The development of a power system based on high shares of renewable energy sources puts high demands on power grids and the remaining controllable power generation plants, load management and the storage of energy. To reach climate protection goals and a significant reduction of CO2, surplus energies from fluctuating renewables have to be used to defossilize not only the power production sector but the mobility, heat and industry sectors as well, which is called sector coupling. In this article, the role of wastewater treatment plants by means of sector coupling is pictured, discussed and evaluated. The results show significant synergies—for example, using electrical surplus energy to produce hydrogen and oxygen with an electrolyzer to use them for long-term storage and enhancing purification processes on the wastewater treatment plant (WWTP). Furthermore, biofuels and storable methane gas can be produced or integrate the WWTP into a local heating network. An interconnection in many fi... [more]

The deregulation of the electricity markets in the European Union and the transformation caused by digital technologies and customer-centric strategies have altered the industry ecosystem, forcing companies to adapt to the new scenario. This research study aims to give a global overview of the digital transformation and channel integration of free-market electricity retailers in Spain from a consumer’s perspective. The analysis includes all free-market electricity retailers that operate at the national scale, explores the level of digital transformation and channel integration of these companies based on a structured set of indicators, and measures them using the mystery shopper technique. The results show important differences between leading retailers and the rest of companies, evidence an important lag of the sector when compared to other retail markets and an overall lack of multichannel and omnichannel strategies, show a strong effort of retailers in online billing and self-servic... [more]

While indoor comfort represents a widely investigated research topic with relation to sustainable development and energy-demand reduction in the built environment, outdoor comfort remains an open field of study, especially with reference to the impacts of climate change and the quality of life for inhabitants, particularly in urban contexts. Despite the relevant efforts spent in the last few decades to advance the understanding of phenomena and the knowledge in this specific field, which obtained much evidence for the topic’s relevance, a comprehensive picture of the studies, as well as a classification of the interconnected subjects and outcomes, is still lacking. This paper reports the outcomes of a literature review aimed at screening the available resources dealing with outdoor thermal comfort, in order to provide a state-of-the-art review that identifies the main topics focused by the researchers, as well as the barriers in defining suitable indexes for assessing thermal comfort i... [more]

The aim of the article was to analyze the decision-making process of professional drivers regarding the choice of new engine oil with additional attention to the eco-friendliness aspect of the product. Survey data were collected from Polish consumers, using a self-administered questionnaire. The main data analysis tools used in the study were finite mixture models. It was found that professional drivers do not constitute a single homogenous group. They cluster into two segments with differing importance profiles. The largest consumer segment, over 80% of consumers, consider the quality classification, viscosity classification, and OEM specifications as the most important criteria during the decision-making process. The importance of oil being environmentally friendly is a factor moderately differentiating the subgroups. In the first segment, a strong preference for engine oil with the same technical parameters as the previously purchased one, but additionally marked as environmentally... [more]

The agro-environmental impact of supplemented biochar manure pellet fertilizer (SBMPF) application was evaluated by exploring changes of the chemical properties of paddy water and soil, carbon sequestration, and grain yield during rice cultivation. The treatments consisted of (1) the control (no biochar), (2) pig manure compost pellet (PMCP), (3) biochar manure pellets (BMP) with urea solution heated at 60 °C (BMP-U60), (4) BMP with N, P, and K solutions at room temperature (BMP-NPK), and (5) BMP with urea and K solutions at room temperature (BMP-UK). The NO3−−N and PO4−−P concentrations in the control and PMCP in the paddy water were relatively higher compared to SBMPF applied plots. For paddy soil, NH4+−N concentration in the control was lower compared to the other SBMPFs treatments 41 days after rice transplant. Additionally, it is possible that the SBMPFs could decrease the phosphorus levels in agricultural ecosystems. Also, the highest carbon sequestration was 2.67 tonnes C ha−1 i... [more]

