Ramón Sala-Garrido

• PhD
• Professor (Full) at University of Valencia

Within the context of the circular economy, improving the eco-efficiency (EE) in the management of municipal solid waste (MSW) is of paramount importance. For informed decision-making, understanding the dynamics of EE, i.e., eco-productivity change (EPC) and its drivers—efficiency change, technical change and scale change—have revealed as essential...

Purpose The present research aims to develop a Terminal Competitiveness Index (TCI) applied to the container terminals located in the Hamburg – Le Havre range, which is an area characterised for its intense container activity. The main components of the TPCI are productivity, foreland connectivity and infrastructure. Design/methodology/approach To...

Water utilities provide water and sanitation services in monopolistic conditions. Hence, assessing their performance through benchmarking is crucial for proper regulation. This research addresses the limitations of self-evaluation Data Envelopment Analysis (DEA) models commonly used for benchmarking water utilities’ efficiency. Given that these mod...

Enhancing the eco-efficiency of municipal solid waste (MSW) services is pivotal for the shift toward a circular economy. Although the Data Envelopment Analysis (DEA) method is widely used, it is susceptible to overfitting, potentially distorting eco-efficiency assessments. This study applies the efficiency analysis tree (EAT) method, which synergiz...

Moving toward a circular economy requires improvement of the economic and environmental performance of municipalities in their provision of municipal solid waste (MSW) services. Understanding performance changes over years is fundamental to support decision-making. This study employs the Luenberger-Hicks-Moorsteen productivity indicator to evaluate...

Assessing the eco‐efficiency of municipalities regarding the provision of solid waste services is a useful tool for improving its sustainability. However, robust, and reliable methods are needed to benchmark the performance of municipalities. Data envelopment analysis (DEA) methods typically used to assess the eco‐efficiency of municipal solid wast...

In the face of climate change, it becomes crucial to motivate action and policies within water companies towards achieving carbon neutrality. Estimating the economic consequences of inaction can be a compelling catalyst for change. In this study, the carbon inefficiency and overuse of energy among a selection of English and Welsh water companies we...

The measurement of performance within the water industry holds significant importance for policymakers, as it can help guide decision-making for future development and management initiatives. In this study, we apply data envelopment analysis (DEA) cross-efficiency techniques to evaluate the productivity change of the Chilean water industry during t...

Water companies provide essential services to society, such as drinking water and sanitation. Improving the management of these companies is fundamental for evaluating their performance. This study employs cross-efficiency data envelopment analysis techniques to assess a sample of water companies during the years 2010–2018. The assessment focuses o...

Evaluating the eco-efficiency of wastewater treatment plants (WWTPs) is crucial for enhancing environmental and economic performance in the water utility sector. Previous studies in this area estimated WWTP eco-efficiency through self-evaluation, which might have led to overestimation and biased policy recommendations. To address these issues, this...

Wastewater treatment plants (WWTPs) are energy intensive facilities. Controlling energy use in WWTPs could bring substantial benefits to people and environment. Understanding how energy efficient the wastewater treatment process is and what drives efficiency would allow treating wastewater in a more sustainable way. In this study, we employed the e...

Port connectivity has become a key factor for the competitiveness of countries, ports and importing and exporting companies. In this regard, industries integrated into global value chains are dependent of shipping services and, consequently, the level of port connectivity determines their access to international markets in a reliable and flexible w...

Benchmarking the dynamic performance of water companies is a powerful tool to develop sound policies. However, it requires the use of reliable and robust methods and quality of data. In this study, the stochastic nonparametric envelopment of data (StoNED) method was employed to assess productivity change and eco-productivity change of a sample of C...

The regulation of water companies (WCs) is essential to protect the interests of citizens, as companies are natural monopolies. Consequently, several methodological approaches are applied by water regulators to benchmark the performance of WCs, with data envelopment analysis (DEA) being one of the most widely applied. However, traditional DEA model...

Improving the management of municipal solid waste (MSW) is fundamental to promote circular economy and sustainability. Unsorted waste involves negative environmental impacts which often are ignored in economic feasibility studies due to its difficult valuation. In this study the shadow price of unsorted waste using the directional distance function...

