been accepted throughout the academic community as a useful benchmarking technique [14
]. DEA is a non-parametric linear programming method used to measure the efficiency of selected decision making units (DMUs) [15
]. Initially it was intended to be applied in microeconomic studies, but comes handy in macroeconomic analysis too [16
In the present paper DEA was used at a macroeconomic level, to evaluate energy efficiency in 28 selected EU Member States with the aim to identify the current levels of efficiency as well as to assess the potential of using MSW to regain energy and ensure reliable supplies for all at reasonable prices with the least potential impacts taking the financial crisis into account too. The existing literature shows that there is a major gap in current research as researchers have not attempted to evaluate energy efficiency among EU Member States in order to understand what this means and its potential implications for the MSW sector especially under the circular economy concept. This study therefore aims to also provide EU energy efficiency levels that could act as an incentive to move more towards energy recovery from waste and realise a circular economy in full.
Apart from this Introduction, the rest of the paper is structured as presented below. Section 2
provides the background research on this topic by reviewing the main elements of energy recovery from waste (Section 2.1
) as well as the relevant existing DEA studies (Section 2.2
) with Section 3
showing the proposed methodology along with the data used. Section 4
presents the empirical findings while Section 5
analyses the results and their implications. Finally the last section (Section 6
) concludes the paper.
Under the M1 framework the highest performers are: Hungary, Luxembourg, Sweden; whereas the lowest performers are: Estonia, Bulgaria, Greece and Slovenia. For framework M2 the picture is quite similar. Table 5
shows the efficiency scores of all examined countries for the whole time period studied. Also Table 6
presents the average scores (year-wise) per country per modelling framework.
The obtained results are biased and therefore following the bootstrap technique presented in Section 3
, the bias corrected results need to be applied in our analysis. Table A1
and Table A2
) present the efficiency scores of the 28 countries, the bias corrected efficiency scores and the 95-percent confidence intervals: lower and upper bound obtained by B = 999 bootstrap replications using the algorithm described in Section 3.2
According to the bias corrected efficiency measures the countries with the higher environmental efficiency scores (i.e., >0.497) over the years are reported to be:
Framework M1: Bulgaria, Cyprus, Estonia, Greece, Lithuania, Malta and Slovenia.
Framework M2: Bulgaria, Cyprus, Estonia, Greece, Lithuania and Slovenia.
The two modelling techniques used in this analysis cannot be compared to each other since they use different inputs and outputs. A lack of common environmental policies among EU Member States can be seen in their energy efficiency levels regarding energy consumption and the relevant emissions. With regards to changes over the years and as can be seen in Figure 13
, most countries seem to maintain their efficiency scores with only Czech Republic, Finland, Ireland, Malta, Romania and Slovenia marginally improving theirs. At the same time, it can be noticed that most countries have higher environmental efficiency scores over 2010 and 2012 with a decrease after that.
The efficiency scores obtained and presented in the previous section show that EU-wise environmental efficiency levels regarding energy consumption and emissions tend to be quite low. The world’s tension level of energy supply is worsened over the years and efforts are being made to replace traditional fossil fuels with more sustainable options achieving a good balance between economic development and environmental protection [75
]. Energy from waste is the largest source of renewable energy today in the EU and is expected to hold this place until 2030, reaching a share of 60–70% [40
The ‘International Energy Efficiency Scorecard’ published in 2014 by the American Council for an Energy-Efficient Economy stresses that countries can maintain their resources, address global warming, stabilize their economies and reduce the costs of their economic outputs by using energy more efficiently [76
]. This can be seen graphically also in Figure 9
where a decrease in emissions’ level is generally noticed. The results obtained from the current analysis are also in connection with the EU’s targets for energy and climate as presented in Figure 14
In connection to that, nations have been moving towards waste-to-energy with two main objectives, namely sufficient and sustainable energy production and effective treatment of MSW by reducing its volume by about 87% [78
]. Both these two factors need to be taken into account when considering this option [79
]. A major issue to make sure this option is viable, both from an economic and an environmental perspective, is to take into consideration the resource characteristics, such as their location, amount and quality [80
]. The results of this study presenting energy efficiency should be considered to avoid unnecessary entropy production but also to make processes more cost effective and ecofriendly [81
]. The main benefits from waste-to-energy include [82
It transforms waste from a problem into a resource.
