Scalable methodology for the photovoltaic solar energy potential assessment based on available roof surface area: Further improvements by ortho-image analysis and application to Turin (Italy)

The ongoing rush of the UE member states to the 2020 overall targets on the national renewable energy share (see Directive 2009/28/EC), is propelling the large exploitation of the solar resource for the electricity production. However, the incentives to the large employment of PV solar modules and the relative perspective profits, are often cause of massive ground-mounted installations. These kind of installations are obviously the preferred solution by the investors for their high economic yields, but their social impact should be also considered. Over the Piedmont Region for instance, the large proliferation of PV farms is jeopardising wide agricultural terrains and turistic areas, therefore the policy of the actual administration is to encourage the use of integrated systems in place of massive installations. For these reasons, an effort to demonstrate that the distributed residential generation can play a primary role in the market is mandatory. In our previous work “Scalable methodology for the photovoltaic solar energy potential assessment based on available roof surface area: application to Piedmont Region (Italy)”, we already proposed a basic methodology for the evaluation of the roof-top PV system potential. However, despite the total roof surface has been computed on a given cartographical dataset, the real roof surface available for PV installations has been evaluated through the assumption of representative roofing typologies and empirical coefficients found via visual inspection of satellite images. In order to overcome this arbitrariness and refine our methodology, in the present paper we present a brand new algorithm to compute the available roof surface, based on the systematical analysis and processing of aerial georeferenced images (ortho-images). The algorithm, fully developed in MATLAB®, accounts for shadow, roof surface available (bright and not), roof features (i.e. chimneys or walls) and azimuthal angle of the eventual installation. Here we apply the algorithm to the whole city of Turin, and process more than 60,000 buildings. The results achieved are finally compared with our previous work and the updated PV potential assessment is consequently discussed.     

Estimating photovoltaic energy potential from a minimal set of randomly sampled data

The remarkable rise of photovoltaics in the world over the past years testifies of the great improvement in the use of solar energy. Opportunities for further new PV installations are being sought, especially power plants in areas with as yet little exploited solar energy potential. In this paper, we describe a methodology for generating estimation models of PV electricity for installations in large regions where only a few scattered data or measurement stations are available. For validation only, application of this methodology was performed considering Italy, where estimations can be benchmarked using the Photovoltaic Geographical Information System (PVGIS) by the Joint Research Centre of the European Commission. The results show that the mean absolute errors were usually lower than 4%, compared to the PVGIS data, for about 90% of the estimates of PV electricity, and about 6% for the greatest mean error.     

GIS-based approach for potential analysis of solar PV generation at the regional scale: A case study of Fujian Province

Spatial variation of solar energy is crucial for the estimation of the regional potential and selection of construction location. This paper presents a case study of using high resolution grid map of solar radiation combined with the other restriction factors to evaluate the comprehensive potential analysis of solar PV generation at the regional scale, in order to present a framework of decision support tool for solar energy management in a regional area. The cost of PV generation is calculated based on the geographical distribution of technical potential. Moreover, geospatial supply curve (GSC) is employed to portray the evolution of available potential of photovoltaics (PV) generation with the increase of the generation cost. By integrating the economic evaluation variables of net present value and simple payback period, grid-based economic feasibility of PV generation project is then carried out under two feed-in-tariff scenarios. Finally, total CO₂ reduction potential and its spatial distribution in the study area are calculated. The results confirm that PV technology provides high potential for roof-top application and large-scale PV stations. Additionally, determining a reasonable feed-in tariff is essential for expanding the application of solar PV energy. The findings improve understanding of regional renewable energy strategies and the supply/demand assessment.     

Means of enhancing and promoting the use of solar energy

The development of renewable technologies in the last decade has been exceptional. In photovoltaic (PV) for example, efforts were not only limited to merely improving their efficiency but also to the reduction of the cost of cells and modules via volume production for commercial markets. There are many national schemes promoting the use of PV technology and regional targets for a share of renewable energy production. This paper attempts to relay to the reader a journey, based on experience, approaches for enhancing the prospect of utilising solar energy within the society we live in. The issue of expansion or enhancing the utilisation of solar energy can be undertaken by individuals, groups, institutions and governments. The aim of this paper is to provide some examples, which could serve as a framework in which action could be taken to promote solar technology.     