Eco-efficiency assessment of municipal solid waste (MSW) suppliers is a useful tool in the transition to a circular economy. Furthermore, it provides evidence of the economic and environmental performance of municipalities that can be used for decision-making and/or elaboration of regulatory policies. In this study, eco-efficiency scores were compu...

The path to a sustainable management of the urban water cycle requires the assessment of both operational and quality-adjusted efficiency in a unified manner. This can be done by the use of non-radial Data Envelopment Analysis models. This study used Range Adjusted Measure models to evaluate the operational, quality-adjusted, and operational & qual...

Drinking water treatment systems (DWTSs) are energy intensive facilities, and are an example of the water-energy nexus. Benchmarking energy efficiency is a valuable tool for improving the economic and environmental performance of such facilities. Data envelopment analysis (DEA) is typically used to assess efficiency, allocating flexible weights (FS...

Water leakages and unplanned water supply interruptions are relevant variables in the provision of drinking water since they directly impact customers and the economic and environmental performance of water companies. For the first time, in this study, we estimated specific efficiency scores for these two quality-of-service variables using the mult...

Improving eco-efficiency in the provision of municipal solid waste plays an important role for a sustainable economy. Eco-efficiency of municipal solid waste service providers (MSWSPs) has been generally assessed using the conventional data envelopment analysis (DEA) method. However, this approach is sensitive to data noise and has no statistical p...

Understanding water-energy nexus in the provision of drinking water services is a challenge which has outstanding relevance in the current climatic emergency. Environmental efficiency and eco-efficiency assessment of water companies are two useful tools to address this challenge. In this study, we estimated hyperbolic and enhanced hyperbolic distan...

Getting a good understanding regarding the economic and environmental performance of water utilities is of great importance to achieve the goal of an efficient and sustainable industry. In this study, we apply the range adjusted measure (RAM) data envelopment analysis (DEA) model to evaluate the integrated (production and environmental) efficiency...

The firms’ performance assessment for regulation requires estimating profit change and its drivers. This study estimates and decomposes profit changes into components such as output and input price changes, output growth, and markups. Using the stochastic frontier analysis, we compute the drivers of productivity change, such as technical change, re...

Reducing greenhouse gas (GHG) emissions and energy costs has been one of the main challenges faced by the water sector. This study provides a quantification of energy costs and GHG emissions efficiency of a sample of the English and the Welsh water companies over the period of 2013-2018. In doing so, the multi-directional data envelopment analysis...

Access to safe, reliable and affordable drinking water is a human right that should be achieved without neglecting Sustainable Development Goal 13 of the United Nations related to climate action. The production of drinking water involves using a non-negligible amount of energy, leading to relevant economic costs and greenhouse gas (GHG) emissions....

Improper municipal solid waste (MSW) management leads to contamination of water, soil and air with negative impacts on human health. Moreover, not dealing with residual waste has huge implications for meeting circular economy targets. Understanding how much it costs could lead to a better quality of service and boost environmental sustainability. T...

This study applies a two-stage network structure model to evaluate water service providers cost and operational performance embracing service quality variables. An empirical analysis of the Chilean water and wastewater industries over the 2010–2018 period is presented. Moreover, in the second stage of analysis, we analyzed the impact of a set of ex...

Moving towards a circular and sustainable economy requires improving the management of municipal solid waste (MSW) increasing recycling rates while minimising unsorted waste and operational costs. It is essential to evaluate the economic and environmental efficiency of MSW services. Previous studies focused on developed countries and employed radia...

Purpose The purpose of this paper is to estimate and compare the efficiency of several water utilities using three frontier techniques. Moreover, this study estimates the impact of several qualities of service variables on water utilities’ performance. Design/methodology/approach The paper utilizes three frontier techniques such as data envelopmen...

This study evaluates and compares the dynamic eco-efficiency of municipalities with publicly owned, privately owned, and mixed ownership solid waste utilities by estimating the Meta-frontier Malmquist-Luenberger productivity index for a sample of 68 major Italian towns. On average, the eco-productivity of Italian waste service providers increased b...

