Solar energy scenarios in Brazil. Part two: Photovoltaics applications

This paper discusses some energy scenarios for photovoltaic applications in Brazil engendered by using SWERA database in order to demonstrate its potential for feasibility analysis and application in the energy planning for electricity generation. It discusses two major different markets: hybrid PV–Diesel installations in mini-grids of the off-grid Brazilian electricity system in the Amazon region, and grid-connected PV in urban areas of the interconnected Brazilian electricity system. The potential for using PV is huge, and can be estimated in tens to hundreds of MWp in the Amazon region alone, even if only a fraction of the existing Diesel-fired plants with a total installed capacity of over 620 MVA would fit to run in an optimum Diesel/PV mix. Most of the major cities in Brazil present greater electricity demand in summertime with the demand peak happening in the daytime period. This energy profile match the actual solar resource assessment provided by SWERA Data Archive, enabling grid-connected PV systems to provide an important contribution to the utility's capacity.     

An application of the multilayer perceptron: Solar radiation maps in Spain

In this work an application of a methodology to obtain solar radiation maps is presented. This methodology is based on a neural network system [Lippmann, R.P., 1987. An introduction to computing with neural nets. IEEE ASSP Magazine, 4–22] called Multi-Layer Perceptron (MLP) [Haykin, S., 1994. Neural Networks. A Comprehensive Foundation. Macmillan Publishing Company; Hornik, K., Stinchcombe, M., White, H., 1989. Multilayer feedforward networks are universal approximators. Neural Networks, 2(5), 359–366]. To obtain a solar radiation map it is necessary to know the solar radiation of many points spread wide across the zone of the map where it is going to be drawn. For most of the locations all over the world the records of these data (solar radiation in whatever scale, daily or hourly values) are non-existent. Only very few locations have the privilege of having good meteorological stations where records of solar radiation have being registered. But even in those locations with historical records of solar data, the quality of these solar series is not as good as it should be for most purposes. In addition, to draw solar radiation maps the number of points on the maps (real sites) that it is necessary to work with makes this problem difficult to solve. Nevertheless, with the application of the methodology proposed in this paper, this problem has been solved and solar radiation maps have been obtained for a small region of Spain: Jaén province, a southern province of Spain between parallels 38°25′ N and 37°25′ N, and meridians 4°10′ W and 2°10′ W, and for a larger region: Andalucía, the most southern region of Spain situated between parallels 38°40′ N and 36°00′ N, and meridians 7°30′ W and 1°40′ W.     

Electric energy generation from small-scale solar and wind power in Brazil: The influence of location,area and shape

Power production from renewable sources is identified as one of the tools to attain sustainable development in economic and social terms in Brazil. Awareness of how to prioritize renewable energy sources and technologies becomes increasingly important. Solar and wind energy have been highlighted in this context as being clean, safe and also relatively mature technologies. In addition, they are also renowned for having great energy potential and allowing different mounting options for energy harvesting systems. This article seeks to contribute to the knowledge of the effects that the key attributes, location, area and shape, of a site can have on the potential of renewable generation. In order to incorporate these attributes into an integrated analysis, a comparison method is developed and subsequently applied in a case study for two Brazilian cities. Results indicate that the amount of energy obtained by a given power generation system can undergo large variations depending on the characteristics of attributes such as site location, area and shape. This variation may ultra-pass 200%, in some cases, which demonstrates the importance of a better understanding of the role of these attributes in determining energy production.     