Electricity produced from renewable energy sources—What target are we aiming for?

In 2001, the European Commission (hereafter “EC”) formulated an ambitious target of 21% of total community electricity consumption to be generated with renewable energy sources by 2010. Moreover, national indicative targets per Member State were specified. In practice, the latter are implemented in all Member States as national production targets, achievable exclusively through an increase of the domestic production of electricity produced from renewable energy sources (hereafter “RES-E”). However, in this article it will be shown that this is not in line with the EC's intent. Looking at the legislative process resulting in the Directive on the promotion of RES-E, it is demonstrated that instead the EC aimed for European trade in renewable electricity through national consumption targets.     

Potential of solar electricity generation in the European Union member states and candidate countries

During the years 2001–2005, a European solar radiation database was developed using a solar radiation model and climatic data integrated within the Photovoltaic Geographic Information System (PVGIS). The database, with a resolution of 1 km × 1 km, consists of monthly and yearly averages of global irradiation and related climatic parameters, representing the period 1981–1990. The database has been used to analyse regional and national differences of solar energy resource and to assess the photovoltaic (PV) potential in the 25 European Union member states and 5 candidate countries. The calculation of electricity generation potential by contemporary PV technology is a basic step in analysing scenarios for the future energy supply and for a rational implementation of legal and financial frameworks to support the developing industrial production of PV. Three aspects are explored within this paper: (1) the expected average annual electricity generation of a ‘standard’ 1 kW_p grid-connected PV system; (2) the theoretical potential of PV electricity generation; (3) determination of required installed capacity for each country to supply 1% of the national electricity consumption from PV. The analysis shows that PV can already provide a significant contribution to a mixed renewable energy portfolio in the present and future European Union.     

Estimation of rooftop solar photovoltaic potential using geo-spatial techniques: A perspective from planned neighborhood of Karachi – Pakistan

With an ever increasing population and significant solar resource availability throughout the whole year, Karachi metropolis hold a promising rooftop solar photovoltaic (PV) potential considering its millions of urban households. This research work highlights techniques to combine geographic information systems (GIS) and object-based image recognition approach to identify the available rooftop area for PV deployment in a small scale region of DHA Phase 7 Karachi. A six step methodology has been adopted for the estimation of rooftop PV potential which involves geographic division of high resolution satellite imagery; sampling and rooftop feature extraction using FE tool of ENVI EX software; extrapolation of rooftop areas for the entire ROI using roof area-population relationship; visual inspection to analyze different rooftop factors such as building orientation, shading effect from trees and nearby buildings and other roof uses; a comparison of extracted rooftops to the physically measured sample rooftops, reduction for shading and other uses; and finally conversion to energy and power outputs. A relationship of total roof area and population of 13 m²/capita ±5% has been found. With higher efficiency rooftop PV panels, 12.24 MW of solar power can be generated which is 122.4% of peak power demand of DHA Phase 7.     

Estimation of Hong Kong’s solar energy potential using GIS and remote sensing technologies

This paper studies the use of Remote Sensing (RS) technologies and Geographic Information Systems (GIS) for estimation of city-wide photovoltaic (PV) potential in Hong Kong. It investigates the spatial distribution of cloud coverage through geostationary satellites from the Multi-functional Transport Satellite (MTSAT). The results indicate that a non-prominent spatial variation of cloud cover presides over a majority of Hong Kong territories. Appropriate locations for deploying solar PV panels, such as rooftops, were delineated using RS, GIS, and existing ancillary data. Extraction and filtering of pixels based on a set of criterions were used to identify optimal PV rooftops. This study shows that the summarization of PV potentials in Hong Kong is 2.66 TWh on building rooftops. The methodologies and findings from this study permits detailed spatial estimation of city-wide solar energy potential, and assists the policy-decision process on the use of renewable energy in Hong Kong.     