The water production system is a complex network and policy makers can get a better insight into how the system operates if they know how efficient each sub-process is. In this study, and for the first time, we employ a two-stage network Data Envelopment Analysis model to evaluate the eco-efficiency of water services in England and Wales, integrati...

Moving to a more sustainable and low-carbon footprint urban water cycle is essential in the light of climate change. In this paper, we estimate the implicit cost of reducing greenhouse gas (GHG) emissions for several English and Welsh water companies from 2013 to 2019. Using econometric techniques, we compute the shadow prices of direct and indirec...

The water industry encompasses a wide variety of water companies operating with different production technologies. This study evaluated and compared changes to the productivity of several fully private water companies (FPWCs) and concessionary water companies (CWCs). Specifically, the cost Malmquist productivity index was estimated by integrating i...

Assessing the productivity change of water companies provides relevant information for both water regulators and companies’ managers. Past research has illustrated that different indicators and indexes have been applied although not all of them are equally reliable. Thus, this study evaluates the total factor productivity (TFP) change and its drive...

The assessment of performance of water companies is essential for their regulation. In doing so, several variables and models can be employed. This study evaluates and compares the performance of a sample of English and Welsh water companies from the operational, environmental and eco-efficiency perspectives by applying the non-radial data envelopm...

Reducing greenhouse gas (GHG) emissions involves effort from different sectors of the economy, including the water and sewerage industry. This study estimates the marginal cost of curtailing GHG emissions in the water and sewerage industry using stochastic frontier analysis techniques for a sample of ten English and Welsh water and sewerage compani...

Improving the eco-efficiency of municipalities in the provision of municipal solid waste (MSW) services is fundamental in the context of a circular economy. This study evaluates the eco-efficiency of a sample of Spanish municipalities, integrating the total cost as input, recyclable waste as desirable output, and unsorted waste as undesirable outpu...

In regulated industries, such as the water industry, it is of great significance to estimate productivity change as it helps policy makers to evaluate the effectiveness of regulatory regime and industry performance. In this paper, and for the first time, a translog input distance function was used to estimate and decompose productivity change into...

Analyzing costs and greenhouse gas (GHG) emissions could be of great importance for the water utilities to supply water services in a healthy and sustainable manner. In this study, we measured the eco-efficiency of several water utilities in England and Wales by incorporating GHG as an undesirable output. For the first time, we evaluated the eco-ef...

The assessment of the productivity change of water utilities provides essential information to sector managers and regulators. This study uses the Luenberger-Hicks-Moorsteen Productivity Indicator (LHMPI) to evaluate productivity change as it can be further decomposed into three components namely technical change (TC), technical efficiency change (...

Evaluating the quality of service (QS) provided by water companies is essential to benchmark and regulate them. Composite indicators (CIs) are a useful tool for this as they consist of aggregated multiple performance indicators in a single index, providing a holistic assessment of the QS of water companies. In this study, the novel ‘benefit of doub...

The assessment of wastewater treatment plant (WWTP) performance has gained the interest of water utilities and water regulators. Eco-efficiency has been identified as a powerful indicator, as it integrates economic and environmental variables into a single index. Most previous studies have employed traditional data envelopment analysis (DEA) for th...

Reducing greenhouse gas emissions is a major challenge faced by cities seeking to improve their environmental sustainability. Doing so requires a good understanding of the costs associated with lowering emissions and factors that may influence this cost. This study estimated the marginal abatement cost of reducing both direct and indirect CO2 emiss...

Understanding what drives changes in regulated water companies' costs is of great relevance to water regulators. This study decomposes and estimates the change in total costs for a sample of ten water and sewerage companies in England and Wales from 1993 to 2016. The results demonstrate that companies' total costs increased over time due to increas...

Conventional performance assessments of water companies ignore the external costs due to water supply outages. To overcome this gap, we evaluate the impact of external costs of unplanned supply interruptions on the efficiency of water companies. Two efficiency metrics, internal technical efficiency (ITE), and total technical efficiency (TTE), were...

The assessment of water companies’ efficiency, productivity and quality of service is part of the process to set water tariffs and therefore, is relevant for regulators and customers. However, the water industry involves several heterogeneous water companies. Following a pioneering approach, this study estimates productivity change and its drivers...

