Editorial

3 pages, 168 KiB

Open AccessEditorial

by Alberto-Jesus Perea-Moreno and Francisco Manzano-Agugliaro

Energies 2020, 13(15), 3758; https://0-doi-org.brum.beds.ac.uk/10.3390/en13153758 - 22 Jul 2020

Cited by 3 | Viewed by 1411

The use of renewable energies, energy saving, and efficiency are needs of global society. According to the latest estimates, global energy demand could triple by 2050 and, by then, 70% of the world’s population will live in cities. Cities are currently responsible for [...] Read more.

The use of renewable energies, energy saving, and efficiency are needs of global society. According to the latest estimates, global energy demand could triple by 2050 and, by then, 70% of the world’s population will live in cities. Cities are currently responsible for 80% of greenhouse gas emissions, so they have a key role to play in shifting towards a sustainable energy future. Cities are threatened not only by overcrowding, but also by rising energy demand, obsolete infrastructure, volatile energy markets, and the effects of climate change. This Special Issue aims to advance the contribution of energy saving and the use of renewable energies in order to achieve more sustainable cities. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

Research

Jump to: Editorial

47 pages, 1314 KiB

Open AccessArticle

Factors That Contribute to Changes in Local or Municipal GHG Emissions: A Framework Derived from a Systematic Literature Review

by Isabel Azevedo and Vítor Leal

Energies 2020, 13(12), 3205; https://0-doi-org.brum.beds.ac.uk/10.3390/en13123205 - 19 Jun 2020

Cited by 4 | Viewed by 2066

Abstract

The changes observed in a municipal or local energy system over a period of time is due a number of concurrent dynamics such as the local social and economic trends, higher-level policies (e.g., national), and the local policies. Thus, a thorough identification and [...] Read more.

The changes observed in a municipal or local energy system over a period of time is due a number of concurrent dynamics such as the local social and economic trends, higher-level policies (e.g., national), and the local policies. Thus, a thorough identification and characterization of the many factors of change is key for an adequate assessment of the effectiveness of policies adopted at the local level, as well as for future planning. Such thorough identification and characterization of the factors that are determinant for the evolution of the local energy system is the content of this paper. The identification is performed through a systematic literature review, followed by a synthesis process. The factors identified are grouped into the categories of local context, local socio-economic and cultural evolution, higher-level governance framework, and local climate change mitigation actions. They are represented through a set of measurable variables. The factors and respective variables can be used to improve the disaggregation of changes in the local energy system into individual causes, leading to a better assessment of the evolution over time. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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13 pages, 1689 KiB

Open AccessArticle

Energy Recovery from Waste Tires Using Pyrolysis: Palestine as Case of Study

by Ramez Abdallah, Adel Juaidi, Mahmoud Assad, Tareq Salameh and Francisco Manzano-Agugliaro

Energies 2020, 13(7), 1817; https://0-doi-org.brum.beds.ac.uk/10.3390/en13071817 - 09 Apr 2020

Cited by 46 | Viewed by 6403

Abstract

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 [...] Read 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 conventional liquid fuels. The produced pyrolysis carbon black also has a High Heating Value (HHV) of about 29 (MJ/kg), which could also encourage its usage as a solid fuel. Carbon black could also be used as activated carbon, printers’ ink, etc. The pyrolysis gas (Pyro-Gas) obtained from waste tires mainly consist of light hydrocarbons. The concentration of H₂ has a range of 30% to 40% in volume and it has a high calorific value (approximately

31 MJ / m^{3}

), which can meet the process requirement of energy. On the other hand, it is necessary to clean gas before the burning process to remove H₂S from Pyro-Gas, and hence, reduce the acid rain problem. However, for the current plant, some recommendations should be followed for more comfortable operation and safer environment work conditions. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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29 pages, 6302 KiB

Open AccessArticle

Estimating the Optimum Tilt Angles for South-Facing Surfaces in Palestine

by Ramez Abdallah, Adel Juaidi, Salameh Abdel-Fattah and Francisco Manzano-Agugliaro

Energies 2020, 13(3), 623; https://0-doi-org.brum.beds.ac.uk/10.3390/en13030623 - 01 Feb 2020

Cited by 45 | Viewed by 6065

Abstract

The optimum tilt angle of solar panels or collectors is crucial when determining parameters that affect the performance of those panels. A mathematical model is used for determining the optimum tilt angle and for calculating the solar radiation on a south-facing surface on [...] Read more.