A hierarchical methodology for the mesoscale assessment of building integrated roof solar energy systems

Buildings and other engineered structures that form cities are responsible for a significant portion of the global and local impacts of climate change. Consequently, the installation of building integrated renewable energy sources such as photovoltaic or solar thermal systems on building rooftops is being widely investigated. Although the advantages for individual buildings have been studied, as yet there is little understanding of the potential benefits of urban scale implementation of such systems. Here we report the development of a new methodology for assessing the potential capacity and benefits of installing rooftop photovoltaic systems in an urbanized area. Object oriented image analysis and geographical information systems are combined with remote sensing image data to quantify the rooftop area available for solar energy applications and a renewable energy computer simulation is included to predict the potential benefits of urban scale photovoltaic system implementation. The new methodology predicts energy generation potential that can be utilized to meet Arizona’s Renewable Portfolio Standard 2025 renewable energy generation requirements.     

The European renewable energy target for 2030 – An impact assessment of the electricity sector

The European Union set binding targets for the reduction of greenhouse gases (GHG) and the share of renewable energy (RE) in final energy consumption by 2020. The European Council agreed to continue with this strategy through to 2030 by setting a RE target of 27% in addition to a GHG reduction target of 40%. We provide a detailed sectoral impact assessment by analyzing the implications for the electricity sector in terms of economic costs and the regional distribution of investments and shares of electricity generated from renewable energy sources (RES-E). According to the Impact Analysis by the European Commission the 27% RE target corresponds to a RES-E share of 49%. Our model-based sensitivity analysis on underlying technological and institutional assumptions shows that the cost-effective RES-E share varies between 43% and 56%. Secondly, we quantify the economic costs of these variants and those which would be incurred with higher shares. The long-term additional costs for higher RES-E shares would be less than 1% of total system costs. The third aspect relates to the regional distribution of EU-wide efforts for upscaling renewables. We point out that delivering high RES-E shares in a cost-effective manner involves considerably different efforts by the Member States.     

Photovoltaic electricity scenario analysis in urban contests: An Italian case study

This paper shows a methodology for the assessment of the photovoltaic potential in urban areas using Google Earth™ tool that provides either satellite images of the roofs of buildings or their number of floors by means of the Street View function. The applicability of the methodology has been tested on a selected urban area of the city of Palermo in the South of Italy. After classifying roofs according to the shape, orientation and pitch of buildings with different morphologies, the share of energy generated by the installable PV systems was evaluated with regard to the number of floors. Moreover the coverage of the electricity demand was investigated on the basis of the consumption of electricity of the households. The results of the energy assessment have been screened considering the economic feasibility of grid-connected photovoltaic systems. The proposed methodology permits to select a threshold number of floors of the buildings in correspondence of which the PV system that may be installed, and the consequent production of electricity, may not recover the costs for installation and maintenance of the system. This aspect has also been analyzed by considering the main factors that influence the computation, such as the mismatch between generated and consumed electricity and the shading effects due to the surrounding obstacles. The methodology could also be used to assess the effectiveness of the national incentives to support the diffusion of the PV systems in the short term.     

Five years left – How are the EU member states contributing to the 20% target for EU's renewable energy consumption; the role of woody biomass

The European Union has set ambitious targets of raising the share of EU energy consumption produced from renewable resources from 20% by 2020 to 27% by 2030. The aim of this paper is to assess the role of woody biomass in renewable energy as gross final energy consumption in the European Union (the EU-28). The paper identifies leading and lagging countries in biomass development by focusing on their current biomass use and forecasts future perspectives. The research compares and evaluates the role of biomass in renewable energy in the EU-28 focusing on countries' potential resources and policy support. The study shows that all countries are making efforts to reach the 20% target in 2020 and exhibit a trend of increasing renewable energy as gross final energy consumption towards the new target of 2030. Solid biomass plays an important role in reaching the EU's renewable energy targets. The majority of the EU-28 countries are close to reaching their national renewable energy targets and show a very attractive biomass development. Unless energy consumption decreases however, some member states will face serious problems in reaching their renewable energy target in 2020. Following our analysis, the largest problems occur in those MS having a relative high-energy consumption pattern: France, Germany and the United Kingdom. It is unlikely that they can comply with expected renewable energy demand, unless they mobilize more woody biomass from their available domestic potential (France, Germany) or considerably increase their woody biomass imports (mostly wood pellets) from elsewhere (United Kingdom).     