This paper analyses the efficiency of players in the Spanish Soccer League for the 2009/2010 season using a metafrontier version of data envelopment analysis (DEA) methodology. It is possible to apply a metafrontier approach if separate frontiers can be identified for different groups in the data set. In our case, we divide the sample of players in...

Evaluating changes in profit, price and productivity over time can be of great importance for regulated water industries. We investigate the drivers of profit, price (capital, labour and other inputs) and productivity change (cost efficiency change, technical change and scale effect) and the recipients of productivity change (consumers, the busines...

Evaluating the efficiency of wastewater treatment plants (WWTPs) is highly relevant to improve their performance from an economic and environmental perspective. The issue is even more critical in countries where WWTPs are benchmarked to regulate water companies and define WWTPs' economic and environmental objectives. Despite the large number of pre...

In monopoly services that provide drinking water, it is of paramount importance to evaluate the total factor productivity (TFP) change of water companies. Most of the previous studies have computed the Malmquist productivity index (MPI) by applying non-parametric methods. By contrast, following a pioneering approach, in this study, we estimated the...

This study evaluates, for the first time, the energy efficiency of a sample of drinking water treatment plants (DWTPs) using the data envelopment analysis (DEA) tolerance method, which is based on the simulation of scenarios to integrate data variations. The integration of data uncertainty in energy efficiency estimation changes drastically results...

It is essential to assess the productivity of wastewater treatment plants (WWTPs)to improve their economic and technical performance over time. In doing so, reliable indexes should be used to avoid biased conclusions leading to unsuccessful policy and managerial measures. Ratio-based indexes are typically employed, but are infeasible when any of th...

The assessment of profit, productivity, and price change over time is valuable for regulators and companies when setting tariffs. This paper innovates by comparing profit, price, and productivity changes for English and Welsh water services between water and sewerage companies (WaSCs) and water-only companies (WoCs) over the period of 2001–2009. Th...

To achieve energy and climate goals, the energy performance of current and future drinking water treatment plants (DWTPs) must be improved. A few studies have evaluated the energy efficiency of these facilities using data envelopment analysis (DEA), however, they have ignored the deterministic nature of the DEA method. To overcome this limitation,...

Most previous studies evaluating the effect of ownership on the performance of water companies have ignored the fact that there are several types of private water companies. In this study, we instead recognize that private water companies can differ considerably in how they are managed, based on whether their infrastructure is privately or publicly...

One of the United Nations Sustainable Development Goals is to provide access to safe and clean drinking water. However, treating raw water in facilities currently involves using a non-negligible amount of energy, and the fossil fuels used are both expensive and emit greenhouse gases when combusted. Previous studies have evaluated the energy perform...

Interest in evaluating productivity changes in water companies has increased in recent years. In this paper, for the first time, we employ the Luenberger-Hicks-Moorsteen Productivity Indicator (LHMPI) to evaluate productivity changes in a sample of Chilean water companies from 2010 to 2016. Productivity change estimations obtained by both the Luenb...

This study proposes to evaluate the sustainability of water companies through time by using a new approach, one that involves a dynamic synthetic indicator derived from goal programming techniques. This dynamic indicator approach incorporates catch-up and innovation indices, which enables one to identify the main factors that drive changes in susta...

Eco-efficiency assessment is a useful tool for improving the sustainability of wastewater treatment plants (WWTPs). However, it is a complex task that requires the integration of several performance indicators into a single index. Data envelopment analysis (DEA) is established as a highly effective methodology for achieving this as it permits the i...

Wastewater treatment plants (WWTPs) are energy intensive facilities; therefore increased pressure has been placed on managers and policy makers to reduce the facilities’ energy use. Several studies were conducted to compare the energy intensity (EI) of WWTPs, which showed large dispersion in EI among the facilities. In the present study, the degree...

Improving eco-efficiency of wastewater treatment plants (WWTPs) has been identified as being essential for achieving urban sustainability. Several previous papers have evaluated the eco-efficiency of WWTPs using data envelopment analysis (DEA) models. However, those models provided only a static assessment in that they ignored possible fluctuations...