The optimum tilt angle of solar panels or collectors is crucial when determining parameters that affect the performance of those panels. A mathematical model is used for determining the optimum tilt angle and for calculating the solar radiation on a south-facing surface on a daily, monthly, seasonal, semi-annual, and annual basis. Photovoltaic Geographical Information System (PVGIS) and Photovoltaic Software (PVWatts) is developed by the NREL (US National Renewable Energy Laboratory) are also used to calculate the optimum monthly, seasonal, semi-annual, and annual tilt angles and to compare these results with the results obtained from the mathematical model. The results are very similar. PVGIS and PVWatts are used to estimate the solar radiation on south-facing surfaces with different tilt angles. A case study of a mono-crystalline module with 5 kWP of peak power is used to find out the amount of increased energy (gains) obtained by adjusting the Photovoltaic (PV) tilt angles based on yearly, semi-annual, seasonal, and monthly tilt angles. The results show that monthly adjustments of the solar panels in the main Palestinian cities can generate about 17% more solar energy than the case of solar panels fixed on a horizontal surface. Seasonal and semi-annual adjustments can generate about 15% more energy (i.e., it is worth changing the solar panels 12 times a year (monthly) or at least 2 times a year (semi-annually). The yearly optimum tilt angle for most Palestinian cities is about 29°, which yields an increase of about 10% energy gain compared to a solar panel fixed on a horizontal surface. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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21 pages, 9263 KiB

Open AccessArticle

Seasonal Wind Energy Characterization in the Gulf of Mexico

by Alberto-Jesus Perea-Moreno, Gerardo Alcalá and Quetzalcoatl Hernandez-Escobedo

Energies 2020, 13(1), 93; https://0-doi-org.brum.beds.ac.uk/10.3390/en13010093 - 23 Dec 2019

Cited by 16 | Viewed by 2891

Abstract

In line with Mexico’s interest in determining its wind resources, in this paper, 141 locations along the states of the Gulf of Mexico have been analyzed by calculating the main wind characteristics, such as the Weibull shape (c) and scale ( [...] Read more.

In line with Mexico’s interest in determining its wind resources, in this paper, 141 locations along the states of the Gulf of Mexico have been analyzed by calculating the main wind characteristics, such as the Weibull shape (c) and scale (k) parameters, and wind power density (WPD), by using re-analysis MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications version 2) data with hourly records from 1980–2017 at a 50-m height. The analysis has been carried out using the R free software, whose its principal function is for statistical computing and graphics, to characterize the wind speed and determine its annual and seasonal (spring, summer, autumn, and winter) behavior for each state. As a result, the analysis determined two different wind seasons along the Gulf of Mexico;, it was found that in the states of Tamaulipas, Veracruz, and Tabasco wind season took place during autumn, winter, and spring, while for the states of Campeche and Yucatan, the only two states that shared its coast with the Caribbean Sea and the Gulf of Mexico, the wind season occurred only in winter and spring. In addition, it was found that by considering a seasonal analysis, more accurate information on wind characteristics could be generated; thus, by applying the Weibull distribution function, optimal zones for determining wind as a resource of energy can be established. Furthermore, a k-means algorithm was applied to the wind data, obtaining three clusters that can be seen by month; these results and using the Weibull parameter c allow for selecting the optimum wind turbine based on its power coefficient or efficiency. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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18 pages, 392 KiB

Open AccessArticle

A Rebalancing Strategy for the Imbalance Problem in Bike-Sharing Systems

by Peiyu Yi, Feihu Huang and Jian Peng

Energies 2019, 12(13), 2578; https://0-doi-org.brum.beds.ac.uk/10.3390/en12132578 - 04 Jul 2019

Cited by 23 | Viewed by 3350

Abstract

Shared bikes have become popular traveling tools in our daily life. The successful operation of bike sharing systems (BSS) can greatly promote energy saving in a city. In BSS, stations becoming empty or full is the main cause of customers failing to rent [...] Read more.