Solar photovoltaic (PV) energy; latest developments in the building integrated and hybrid PV systems

Environmental concerns are growing and interest in environmental issues is increasing and the idea of generating electricity with less pollution is becoming more and more attractive. Unlike conventional generation systems, fuel of the solar photovoltaic energy is available at no cost. And solar photovoltaic energy systems generate electricity pollution-free and can easily be installed on the roof of residential as well as on the wall of commercial buildings as grid-connected PV application. In addition to grid-connected rooftop PV systems, solar photovoltaic energy offers a solution for supplying electricity to remote located communities and facilities, those not accessible by electricity companies.The interest in solar photovoltaic energy is growing worldwide. Today, more than 3500 MW of photovoltaic systems have been installed all over the world. Since 1970, the PV price has continuously dropped [8]. This price drop has encouraged worldwide application of small-scale residential PV systems. These recent developments have led researchers concerned with the environment to undertake extensive research projects for harnessing renewable energy sources including solar energy. The usage of solar photovoltaic as a source of energy is considered more seriously making future of this technology looks promising.The objective of this contribution is to present the latest developments in the area of solar photovoltaic energy systems. A further objective of this contribution is to discuss the long-term prospect of the solar photovoltaic energy as a sustainable energy supply.     

全球太阳能热水器强制安装政策的先锋——巴塞罗那市

太阳能热水器是一种技术成熟、应用广泛的可再生能源产品和建筑节能产品。强制要求在建筑上安装太阳能热水器是近期各国政府较为推崇的一项激励政策,也得到了建筑行业和可再生能源行业的共同认可。目前实施太阳能热水器强制安装政策有以色列、西班牙、爱尔兰和意大利等国家和众多的欧洲城市,我国海南省、深圳市、济南市、邢台市等也开始实施强制安装政策。太阳能热水器强制安装政策的推动和实施经历了从城市到国家、从地方到中央的过程。西班牙巴塞罗那市是欧洲第一个实施太阳能热水器强制安装政策的城市,也是全球太阳能热水器强制安装政策的先锋,本文介绍了巴塞罗那市太阳能城市法令的制定和修订过程、强制安装政策的具体要求、政策实施过程中的经验和教训,希望对推动各地太阳能热水器强制安装政策的制定和实施有所帮助。     

European Workshop on Bioethanol Report of Meeting “Centre Borschette”, Brussels 19 February 1986

Since 1975, when the first energy R&;D programme was drawn up by the Council of Ministers, 5 successive multiannual programmes on renewable energies have been implemented by the European Commission in Brussels. The total budget spent on project support by the Commission during this period was 350 Mio ECU. The main emphasis has been on photovoltaics, biomass, wind energy and solar applications in buildings. The paper will summarize the main achievements of this European effort.     

Spanish energy roadmap to 2020: Socioeconomic implications of renewable targets

The European Union has established challenging targets for the share of renewable energies to be achieved by 2020; for Spain, 20% of the final energy consumption must be from renewable sources at such time. The aim of this paper is the analysis of the consequences for the electricity sector (in terms of excess cost of electricity, investment requirements, land occupation, CO₂ emissions and overcapacity of conventional power) of several possibilities to comply with the desired targets. Scenarios are created from different hypotheses for energy demand, biofuel share in final energy in transport, contribution of renewables for heating and cooling, renewable electricity generation (generation mix, deployment rate, learning curves, land availability) and conventional power generation (lifetime of current installations, committed deployment, fossil fuel costs and CO₂ emissions cost). A key input in the estimations presented is the technical potential and the cost of electricity from renewable sources, which have been estimated in previous, detailed studies by the present authors using a methodology based on a GIS (Geographical Information System) and high resolution meteorological data. Depending on the scenario, the attainment of the targets will lead to an increase in the cost of electricity from 19% to 37% with respect to 2007.     