Energy generated contributes to primary energy savings from other energy sources.
It can reduce greenhouse-gas emissions when it replaces more carbon-intensive energy sources.
Waste to landfill is reduced heavily.
Waste treatment time is extremely short compared with landfills.
It also enables treatment of hazardous waste.
At the same time, the main associated risk is that those systems become highly dependent on and justify societies’ increasingly uneconomical consumption levels, while also having unintended negative effects (such as higher levels of energy and material use throughout a society, increasing upstream environmental impacts) [82
]. Moreover it is essential to create a network of the waste by-products, electricity and heat between multiple sectors throughout the world [83
]. Figure 15
presents a map of waste-to-energy plants in Europe for 2017, in which capacity is seen to be overall stable compared to 2016, with only the UK increasing its capacity.
The necessary treatment that is to be used depends highly on the nature and volume of the waste stream with the main factor taken into account being its energy content (calorific value) and as a rule of thumb waste-to-energy option should be considered when the incoming waste has an average calorific value of at least 7 MJ/kg [86
]. Table 7
presents the average net calorific values for most common MSW waste streams.
Overall the European Commission 2017 (Ref. [38
]) recommends the main technologies that could be used [88
co-incineration in combustion plants: with gasification of SRF and co-incineration of the resulting syngas in the combustion plant.
co-incineration in cement kilns.
incineration in dedicated facilities:
the use of super heaters and heat pumps
the utilisation of the energy contained in flue gas
distributing chilled water through district cooling networks.
Bio-methane for further distribution and utilisation.
In this regard Scarlat et al. [20
] perform a suitability analysis as to where waste-to-energy plants are best to be built, which can be seen graphically on Figure 16
. The potential plants (shown in green) are interrelated with the results of the current analysis, as according to their analysis, there is great potential to build plants for instance in the Czech Republic, Croatia, France, Hungary, Italy, Spain and UK. For those countries the current analysis found that energy efficiency scores are overall quite low in comparison to other countries. Also Greece and Bulgaria show a great potential for building waste-to-energy plants which makes sense according to this analysis as for these countries efficiency scores are quite low as well.
Energy efficiency levels across the 28 EU examined countries are quite low overall with only a few differentiated countries. As it stands, waste management is a crucial part in the context of the circular economy whereas prioritization needs to give to prevention, reuse, recycling and energy recovery and as a last resort disposal to landfills [89
]. Therefore the circular economy requires a better understanding of existing waste infrastructure, including location and capacity [90
]. The circular economy aims to accomplish the optimum production through the 3R principle—reduce, reuse and recycle—while minimizing resource utilization, pollution emissions and waste discarded [91
To deliver the circular economy governments need to collaborate with various partners to combine scientific research, policies and regulations, thus adopting a long-term policy framework [90
]. Along those lines, the EU Commission’s Circular Economy Package drives the treatment options that have been used by EU Member States. This package’s aim is the acceleration of Europe’s transition towards circular economy as well as the waste reduction targets across EU Member States [92
]. Therefore it is essential to preserve the worth of products, materials and resources in the economy as much as possible and minimize waste generated [4
]. Hence waste-to-energy addresses the problems of energy demand, waste management and GHG emissions at the same time, achieving a circular economy system [93
]. By 2020 196 billion kWh of sustainable energy could be produced through waste-to-energy plants which makes an equivalent of the energy produced by 6-9 nuclear stations or 25 coal power plants [94
At the same time one of the EU Commission’s priorities is also a European Energy Union which ensures reliable energy supplies at rational prices for businesses and consumers and with the least environmental impacts [95
]. This union would enhance the economy and attract investments thus creating new jobs opportunities [77
]. Competition policy in the EU is essential for the internal market with the first liberalisation directives established in 1996 (electricity) and 1998 (gas) and the second liberalisation directives adopted in 2003 [95
]. This competition policy aims mainly to ensure that companies compete fairly, providing more choices to consumers and helping reduce prices and improve quality [96
Despite these regulations, markets seem to be largely national and with relatively few cross-border trade, therefore the EU Commission has paid great attention into controlling potential mergers (such as the proposed merger between EDP and GDP in Portugal), into setting up rules for mergers and in controlling state aid to energy companies across the EU [95
]. In more detail, it is essential to have an EU competition policy, mainly to achieve [96
Low prices for all: more people can afford to buy products and businesses are encouraged to produce.
