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Energy Efficiency Assessments and Improvements

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A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "C: Energy Economics and Policy".

Deadline for manuscript submissions: closed (31 March 2024) | Viewed by 9698

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Special Issue Editors

Dr. Inga Konstantinaviciute

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Laboratory of Energy Systems Research, Lithuanian Energy Institute, Breslaujos Str. 3, LT-44403 Kaunas, Lithuania
Interests: long-term nergy demand forecasting; energy sector planning; analysis of energy efficiency indicators; environmental issues of energy sector; analysis of renewable energy and energy efficiency policies; energy sufficiency; GHG emissions inventory and projections for energy sector
Special Issues, Collections and Topics in MDPI journals

Dr. Viktorija Bobinaite

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Laboratory of Energy Systems Research, Lithuanian Energy Institute, Breslaujos Str. 3, LT-44403 Kaunas, Lithuania
Interests: electricity price forecasting; market design; policies and measures for energy efficiency; renewable energy and energy sufficiency; policy assessment

Prof. Dr. Vaclovas Miškinis

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Guest Editor

Laboratory of Energy Systems Research, Lithuanian Energy Institute, Breslaujos Str. 3, LT-44403 Kaunas, Lithuania
Interests: analysis of energy balances; long-term energy demand forecasting; energy sector planning; energy effciency assessment; energy policy

Prof. Dr. Saulius Gudžius

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Guest Editor

Department of Electric Power Systems, Faculty of Electrical and Electronics Engineering, Kaunas University of Technology, Studentu Str. 48, LT-51367 Kaunas, Lithuania
Interests: optimization of power systems modelling; renewable energy integration; energy storage; power generation planning; energy effciency assessment

Prof. Dr. Daiva Dumciuviene

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School of Economics and Business, Kaunas University of Technology, Gedimino Str. 50, LT-51367 Kaunas, Lithuania
Interests: sustainable economics; energy economics; assessment of energy efficiency; analysis of energy efficiency indicators; energy consumer behaviour
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The goal of commitment to net-zero GHG emissions by 2050 is an important agenda to overcome the global crisis of climate change. Energy efficiency is a vital component in achieving carbon neutrality through decarbonization. It is also recognized as one of the easiest and the most cost-effective ways to combat air pollution, reduce energy costs, and improve the competitiveness and productivity of economies.

We hope that this Special Issue will contribute to the identification of opportunities and challenges of energy efficiency assessment as well as methods for its improvements. This Special Issue aims to present and disseminate the most recent advances related to the theory, monitoring, assessment, improvement and modeling of energy efficiency and the energy efficiency policy.

Topics of interest for publication include, but are not limited to:

Energy efficiency assessment in all economic sectors;
Energy efficiency improvements;
Energy efficiency indicators;
Energy efficiency policies, impacts and their interactions;
Energy efficiency economics;
Multiple benefits of energy efficiency;
Socio-economic and environmental co-benefits of energy efficiency.

Dr. Inga Konstantinaviciute
Dr. Viktorija Bobinaite
Prof. Dr. Vaclovas Miškinis
Prof. Dr. Saulius Gudžius
Prof. Dr. Daiva Dumciuviene
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

energy efficiency assessment
energy efficiency improvement
energy efficiency policy
indicators
modelling
energy management
energy economics
socio-economics
environment
multiple benefit

Published Papers (9 papers)

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Research

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19 pages, 2087 KiB

Open AccessArticle

Assessment of Grid and System Supportability Based on Spatio-Temporal Conditions—Novel Key Performance Indicators for Energy System Evaluation

by Heiko Waurisch, Nick von Bargen, Nico Ploczicki, Bente Ralfs, Berit Elsner, Reiner Schütt and Nassipkul Dyussembekova

Energies 2024, 17(7), 1534; https://doi.org/10.3390/en17071534 - 23 Mar 2024

Viewed by 542

Abstract

The energy transition introduces new technical standards, laws and regulations regarding the stability and reliability of energy grids and systems. Due to the non-existence of a measuring standard, key performance indicators (KPIs) were developed to enable the measurement and comparison of individual energy grid (namely electricity, heat and gas grid) and system supportabilities while also promoting well-founded decision-making and optimization efforts. Inconsistencies in definitions concerning fundamental energy terms and the correlations between them inhibit the effective usage of the KPIs. Therefore, the overarching issue of the security of energy supply and its related subjects were also approached. The primary subject of this paper is the development of two new KPIs to measure and compare the energy grid and system supportability. These KPIs are based on spatio-temporal conditions in their respective grids. The usage and benefits of the developed KPIs are exemplarily highlighted by analyzing the impact of a scenario with the integration of a large-scale heat pump into the electricity and heat grid. The energy grid supportability is determined for each grid, whereas the energy system supportability takes the interactions of the electricity and heat grid into account. The developed KPIs are intended to enable stakeholders to identify areas with optimization potential in energy grids and systems. Moreover, the KPIs can be used to create a standardized evaluation method for regulatory requirements. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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22 pages, 3752 KiB