A current and future state of art development of hybrid energy system using wind and PV-solar: A review

The wind and solar energy are omnipresent, freely available, and environmental friendly. The wind energy systems may not be technically viable at all sites because of low wind speeds and being more unpredictable than solar energy. The combined utilization of these renewable energy sources are therefore becoming increasingly attractive and are being widely used as alternative of oil-produced energy. Economic aspects of these renewable energy technologies are sufficiently promising to include them for rising power generation capability in developing countries. A renewable hybrid energy system consists of two or more energy sources, a power conditioning equipment, a controller and an optional energy storage system. These hybrid energy systems are becoming popular in remote area power generation applications due to advancements in renewable energy technologies and substantial rise in prices of petroleum products. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for, improving their performance, establishing techniques for accurately predicting their output and reliably integrating them with other conventional generating sources. The aim of this paper is to review the current state of the design, operation and control requirement of the stand-alone PV solar–wind hybrid energy systems with conventional backup source i.e. diesel or grid. This Paper also highlights the future developments, which have the potential to increase the economic attractiveness of such systems and their acceptance by the user.     

Techno-economic analysis for rustic electrification in Egypt using multi-source renewable energy based on PV/ wind/ FC

A technical-economic investigation based on mathematical modeling, simulation, and optimization approach is employed in this research to assemble an island combined renewable energy systems (CRES) consists of solar PV/Wind/Fuel Cell (FC) of a small-scale countryside area in Egypt. The intent of the proposed island CRES is to boost the share of renewable energy in the energy mix and to study the possibility of using fuel cells as a storage/backup system instead of using battery banks.Three combinations of CRES are presented in this research to select the most optimum one. The combinations of the hybrid systems are PV/FC, PV/WT/FC, and WT/FC. The performance and the total cost of the suggested CRES were optimized using Firefly Algorithm (FA). The results obtained from the FA are compared with those obtained from the Shuffled Frog Leaping Algorithm (SFLA) and the particle swarm optimization (PSO).The selected case study area with latitude and longitude of (29.0214 N, 30.8714 E) is identified for economic viability in this work.The simulation outcomes show that the solar PV/Wind/Fuel Cell combination incorporated with an electrolyzer for hydrogen production grants the excellent performance. The proposed system is economically viable with a levelized cost of energy of 0.47 $/kWh.     

Renewable energy in India: Status and potential

A majority of the Indian population does not have access to convenient energy services (LPG, electricity). Though India has made significant progress in renewable energy, the share of modern renewables in the energy mix is marginal. This paper reviews the status and potential of different renewables (except biomass) in India. This paper documents the trends in the growth of renewables in India and establishes diffusion model as a basis for setting targets. The diffusion model is fitted tot the past trends for wind, small hydro and solar water heating and is used to establish future targets. The economic viability and green house gas (GHG) saving potential is estimated for each option. Several renewables have high growth rates, for example wind, Photovoltaic (PV) module manufacture and solar water heaters. New technologies like Tidal, OTEC, Solar thermal power plants and geothermal power plants are at the demonstration stage and future dissemination will depend on the experience of these projects.     

Proposal for territorial distribution of the EU 2020 political renewable energy goal

This article first analyses the situation of indicators related to renewable energies in the reference year (2005) used by the European Union (EU) for its goal of a 20% share of energy from renewable sources in the gross final consumption of energy in 2020. Nonlinear distribution of dynamic targets is suggested for increasing the energy from renewable sources in gross final consumption of energy. This methodology is then applied to European Union member countries, the NUTS0 territorial aggregation level according to the EUROSTAT Nomenclature of Territorial Units for Statistics (NUTS), in the year 2020. Weighting was done based on share of energy from non-renewable sources in gross final consumption of energy, energy from non-renewable sources per capita, energy from non-renewable sources per GDP and GDP per capita in the EU-27 scenario. Finally, a multicriteria formula was applied to weight the variables used in this study.