The rapid economic growth of China in the past decades has been accompanied by serious environmental problems. In the country, both economic development and environmental pollution show a geographically uneven pattern, with some regions displaying significantly better performance than others in economic and/or environmental performance. To understand the regional pattern of economic and environmental performance, this article analyzes sustainable development at the Chinese provincial level. Three sustainability indices are defined and computed by combining economic and environmental factors based on data envelopment analysis. The three indices correspond to the concepts of natural disposability, managerial disposability and null-joint relationship, respectively. Natural (managerial) disposability prioritizes economic (environmental) outcome in measuring sustainability. Furthermore, the assumption of a null-joint relationship implies that undesirable outputs are by-products of desirable... [more]

The development of the road construction sector determines the consequences on consumption of non-renewable resources, energy expenditure and environmental pollution. Recent sustainability issues have highlighted the importance of efficient design and quality-oriented techniques in this sector, due to the huge amount of materials involved in construction and maintenance activities. Thus, it is necessary to properly quantify the environmental impacts of asphalt mixtures used for pavement construction, considering the whole life cycle of the products. Life cycle assessment (LCA) represents the most appropriate methodological framework for assessing the environmental burdens of a product, from raw material acquisition to final disposal. A common problem for LCA is the lack of primary data useful to calculate the product eco-profile, for a specific production process. In this context, there is generally limited reliable and accurate data regarding the asphalt plant production phase, which... [more]

This paper explores the advantages of using relative free energy instead of exergy to build a mathematical theory of thermodynamic costs to diagnose malfunctions in thermal systems. This theory is based on the definition of a linearized characteristic equation that represents the physical behavior of each component. The physical structure of the system described by its energy interrelationships is called “primal”, and its derivatives are the costs and consumptions. The obtained costing structure is the mathematical “dual” of its primal. The theory explains why the F and P cost assessment rules and any other suggestion may (or may not be) rational under a given disaggregation scheme. A result of the theory is a new thermodynamic function, called the relative free energy, and a new parameter called deterioration temperature due to a component’s deterioration cause, characterized by a h-s thermodynamic trajectory describing the effects on the exiting stream. The relative free energy funct... [more]

Biowaste represents a significant fraction of municipal solid waste (MSW). Its separate collection is considered as a useful measure to enhance waste management systems in both the developed and developing world. This paper aims to compare the environmental performance of three market-ready technologies currently used to treat biowaste—biowaste composting, fermentation, and biowaste incineration in waste-to-energy (WtE) plants as a component of residual municipal solid waste (RES). Global warming potential (GWP) was applied as an indicator and burdens related to the operation of facilities and credits obtained through the products were identified. The environmental performance of a WtE plant was investigated in detail using a model, implementing an approach similar to marginal-cost and revenues, which is a concept widely applied in economics. The results show that all of the treatment options offer an environmentally friendly treatment (their net GWP is negative). The environmental per... [more]

The paper analyses the indoor environment in two modern intelligent buildings located in Poland. Measurements of air and globe temperatures, relative humidity and carbon dioxide concentration in 117 rooms carried out in the space of 1.5 years were presented. Thermal comfort of the occupants has been investigated using a questionnaire survey. Based on 1369 questionnaires, thermal sensation, acceptability and preference votes were analysed in view of their interdependency as well as their dependency on operative temperature, which proved to be very strong. It has been found that the respondents did not completely rate thermal comfort and indoor environment quality as very high, although the overwhelming sensations were positive. Apart from the operation of heating, ventilation and air conditioning (HVAC) systems, this might have also been the cause of individual human factors, such as body mass index, as tested in the study, or the finding that people were generally in favour of a warmer... [more]