Shared bikes have become popular traveling tools in our daily life. The successful operation of bike sharing systems (BSS) can greatly promote energy saving in a city. In BSS, stations becoming empty or full is the main cause of customers failing to rent or return bikes. Some truck-based rebalancing strategies are proposed to solve this problem. However, there are still challenges around the relocation of bikes. The truck operating costs also need to be considered. In this paper, we propose a customer-oriented rebalancing strategy to solve this problem. In our strategy, two algorithms are proposed to ensure the whole system is balanced for as long as possible. The first algorithm calculates the optimal state of each station through the one-dimensional Random Walk Process with two absorption walls. Based on the derived optimal state of each station, the second algorithm recommends the station that has the largest difference between its current state and its optimal state to the customer. In addition, a simulation system of shared bikes based on the historical records of Bay Area Bikeshare is built to evaluate the performance of our proposed rebalancing strategy. The simulation results indicate that the proposed strategy is able to effectively decrease the imbalance in the system and increase the system’s performance compared with the truck-based methods. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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22 pages, 6734 KiB

Open AccessArticle

Wind Power Cogeneration to Reduce Peak Electricity Demand in Mexican States Along the Gulf of Mexico

by Quetzalcoatl Hernandez-Escobedo, Javier Garrido, Fernando Rueda-Martinez, Gerardo Alcalá and Alberto-Jesus Perea-Moreno

Energies 2019, 12(12), 2330; https://0-doi-org.brum.beds.ac.uk/10.3390/en12122330 - 18 Jun 2019

Cited by 2 | Viewed by 2921

Abstract

The Energetic Transition Law in Mexico has established that in the next years, the country has to produce at least 35% of its energy from clean sources in 2024. Based on this, a proposal in this study is the cogeneration between the principal [...] Read more.

The Energetic Transition Law in Mexico has established that in the next years, the country has to produce at least 35% of its energy from clean sources in 2024. Based on this, a proposal in this study is the cogeneration between the principal thermal power plants along the Mexican states of the Gulf of Mexico with modeled wind farms near to these thermal plants with the objective to reduce peak electricity demand. These microscale models were done with hourly MERRA-2 data that included wind speed, wind direction, temperature, and atmospheric pressure with records from 1980–2018 and taking into account roughness, orography, and climatology of the site. Wind speed daily profile for each model was compared to electricity demand trajectory, and it was seen that wind speed has a peak at the same time. The amount of power delivered to the electric grid with this cogeneration in Rio Bravo and Altamira (Northeast region) is 2657.02 MW and for Tuxpan and Dos Bocas from the Eastern region is 3196.18 MW. This implies a reduction at the peak demand. In the Northeast region, the power demand at the peak is 8000 MW, and for Eastern region 7200 MW. If wind farms and thermal power plants work at the same time in Northeast and Eastern regions, the amount of power delivered by other sources of energy at this moment will be 5342.98 MW and 4003.82 MW, respectively. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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23 pages, 3768 KiB

Open AccessArticle

Analysis of Research Topics and Scientific Collaborations in Energy Saving Using Bibliometric Techniques and Community Detection

by Carmen de la Cruz-Lovera, Alberto-Jesus Perea-Moreno, José Luis de la Cruz-Fernández, Francisco G. Montoya, Alfredo Alcayde and Francisco Manzano-Agugliaro

Energies 2019, 12(10), 2030; https://0-doi-org.brum.beds.ac.uk/10.3390/en12102030 - 27 May 2019

Cited by 18 | Viewed by 3868

Abstract

Concern about everything related to energy is increasingly latent in the world and therefore the use of energy saving concepts has been increasing over the past several years. The interest in the subject has allowed a conceptual evolution in the scientific community regarding [...] Read more.

Concern about everything related to energy is increasingly latent in the world and therefore the use of energy saving concepts has been increasing over the past several years. The interest in the subject has allowed a conceptual evolution in the scientific community regarding the understanding of the adequate use of energy. The objective of this work is to determine the contribution made by international institutions to the specialized publications in the area of energy-saving from 1939 to 2018, using Scopus Database API Interface. The methodology followed in this research was to perform a bibliometric analysis of the whole scientific production indexed in Scopus. The world’s scientific production has been analysed in the following domains: First the trend over time, types of publications and countries, second, the main subjects and keywords, third, main institutions and their main topics, and fourth, the main journals and proceedings that publish on this topic. Then, these data are presented using community detection algorithms and graph visualization software. With these techniques, it is possible to determine the main areas of research activity as well as to identify the structures of the collaboration network in the field of renewable energy. The results of the work show that the literature in this field have substantially increased during the last 10 years. Full article

(This article belongs to the Special Issue Energy Saving at Cities)

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