Open AccessArticle

Key Performance Indicators for Decision Support in Building Retrofit Planning: An Italian Case Study

by Ilaria Abbà, Giulia Crespi, Giulia Vergerio, Cristina Becchio and Stefano Paolo Corgnati

Energies 2024, 17(3), 559; https://doi.org/10.3390/en17030559 - 24 Jan 2024

Viewed by 600

Abstract

To achieve climate and energy goals in the building sector, the current pace of renovating existing structures must double, overcoming prevailing barriers. Key Performance Indicators play a pivotal role in science-based decision making, emphasizing both direct and indirect benefits of building retrofits. The authors aim to contribute to proper metric identification for multi-perspective building performance assessment and formulate a methodology supporting energy planning decisions. They introduce the Global Cost per Emission Savings (GCES), an aggregated indicator encompassing both public (CO₂ emissions) and private (global cost) perspectives of diverse retrofit technologies for building HVAC systems. Applied to the Italian residential building stock via the Reference Building approach, the methodology is tested using condensing gas boilers, biomass boilers, and electric heat pumps, revealing diverse environmental and economic performances. Addressing the establishment of effective decision-support tools for policymakers, the paper explores the potential impact of various policies on the favorability of technologies. Different policy scenarios are delineated to analyze how distinct approaches may influence the attractiveness of technologies. Notably, in the baseline scenario, biomass boilers hold an advantage over heat pumps according to the GCES index. However, scenarios involving technology-specific incentives or a greenhouse gases emission tax failed to alter the technological ranking, leaving heat pumps financially uncompetitive. In contrast, the TXPM scenario positions heat pumps as the most financially appealing option, penalizing biomass boilers for high particulate matter emissions. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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20 pages, 7606 KiB

Open AccessArticle

Comprehensive Numerical Analysis of a Four-Way Two-Position (4/2) High-Frequency Switching Digital Hydraulic Valve Driven by a Ring Stack Actuator

by Paolo Tamburrano, Francesco Sciatti, Elia Distaso and Riccardo Amirante

Energies 2023, 16(21), 7355; https://doi.org/10.3390/en16217355 - 31 Oct 2023

Cited by 1 | Viewed by 956

Abstract

This paper presents a feasibility study using a commercially available ring stack actuator to develop a four way-two position (4/2) high frequency switching digital hydraulic valve. The excellent characteristics of multilayer piezoelectric actuators, such as a simple design, reduced moving parts, high reliability, and fast response, make them ideal for constructing this type of digital hydraulic valve. High frequency switching digital hydraulic valves (HFSVs), indeed, must be able to switch from fully open to fully closed positions in less than 5 ms, while maintaining minimal pressure losses and delivering large flows. The proposed valve architecture is assessed using well-established equations implemented in a Simulink model, allowing the hydraulic, mechanical, and electrical parts of the valve to be accurately simulated. The paper first provides a detailed description of the numerical model. Next, the hysteresis model of the ring stack actuator is validated against the data provided by the manufacturers on their website. Finally, the numerical results obtained with both open-loop and closed-loop control systems are presented. The simulations show that at a switching frequency of 200 Hz with maximum amplitude and duty cycle of the input pulse digital signal, the valve exhibits high average flow rates (~60 L/min), low average power consumption (~1500 W), and maintains a pressure drop of only 15 bar. Moreover, the simulations reveal that the control system is very effective since the valve switching time is within 1 ms. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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17 pages, 7927 KiB

Open AccessArticle

Detailed Energy Analysis of a Sheet-Metal-Forming Press from Electrical Measurements

by Camilo Carrillo, Eloy Díaz Dorado, José Cidrás Pidre, Julio Garrido Campos, Diego San Facundo López, Luiz A. Lisboa Cardoso, Cristina I. Martínez Castañeda and José F. Sánchez Rúa

Energies 2023, 16(19), 6972; https://doi.org/10.3390/en16196972 - 06 Oct 2023

Viewed by 792

Abstract

This paper presents a methodology that allows for the detection of the state of a sheet-metal-forming press, the parts being produced, their cadence, and the energy demand for each unit produced. For this purpose, only electrical measurements are used. The proposed analysis is conducted at the level of the press subsystems: main motor, transfer module, cushion, and auxiliary systems, and is intended to count, classify, and monitor the production of pressed parts. The power data are collected every 20 ms and show cyclic behavior, which is the basis for the presented methodology. A neural network (NN) based on heuristic rules is developed to estimate the press states. Then, the production period is determined from the power data using a least squares method to obtain normalized harmonic coefficients. These are the basis for a second NN dedicated to identifying the parts in production. The global error in estimating the parts being produced is under 1%. The resulting information could be handy in determining relevant information regarding the press behavior, such as energy per part, which is necessary in order to evaluate the energy performance of the press under different production conditions. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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17 pages, 2159 KiB