Microalgae can be a future source of biomass with a wide range of applications, including its use to solve current environmental issues. One of the main variables for microalgal cultivation is the light supply: (i) its intensity that often does not present a uniform spatial distribution inside the culture; (ii) photoperiod; and (iii) spectrum. Therefore, this study aims to evaluate the growth of the microalgae Chlorella vulgaris in a tubular photobioreactor with compound parabolic collectors (CPCs) under outdoor conditions. The effect of ultraviolet and visible radiation on biomass productivity and nutrients (nitrogen and phosphorus) uptake was assessed. The maximum biomass productivity was (5 ± 1) × 10−3 g·L−1·h−1, and the specific growth rates ranged from (1.1 ± 0.3) × 10−2 to (2.0 ± 0.6) × 10−2 h−1. Regarding nutrient uptake, initial removal rates of (0.9 ± 0.4) mg N·L−1·h−1 for nitrogen and (0.17 ± 0.04) mg P·L−1·h−1 for phosphorus were reached. These values increased with visible... [more]

The European Union (EU) is considered one of the most economically developed regions worldwide. It was driven by the mining industry for several decades. Despite certain changes in this area, a number of mineral and energy resources are still being mined in the EU. Nevertheless, mining activities are accompanied by many unfavorable phenomena, especially for the environment, such as greenhouse gas and air pollutant emissions. The great diversity of the EU countries in terms of the size of the “mining and quarrying” sector means that both the volume and structure of these emissions in individual countries varies. In order to assess the current state of affairs, research was conducted to look at the structure and volume of these emissions in individual EU countries. The aim of the study was to divide these countries into homogenous groups by structure and volume of studied emissions. In order to reflect both the specificity and diversity of the EU countries, this division was based on the... [more]

In Poland, unutilised land occupies approximately two million hectares, and it could be partly dedicated to the production of perennial crops. This study aimed to determine the environmental impact of the production of giant miscanthus (Miscanthus x giganteus J.M. Greef & M. Deuter). The experiment was set up on a low-fertility site. The crop was cultivated on sandy soil, fertilised with digestate, and mineral fertilisers (in the dose of 85 and 170 kg ha−1 N), and was compared with giant miscanthus cultivated with no fertilisation (control). The cradle-to-farm gate system boundary was applied. Fertilisers were more detrimental to the environment than the control in all analysed categories. The weakest environmental links in the production of miscanthus in the non-fertilised treatment were fuel consumption and the application of pre-emergent herbicide. In fertilised treatments, fertilisers exerted the greatest environmental impact in all the stages of crop production. The production and... [more]

As households get smaller worldwide, the extent of sharing within households reduces, resulting in rising per capita energy use and greenhouse gas (GHG) emissions. This article examines for the first time the differences in household economies of scale across EU countries as a way to support reductions in energy use and GHG emissions, while considering differences in effects across consumption domains and urban-rural typology. A country-comparative analysis is important to facilitate the formulation of context-specific initiatives and policies for resource sharing. We find that one-person households are most carbon- and energy-intensive per capita with an EU average of 9.2 tCO2eq/cap and 0.14 TJ/cap, and a total contribution of about 17% to the EU’s carbon and energy use. Two-person households contribute about 31% to the EU carbon and energy footprint, while those of five or more members add about 9%. The average carbon and energy footprints of an EU household of five or more is about... [more]

Knowledge and research tying the environmental impact and embodied energy together is a largely unexplored area in the building industry. The aim of this study is to investigate the practicality of using the ratio between embodied energy and embodied carbon to measure the building’s impact. This study is based on life-cycle assessment and proposes a new measure: life-cycle embodied performance (LCEP), in order to evaluate building performance. In this project, eight buildings located in the same climate zone with similar construction types are studied to test the proposed method. For each case, the embodied energy intensities and embodied carbon coefficients are calculated, and four environmental impact categories are quantified. The following observations can be drawn from the findings: (a) the ozone depletion potential could be used as an indicator to predict the value of LCEP; (b) the use of embodied energy and embodied carbon independently from each other could lead to incomplete a... [more]