Solar energy resource assessment — Brazil

Appropriate information on solar resources is very important for a variety of technological areas, such as: agriculture, meteorology, forestry engineering, water resources and particularly for an innovating technology such as solar energy. In the market entry process of an innovating technology such as solar energy, the enlarged and sustained reproduction of this energy strongly depends on the economy and reliability of the demonstrative solar systems installed (within a restricted or wide scale). The economy and reliability of a system are the consequence of a well-prepared project, resulting from an accurate knowledge of the solar resource available. Therefore, knowing the potential of the solar resource accurately is not only a need, it is also an imperative for a larger diffusion and use of the solar energy.The existing sources of information on radiation in Brazil are quite varied, both at the institutional level and in different types of publications. At the institutional level these sources are: the National Institute of Meteorology, secretary of agriculture, research centers, universities, and electric power generating and distributing companies, among others. The publications with this information are project reports, internal reports of institutions or several magazines. Thus, the quality of the data varies considerably, the information presents spatial and temporal discontinuity and the instruments as well as the measurement units are not standardized.The general objective of this paper is to recover, qualify, standardize and make available the best information from the current existing solar resource in Brazil, either in the form of isoline charts of solar radiation, insolation, numeric tables or analytic summaries of a great part of the publications on the theme over the last forty years.     

Solar energy outlook in Malaysia

Predicted to be the clean energy of tomorrow, solar energy has been in the forefront of energy development in many developed countries and a potential source of energy to developing countries like Malaysia. This paper presents Malaysia's solar energy or solar photovoltaic developmental outlook. The study is done by first looking into the country's energy policies related to solar energy. Key players in the solar energy development such as government institutions are introduced. Early solar energy programmes and a key project called Malaysia Building Integrated Photovoltaic (MBIPV) as well as its successful initiatives will be presented. Measures which have taken by the government of Malaysia including attractive incentives to encourage solar photovoltaic development, the country's potential in solar energy, foreign investments and future directions as well a feed-in tariff scheme will be presented in length to provide a broad spectrum of solar energy development in Malaysia. The outlook has been positive and the country is active in promoting solar as an alternative energy and is aware of benefits it will bring toward its economic development in the future.     

Solar energy in Malaysia: Current state and prospects

Malaysia is situated at the equatorial region with an average solar radiation of 400-600 MJ/m² per month. It has a promising potential to establish large scale solar power installations; however, solar energy is still at the infancy stage due to the high cost of photovoltaic (PV) cells and solar electricity tariff rate. The Malaysian government is keen to develop solar energy as one of the significant sources of energy in the country. According to the 9th Malaysia Plan (9MP), a large allocation had been dedicated for implementation of solar PV systems. On 25th July 2005, a Malaysian Building Integrated Photovoltaic (MBIPV) project had been announced and it was planned to end by 2010. The project consists of three categories which include: BIPV demonstration, national “SURIA1000” and BIPV showcase. Greater emphasis will be placed on energy efficiency under the Tenth Malaysia Plan (2011-2015). This paper discusses present and future situation of solar power in Malaysia, utilization of solar energy and the strategies taken by the Malaysian government and Non-Government Organizations (NGOs) to promote solar energy thermal applications and electricity power generation in the future.     

Solar energy in India: Strategies, policies, perspectives and future potential

Renewable energy sources and technologies have potential to provide solutions to the longstanding energy problems being faced by the developing countries like India. Solar energy can be an important part of India's plan not only to add new capacity but also to increase energy security, address environmental concerns, and lead the massive market for renewable energy. Solar thermal electricity (STE) also known as concentrating solar power (CSP) are emerging renewable energy technologies and can be developed as future potential option for electricity generation in India. In this paper, efforts have been made to summarize the availability, current status, strategies, perspectives, promotion policies, major achievements and future potential of solar energy options in India.     

Solar energy: Markets, economics and policies

Solar energy has experienced phenomenal growth in recent years due to both technological improvements resulting in cost reductions and government policies supportive of renewable energy development and utilization. This study analyzes the technical, economic and policy aspects of solar energy development and deployment. While the cost of solar energy has declined rapidly in the recent past, it still remains much higher than the cost of conventional energy technologies. Like other renewable energy technologies, solar energy benefits from fiscal and regulatory incentives, including tax credits and exemptions, feed-in-tariff, preferential interest rates, renewable portfolio standards and voluntary green power programs in many countries. The emerging carbon credit markets are expected to provide additional incentives to solar energy deployment; however, the scale of incentives provided by the existing carbon market instruments, such as, the Clean Development Mechanism of the Kyoto Protocol is limited. Despite the huge technical potential, the development and large scale deployment of solar energy technologies world-wide still has to overcome a number of technical, financial, regulatory and institutional barriers. The continuation of policy supports might be necessary for several decades to maintain and enhance the growth of solar energy in both developed and developing countries.     