Open AccessArticle

Changing Electricity Tariff—An Empirical Analysis Based on Commercial Customers’ Data from Poland

by Tomasz Ząbkowski, Krzysztof Gajowniczek, Grzegorz Matejko, Jacek Brożyna, Grzegorz Mentel, Małgorzata Charytanowicz, Jolanta Jarnicka, Anna Olwert and Weronika Radziszewska

Energies 2023, 16(19), 6853; https://doi.org/10.3390/en16196853 - 27 Sep 2023

Cited by 1 | Viewed by 737

Abstract

Nearly 60% of commercial customers are connected to a low-voltage network in Poland with a contractual capacity of more than 40 kW and are assigned a fixed tariff with flat prices for the whole year, no matter the usage volume. With smart meters, more data about how businesses use energy are becoming available to both energy providers and customers. This enables innovation in the structure and type of tariffs on offer in the energy market. Customers can explore their usage patterns to choose the most suitable tariff to benefit from lower prices and thus generate savings. In this paper, we analyzed whether customers’ electricity usage matched their optimal tariff and further investigated which of them could benefit or lose from switching the tariff based on the real dataset with the hourly energy readings of 1212 commercial entities in Poland recorded between 2016 and 2019. Three modelling approaches, i.e., the k-nearest neighbors, classification tree and random forest, were tested for optimal tariff classification, while for the benchmark, we used a simple approach, in which the tariff was proposed based on the customers’ previous electricity usage. The main findings from the research are threefold: (1) out of all the analyzed entities, on average, 76% of them could have benefited from the tariff switching, which suggests that customers may not be aware of the tariff change benefits, or they had chosen a tariff plan that was not tailored to them; (2) a random forest model offers a viable approach to accurate tariff classification; (3) the policy implication from the research is the need to increase the customers’ awareness about the tariffs and propose reliable tools for selecting the optimal tariff. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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29 pages, 3454 KiB

Open AccessArticle

Assessment of Technical and Economic Potential of Urban Rooftop Solar Photovoltaic Systems in Lithuania

by Paulius Kozlovas, Saulius Gudzius, Jokubas Ciurlionis, Audrius Jonaitis, Inga Konstantinaviciute and Viktorija Bobinaite

Energies 2023, 16(14), 5410; https://doi.org/10.3390/en16145410 - 16 Jul 2023

Cited by 3 | Viewed by 1256

Abstract

This paper aimed at assessing the technical and economic potential of using rooftop solar photovoltaic (PV) systems in Lithuanian urban areas to support energy and climate policy formation and its implementation in the country. A bottom-up approach was applied. A number of apartment (AP), commercial (COM) and public (PUB) buildings, electric vehicle (EV) charging infrastructures and solar PV systems in the largest Lithuanian cities were analyzed, and the results were tailored to national-wide estimates. LiDAR and photogrammetry data of building topologies, geographical information systems (GIS), digital maps for rooftop measurements, factual solar photovoltaic (PV) performance modeling, average profiles of solar PV systems, statistical data of energy consumption in buildings, levelized cost of energy (LCOE) models and the literature review method were used. The results of the assessment of selected buildings and their categories reveal that the rooftop area per installed PV unit was 14.1–18.3 m²/kW in AP buildings, followed by 18.0–18.6 m²/kW in COM and 6.1–18.3 m²/kW in PUB buildings; the factor of rooftop suitability for solar PV system installation varied in ranges of 31.5–85.4%, 48.9–99.4% and 50.1–88.2%, respectively. Corrected by expert judgement, these estimates served as inputs for the assessment of technical and economic potentials. Furthermore, energy generated by solar PV could be consumed locally with little supplied to the distribution grid, resulting in no or a limited need for expensive investments in infrastructure. In addition, locating an EV charger on the premises of COM or PUB buildings could improve the localized consumption of solar energy. Thus, rooftop solar PV systems in urban Lithuanian areas are preferable. The results of the technical potential analysis show that, on the rooftops of AP buildings, 272 MW could be installed, followed by 78 MW on roofs of PUB and 67 MW on COM buildings. If technical potential is extracted, EUR 332.7 million can be invested. The cost of energy produced by solar PV systems was estimated at 2.34–5.25 EURct/kWh, which is significantly lower than the prices of market and retail electricity, standing at 23 EURct/kWh and 24 EURct/kWh (with support from the government) in 2022, respectively. The research’s limitations are defined by the fact that average values were applied to estimate the technical and economic potential of rooftop solar PV systems; a limited number of building categories were analyzed; the category of private houses, which is minor in cities, was missed, and rural areas with a great number of private houses were not covered by this study. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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20 pages, 1435 KiB