This paper provides an investigation into the sustainability of the electrical system in Spain. The analysis covers historic inventories of power generation, installed capacity and technology mix since 1990 and also contemplates four alternative projections for 2030 and 2050. The sustainability is evaluated using eight indicators that provide objective information about the environmental (climate change, fossil depletion, ozone layer depletion, terrestrial acidification, human toxicity and photochemical smog), economic (levelized cost of electricity) and socio-economic (direct employment) performance of the system. The results show an increase in the magnitude of the environmental impacts between 1990 and 2008, due to a growing power demand triggered by economic expansion. After 2008, the environmental performance improves due to the economic recession and the penetration of renewable energies. Overall, the cost of power generation remains rather stable as rising expenses generated by... [more]

Research on various security technologies has been actively underway to protect systems from attackers. However, attackers can secure enough time to reconnoiter and attack the target system owing to its static nature. This develops asymmetric warfare in which attackers outwit defenders. Moving target defense (MTD) technologies, which obfuscate the attack surface by modifying the main properties of the potential target system, have been gaining attention as an active cyber security technology. Particularly, network-based MTD (NMTD) technologies, which dynamically mutate the network configuration information, such as IP and ports of the potential target system, can dramatically increase the time required for an attacker to analyze the system. Therefore, this system defense technology has been actively researched. However, increasing the analysis complexity of the target system is limited in conventional NMTD because the variation of system properties (e.g., IP, port) that can be mutated... [more]

This paper proposes an innovative approach for controlling pollutant release in a long-distance tunnel via longitudinal ventilation. Enhanced by an active disturbance rejection control (ADRC) method, a ventilation controller is developed to regulate the forced air ventilation in a road tunnel. As a result, the pollutants (particulate matter and carbon monoxide) are reduced by actively regulating the air flow rate through the tunnel. The key contribution of this study lies in the development of an extended state observer that can track the system disturbance and provide the system with compensation via a nonlinear state feedback controller equipped by the ADRC. The proposed method enhances the disturbance attenuation capability in the ventilation system and keeps the pollutant concentration within the legitimate limit in the tunnel. In addition to providing a safe and clean environment for passengers, the improved tunnel ventilation can also achieve better energy saving as the air flow... [more]

Successful transitioning to a circular economy city requires a holistic and inclusive approach that involves bringing together diverse actors and disciplines who may not have shared aims and objectives. It is desirable that stakeholders work together to create jointly-held perceptions of value, and yet cooperation in such an environment is likely to prove difficult in practice. The contribution of this paper is to show how collaboration can be engendered, or discord made transparent, in resource decision-making using a hybrid Game Theory approach that combines its inherent strengths with those of scenario analysis and multi-criteria decision analysis. Such a methodology consists of six steps: (1) define stakeholders and objectives; (2) construct future scenarios for Municipal Solid Waste Management; (3) survey stakeholders to rank the evaluation indicators; (4) determine the weights for the scenarios criteria; (5) reveal the preference order of the scenarios; and (6) analyse the prefer... [more]

Organic Rankine Cycle (ORC) turbogenerators are a well-established technology to recover from medium to ultra-low grade heat and generate electricity, or heat and work as cogenerative units. High firmness, good reliability and acceptable efficiency guarantee to ORCs a large range of applications: from waste heat recovery of industrial processes to the enhancement of heat generated by renewable resources like biomass, solar or geothermal. ORC unit coupled with biomass boiler is one of the most adopted arrangements. However, despite biomass renewability, it is mandatory to evaluate the environmental impact of systems composed by boilers and ORCs taking into account the entire life cycle. To this purpose, the authors perform a life cycle assessment of a commercially available 150 kW cogenerative ORC unit coupled with a biomass boiler to assess the global environmental performance. The system is modelled in SimaPro using different approaches. Results show that the most impacting processes... [more]

