Energy, which is the main agenda of our world, is crucially important for the people. Many countries frequently held meetings and discussions with energy agenda. These countries are working to balance the energy demand and supply. For finding the solution are researched, researches should be attempted to present a more efficient way to use energy as well as renewable energy resources effectively. Photovoltaic energy power systems take place as the most dominant source among renewable energy technologies. The most important reason is that it is unlimited and clean energy of the solar power systems. Many studies show that photovoltaic power systems will have an important share in the electricity of the future. In this study, to generate electricity from solar energy using photovoltaic systems have a leading position in some European countries, United States of America, China and Japan's current status and future policies will be analyzed in various comments were made.

The analysis on photovoltaic electricity generation status, potential and policies of the leading countries in solar energy

Quantifying rooftop photovoltaic solar energy potential: A machine learning approach

Estimation of rooftop solar photovoltaic potential of a city

Development of a method for estimating the rooftop solar photovoltaic (PV) potential by analyzing the available rooftop area using Hillshade analysis

The transition to renewable energies will intensify the global competition for land. Nevertheless, most analyses to date have concluded that land will not pose significant constraints on this transition. Here, we estimate the land-use requirements to supply all currently consumed electricity and final energy with domestic solar energy for 40 countries considering two key issues that are usually not taken into account: (1) the need to cope with the variability of the solar resource, and (2) the real land occupation of solar technologies. We focus on solar since it has the highest power density and biophysical potential among renewables. The exercise performed shows that for many advanced capitalist economies the land requirements to cover their current electricity consumption would be substantial, the situation being especially challenging for those located in northern latitudes with high population densities and high electricity consumption per capita. Assessing the implications in terms of land availability (i.e., land not already used for human activities), the list of vulnerable countries enlarges substantially (the EU-27 requiring around 50% of its available land), few advanced capitalist economies requiring low shares of the estimated available land. Replication of the exercise to explore the land-use requirements associated with a transition to a 100% solar powered economy indicates this transition may be physically unfeasible for countries such as Japan and most of the EU-27 member states. Their vulnerability is aggravated when accounting for the electricity and final energy footprint, i.e., the net embodied energy in international trade. If current dynamics continue, emerging countries such as India might reach a similar situation in the future. Overall, our results indicate that the transition to renewable energies maintaining the current levels of energy consumption has the potential to create new vulnerabilities and/or reinforce existing ones in terms of energy and food security and biodiversity conservation.

/pdf/assessing-vulnerabilities-and-limits-in-the-transition-to-57oplgdrba.pdf

Assessing vulnerabilities and limits in the transition to renewable energies: Land requirements under 100% solar energy scenarios

Fossil fuel energy resources are becoming increasingly scarce. Given the negative environmental impacts (e.g. greenhouse gas emissions) that accompany their use, it is hardly surprising that the development of renewable energies has become a major priority in the world today. Andalusia, with a mean solar radiation of 4.75 kWh/m 2 per day and a surface area of 87,597 km 2 , is the region in Europe with the highest solar energy potential. This research study determined the solar energy potential in Andalusia for grid-connected photovoltaic systems installed on residential rooftops. A methodology was developed for this purpose, which first involved a description of building characteristics, followed by the calculation of the useful roof surface area where photovoltaic arrays could be installed. In the next phase of the study, the mean solar irradiation characteristics were defined as well as the technical parameters of the photovoltaic systems. All of these factors allowed us to estimate the amount of electricity that could be potentially generated per year by solar panels.

Analysis of the photovoltaic solar energy capacity of residential rooftops in Andalusia (Spain)

Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled aggregates were compared. Different specimens of unbound recycled mixtures demonstrated increased resistance properties. The formation of new cement hydrated particles was observed, and pozzolanic reactions were discovered by electronon microscopy in these novel materials. The properties of recycled concrete aggregates and mixed recycled aggregates suggest that these recycled materials can be used in unbound road layers to improve their mechanical behaviour in the long term.

https://www.mdpi.com/1996-1944/8/12/5493/pdf

Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base

Crushing treatment on recycled aggregates to improve their mechanical behaviour for use in unbound road layers

Rising detrimental global environmental statistics and measurable effects have caused the sustainable building concept to gain momentum. As a result, many sustainable building rating systems and as...

Sustainable building rating systems: A critical review for achieving a common consensus

The management of different industrial by-products, such as recycled aggregates from construction and demolition waste and alumina by-products, as well as the reduction of landfill deposits by incorporating these products in a second life cycle, were the focus of this work. The aim of this study was to demonstrate the technical viability of using these waste and by-product as a material for road pavement base layers. For this purpose, a real-scale application was carried out, and the behavior of three types of materials, applied on a section of an experimental road under real vehicle traffic conditions, was studied and compared. Three materials were used in these sections applied in the road sub-bases. First, a control material composed of a type of artificial gravel was used to be compared with the rest of materials; the second material was composed of recycled aggregates, and the third was composed of a mix of recycled aggregates and alumina waste. The results concluded that the effectiveness of the sections built using recycled aggregates and alumina waste was very positive and similar those constructed using natural aggregates.

https://www.mdpi.com/1996-1944/14/6/1466/pdf

Javier Alegre

Papers

Analysis of the photovoltaic solar energy capacity of residential rooftops in Andalusia (Spain)

Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base

Crushing treatment on recycled aggregates to improve their mechanical behaviour for use in unbound road layers

Sustainable building rating systems: A critical review for achieving a common consensus

Feasible Use of Recycled Concrete Aggregates with Alumina Waste in Road Construction.