Better quality: competition encourages businesses to improve the quality of goods and services they sell and to attract more customers and expand their market share.
More choice: businesses will try to make their products unique.
Innovation: in their product concepts, design, production techniques, services, etc.
Better competitors in global markets: competition would enhance European companies’ strength outside the EU and enable them to hold their own against global competitors.
Also waste-to-energy could relieve the EU from foreign imports, for instance in 2012 it imported 4 million TJ of natural gas from Russia, whereas waste-to-energy could substitute 19% of Russian gas imports [94
]. Unfair competition will only hinder the clean energy transition as far as Member States continue to provide fossil fuel subsidies, such as direct subsidies to uneconomical coal mines, capacity mechanisms for emission intensive power plants, tax relief for company cars or diesel fuel and similar measures [77
]. More detailed research conducted in China by Zhang et al. [97
] shows that raw material price subsidies increase profits both for recycling and biofuel companies, but investment subsidies only produce greater profits for recycling companies. One important and unexpected issue that needs to be taken into account and has undoubtedly affected energy efficiency in EU Member States is the financial crisis from which the EU has been suffering severely after 2008. This can also be noticed in the efficiency scores obtained through the present analysis, whereas efficiencies have decreased after 2012 when the crisis became more imminent.
As for the future steps, the EU plans for a climate-neutral Europe by 2050 through investments to realistic technological solutions, the empowering of citizens and aligning action in key areas such as industrial policy, finance, or research [6
]. In those regards studies suggest that the potential for using heat from waste could be an equivalent to 200 billion kWh per year by 2050 [90
]. Therefore it is essential to already have consultations with young people, citizens affected by the energy transition, inventors, social partners and civil society, mayors and other politicians to show the potential of realizing this energy transition [78
6. Conclusions and Policy Implications
The current paper examines energy efficiency across 28 selected EU Member States and reviews the potential for energy recovery from waste according to the efficiency scores obtained for the examined Member States. The efficiencies are assessed through DEA under CRS and the following variables are examined: final energy consumption, GDP, labour, capital, population density, NOx emissions (from energy), SOx emissions (from energy) and GHG emissions (from energy) from Eurostat data and for the years 2008, 2010, 2012, 2014 and 2016. The two models that are designed use two outputs one desirable (GDP) and one undesirable (aerial gas emissions – GHG, SOx and NOx) with different inputs in each case.
The bias corrected efficiency scores show that overall Bulgaria, Cyprus, Estonia, Greece, Lithuania and Slovenia are efficient under both frameworks. Also most countries seem to maintain their efficiency scores with only the Czech Republic, Finland, Ireland, Malta, Romania and Slovenia marginally improving theirs. At the same time, it can be noticed that most countries have higher environmental efficiency scores over 2010 and 2012 with a decrease after that.
These efficiency scores show that EU-wise environmental efficiency levels regarding energy consumption and emissions tend to be quite low overall, therefore it is suggestible to move towards waste-to-energy with two main objectives, namely sufficient and sustainable energy production and effective treatment of MSW. This option would enhance the circular economy, whereas prioritization needs to give to prevention, preparation for reuse, recycling and energy recovery through to disposal, such as landfilling. Waste to energy addresses the problems of energy demand, waste management and GHG emissions simultaneously.
Together with the EU Commission’s competition strategy, these options would ensure reliable energy supplies at rational prices for businesses and consumers and with the least environmental impacts. Along with these and taking into account the current analysis’ results, it is essential to account for the financial crisis which affects EU since 2008. Namely the efficiency scores show a decrease after 2012 when the crisis became more imminent (Figure 13
). Regarding future steps towards a climate neutral Europe, investments into technology along with the empowering of citizens and industry need to be considered.
The models of the present research could be enriched with additional control variables which could incorporate specific characteristics of EU countries, such as their technological level regarding waste management especially, their institutional background and their education level to name a few. Moreover once data become available it would be useful to expand this research with more recent data to better reflect today’s situation.