Benchmarking the efficiency of water companies is essential to set water tariffs and to promote their sustainability. In doing so, most of the previous studies have applied conventional data envelopment analysis (DEA) models. However, it is a deterministic method that does not allow to identify environmental factors influencing efficiency scores. T...

The importance of ports as links in the maritime transport and their weight in the global economic development is unquestionable. Identifying the most efficient ports and the best practices is basic for ports’ managers, customers and authorities. However, ports are not homogeneous units because they are specialised in terms of traffic and services....

Evaluating the productivity growth of water and sewerage companies (WaSCs) is useful to ensure their long-term sustainability and to protect the interests of customers. Previous studies that assessed the WaSCs’s productivity provided an aggregate productivity index without accounting for the specific contribution of the variables involved in the an...

To provide safe drinking water to urban populations, raw water must be treated in drinking water treatment plants, which are energy-intensive facilities. Previous studies have assessed energy intensity (EI: unit of energy required per unit of treated water) of conventional drinking water treatment plants, but they ignored variations related to wate...

The assessment of productivity change and its drivers across water companies and over time is a powerful tool for both regulators and companies when setting water tariffs. Water and sewerage companies (WaSCs) and water only companies (WoCs) provide different services. Hence, their productivity change cannot directly be evaluated jointly. In this pa...

Currently, water and sewer companies face the challenge of improving their quality of service to customers (QSC). Performance indicators are essential to monitor and benchmark the QSC of water companies; however, individual indicators do not provide a holistic evaluation of the quality of water and sewer services provided to customers. This study p...

The assessment of productivity change across companies and over time is of great importance for water utilities managers and regulators. In this paper, for the first time, we apply the Färe-Primont productivity index (FPI) to evaluate the productivity change for the 10 water and sewerage companies (WaSCs) and 12 water only companies (WoCs) in Engla...

Assessing productivity change over time and identifying its determinants is a valuable tool for water regulators when setting water tariffs. However, in a price cap regulatory framework such as in England and Wales policy makers should give attention to quality of service issues. Previous studies that assessed the productivity change of the English...

Benchmarking the performance of wastewater treatment plants (WWTPs) is essential for promoting their long-term sustainability. Recent research has applied data envelopment analysis (DEA) models to evaluate the efficiency of WWTPs providing a synthetic index of their performance. However, the traditional DEA is a deterministic method; therefore, reg...

Water supply interruptions directly affect customers, and customers should be compensated accordingly. However, few water regulators have applied compensation policies given the difficulty of estimating the economic value of compensation to customers. In this study, a pioneering approach based on the concept of shadow prices is proposed to determin...

Water scarcity is one of the main problems faced by many regions in the XXIst century. In this context, the need to reduce leakages from water distribution systems has gained almost universal acceptance. The concept of sustainable economic level of leakage (SELL) has been proposed to internalize the environmental and resource costs within economic...

This paper evaluates the efficiency of water and sewerage companies (WaSCs) by applying the weighted Russell directional distance model. This is a non-radial data envelopment analysis (DEA) model that allowed us to obtain an individual efficiency score for each input and output considered in the assessment. This study provides a pioneering approach...

Efficiency assessment of water and sewerage companies (WaSCs) has attracted considerable attention both for water company managers and water regulators. Within the methodological approaches that can be applied to estimate efficiency scores, data envelopment analysis (DEA) is the most widely applied technique. In spite of the positive features of DE...

Improving the performance of wastewater treatment plants is essential to ensuring their long-term sustainability. Most of the previous studies on this topic have assessed the techno-economic efficiency of wastewater treatment plants and ignored the emission of greenhouse gases. For the first time, the weighted Russell directional distance model was...

The need to increase water productivity in agriculture has been stressed as one of the most important factors to achieve greater agricultural productivity and sustainability. The main aim of this paper is to investigate whether there are differences in water use efficiency (WUE) between farmers who participate in water markets and farmers who do no...

International cross-comparisons of the performances of water utilities can provide data to improve the efficiency and innovation of these companies. However, such comparisons face issues with data comparability because heterogeneity restricts the ability to compare sets directly. Traditional methods to assess efficiency assume that units operate un...