Fire-induced thermal flow is the greatest threat to trapped people and the heat-resistant quality of building structures. This paper presents an experimental investigation of the effects of external wind on the ceiling temperature distribution of fire-induced thermal flow in a one-sixth scale corridor connected to a compartment. In the experiments, the fire source was placed in the compartment with hot thermal flow spilled into the connected corridor. The heat release rate (HRR) was changed from 10 to 20 kW and the external wind velocity was changed from 0 to 2.09 m/s. The ends of the corridor could be adjusted to be fully or partially open to the environment with dam-boards arranged at the ends of the corridor. An effective corridor HRR, Qcorridor, was defined to account for the amount of the spilled plume into the corridor. Results show that the temperature under the ceiling changed in a non-monotonic way with wind velocity: it first increased and then decreased with wind velocity. I... [more]

The first industrial-scale pyrolysis plant for solid tire wastes has been installed in Jenin, northern of the West Bank in Palestine, to dispose of the enormous solid tire wastes in the north of West Bank. The disposable process is an environmentally friendly process and it converts tires into useful products, which could reduce the fuel crisis in Palestine. The gravimetric analysis of tire waste pyrolysis products from the pyrolysis plant working at the optimum conditions is: tire pyrolysis oil (TPO): 45%, pyrolysis carbon black (PCB): 35%, pyrolysis gas (Pyro-Gas): 10% and steel wire: 10%. These results are depending on the tire type and size. It has been found that the produced pyrolysis oil has a High Heating Value (HHV), with a range of 42 − 43   ( MJ / kg ) , which could make it useful as a replacement for conventional liquid fuels. The main disadvantage of using the TPO as fuel is its strong acrid smell and its low flash point, as compared with the other conventi... [more]

To date, atmospheric concentrations of sulfur hexafluoride (SF6) are the most potent among the greenhouse gases identified by the Intergovernmental Panel on Climate Change (IPCC) and are still rising. In the EU-28, SF6 has been banned from several applications, however, an important exception is gas-insulated electrical switchgear (GIS) for which cost-effective and environmentally sound alternatives were unavailable when the F-Gas regulation was last revised in 2014. To date, after some recent innovations, we argue that the phasing out of SF6 could spur the accelerated development of alternatives with a lower carbon footprint. In the EU-28, the SF6 amount in switchgear is unclear. In this paper, we estimated the SF6 amount to be between 10,800 and 24,700 t (with a mode at 12,700 t) in 2017, resulting in 68 to 140 t of annual emissions from operational leakage only, corresponding to 1.6 to 3.3 Mt of CO2-eq. We additionally calculated the potential greenhouse gas savings over the lifecyc... [more]

The circular economy (CE), and its focus on the cycling and regeneration of resources, necessitates both a reconfiguration of existing infrastructures and the creation of new infrastructures to facilitate these flows. In urban settings, CE is being realized at multiple levels, from within individual organizations to across peri-urban landscapes. While most attention in CE research and practice focuses on organizations, the scale and impact of many such efforts are limited because they fail to account for the diversity of resources, needs, and power structures across cities, consequently missing opportunities for adopting a more effective and inclusive CE. Reconfiguring hard infrastructures is necessary for material resource cycling, but intervening in soft infrastructures is also needed to enable more inclusive decision-making processes to activate these flows. Utilizing participatory action research methods at the intersection of industrial ecology and design, we developed a new frame... [more]

Wood pellets could potentially contribute to bioenergy demand in the European Union (EU). Market cost constraints as well as greenhouse gas (GHG) emission savings thresholds imposed by the European Commission however limit the potential use of pellets. A spatially explicit assessment of import potentials of both pellets and torrefied pellets, based on the growing stock of forestry biomass in the US, Canada, Brazil, Russia and Baltic States, was combined with an analysis of supply chain costs and emissions in order to analyse potentials as limited by different levels of costs and emission constraints. Results show that in case of GHG savings thresholds of 70%, 80% and 85% the total import potential is reduced to 61 to 24 and 1 Mt, respectively. The potential for torrefied pellets is larger in all cases, 44 Mt in the case of an 80% limit. Import potentials at cost limits of 200, 175, 150 and 125 €/t are reduced from 58 Mt to 52, 38 and 9 Mt pellets, respectively, with little difference b... [more]