Open AccessArticle

Relationships between Selected Quality Tools and Energy Efficiency in Production Processes

by Marta Daroń and Monika Górska

Energies 2023, 16(13), 4901; https://doi.org/10.3390/en16134901 - 23 Jun 2023

Viewed by 942

Abstract

European manufacturing companies are currently in a very difficult situation. On the one hand, they have to strive for sustainable development. On the other hand, they have to face problems related to the geopolitical situation and the pursuit of cleaner production (including restrictive regulations on emissions). A significant increase in electricity prices means that companies have to take steps to use electricity rationally without reducing the level of production or incurring other additional costs. In this study, attention was paid to the influence of quality tools (QTs) in production process (PP) management on increasing energy efficiency (EE). Based on the literature review, it was found that the most frequently described QTs, i.e., SMED, TPM, Six Sigma, SPC, FMEA, 5S, or Poka-Yoke, used to improve PP did not take into account their impact on the EE of the enterprises. Therefore, the main purpose of this study was to examine this correlation and show that QTs can be helpful in shaping the energy management system (EMS). Achieving the research goal was possible thanks to surveys carried out among manufacturing companies. Using statistical tests, the existence of a statistically significant correlation was proved between QTs and EMS elements. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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16 pages, 3027 KiB

Open AccessArticle

Effects of Coupling Combined Heat and Power Production with District Cooling

by Kertu Lepiksaar, Vladislav Mašatin, Igor Krupenski and Anna Volkova

Energies 2023, 16(12), 4552; https://doi.org/10.3390/en16124552 - 06 Jun 2023

Cited by 2 | Viewed by 1013

Abstract

Over the past decades, combined heat and power production (CHP) has proven itself to be an efficient means of meeting both heat and power demands. However, high efficiency can be achieved with CHP plants when the heat load is sufficient, while lower-priority CHP plants must deal with the excess heat associated with power generation. This excess heat can be used for district cooling with absorption chillers. Although the absorption chiller is an efficient technology for using excess heat for cooling generation, its efficiency is very sensitive to driving hot water temperature. This paper provides a detailed analysis of how cooling generation in CHP plants using absorption chillers affects power generation and primary energy consumption. This study is based on the operational parameters of the Mustamäe CHP plant (Tallinn, Estonia) and the cooling demand of the Tehnopol science and business campus and proposes a sufficient cooling production capacity based on the estimation of the campus’ cooling demand. Additional cooling production opportunities to meet district cooling demand are discussed and compared in this paper in terms of primary energy savings and economic profit. The study finds that for the effective use of CHP excess heat and efficient cooling production, the use of an 0.8 MW absorption cooler and 11.6 MW heat pumps is recommended. This system would use 1.9 times less primary energy for cooling generation than local cooling. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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Review

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36 pages, 4594 KiB

Open AccessReview

Energy Management Systems in Sustainable Smart Cities Based on the Internet of Energy: A Technical Review

by Priyanka Mishra and Ghanshyam Singh

Energies 2023, 16(19), 6903; https://doi.org/10.3390/en16196903 - 30 Sep 2023

Cited by 10 | Viewed by 1867

Abstract

In this paper, we exploit state-of-the-art energy management in sustainable smart cities employing the Internet of Energy (IoE). The primary goal of this study is to leverage cutting-edge energy management techniques through the IoE in sustainable smart cities to bring about significant improvements in clean energy processes while targeting environmental benefits, efficiency enhancements, sustainability, and cost reduction. In this work, we present a comprehensive exploration of energy management strategies within the context of IoE-enabled sustainable smart cities. Firstly, we provide a detailed classification of diverse energy management approaches pertinent to IoE-based sustainable smart cities. This classification covers a spectrum of methodologies, including scheduling optimization, the design of low-power device transceivers, cognitive frameworks, and the integration of cloud computing technology. Furthermore, we highlight the pivotal role of smart grids as fundamental elements in the establishment of smart cities. Within this context, we offer a comprehensive overview of the essential components that underlie smart grids, with a notable focus on the intricate realm of micro/nanogrids. Moreover, our research delves comprehensively into energy harvesting within the context of smart cities. We analyze crucial facets like receiver design, energy optimization methods, a variety of energy sources, efficient energy scheduling approaches, and the establishment of effective energy routing mechanisms. Additionally, we delve into the multifaceted nature of sustainable smart cities across various domains. Our investigation reaches its culmination in the creation of a novel conceptual framework and the identification of enabling technologies centered on effective energy management. Lastly, we contribute to the field by outlining the current research challenges and mapping potential research directions relevant to energy management within sustainable smart cities, capitalizing on the capabilities of the IoT. Full article

(This article belongs to the Special Issue Energy Efficiency Assessments and Improvements)

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