Climate policy scenarios in Brazil: A multi-model comparison for energy

This paper assesses the effects of market-based mechanisms and carbon emission restrictions on the Brazilian energy system by comparing the results of six different energy-economic or integrated assessment models under different scenarios for carbon taxes and abatement targets up to 2050. Results show an increase over time in emissions in the baseline scenarios due, largely, to higher penetration of natural gas and coal. Climate policy scenarios, however, indicate that such a pathway can be avoided. While taxes up to 32 US$/tCO₂e do not significantly reduce emissions, higher taxes (from 50 US$/tCO₂e in 2020 to 16 2US$/tCO₂e in 2050) induce average emission reductions around 60% when compared to the baseline. Emission constraint scenarios yield even lower reductions in most models. Emission reductions are mostly due to lower energy consumption, increased penetration of renewable energy (especially biomass and wind) and of carbon capture and storage technologies for fossil and/or biomass fuels. This paper also provides a discussion of specific issues related to mitigation alternatives in Brazil. The range of mitigation options resulting from the model runs generally falls within the limits found for specific energy sources in the country, although infrastructure investments and technology improvements are needed for the projected mitigation scenarios to achieve actual feasibility.     

Solar energy storage using surfactant micelles

The photogalvanic behaviour of iron-thionine and iron-methylene blue systems in the presence of surfactants has been studied. The data indicate that the surfactant micelles can be utilized for the storage of light energy.     

Solar energy conversion through phase transformations

Sodium thiosulphate pentahydrate and sodium sulphate decahydrate show appreciable potential differences and currents when the solid phase is in contact with its molten phase. the studies offer a new method for converting solar energy into electrical power.     

Solar energy investments in a developing economy

Almost all technical development efforts in both the developed and the developing nations depend on electrical energy. However, the sources of conventional means of electricity generation are fast depleting. Consequently, most industrialised nations have research on solar energy as a way to avert impending energy crisis.This paper presents the investments in energy generation in Nigeria. The efforts made in solar energy research and utilization are highlighted. The financial investments by the Nigerian government to the development of electrical power industry between 1990 and 1994 are presented and discussed. A case is made for a systematic and coordinated financial investments in solar energy research and adaptation to complement power generation from conventional sources.     

Socio-geographic perception in the diffusion of innovation: Solar energy technology in Sri Lanka

Understandings of the diffusion process have tended to emphasize either the adoption perspective, which focuses on individual characteristics, or the market perspective, which focuses on institutional context. In this paper we bring these two perspectives together by recognizing that people are embedded in socio-geographic contexts that affect their perceptions of their situations, which in turn shape the innovativeness of individuals and places. Focusing on the diffusion of Solar Home Systems (SHS) in Sri Lanka, we explore the role of context at the village (by comparing adoption rates among villages) and individual (by comparing time-to-adoption among household decision makers in a case-study village) scales. At the village scale, we find that expectations of government policy based on interactions related to ethnicity and politicians’ previous power-grid connection promises are significant drivers of SHS adoption, along with perceived tolerance levels in the village for non-conformist behavior. Among household decision makers within the case-study village, we analyze relative adoption time and the duration of the innovation-decision process and find that perceiving strong village-level social control inhibits SHS adoption decision making. The results add to innovation diffusion theory and provide policy recommendations for agencies promoting solar energy in developing countries.     

Solar hydrogen production: A comparative performance assessment

Hydrogen is a sustainable fuel option and one of the potential solutions for current energy and environmental problems. Its eco-friendly production is really crucial for better environment and sustainable development. In this paper, various solar hydrogen production methods are discussed. A comparative performance assessment study of solar thermal and photovoltaic (PV) hydrogen production methods is carried out. It is found that the solar thermal hydrogen production via electricity production is an environmentally benign method and possesses higher exergy efficiency than PV hydrogen production. However, the latter is better in a way that it does not involve any moving parts. PV hydrogen production suffers lower exergy efficiency because of low PV efficiency.     

On improvement rates for renewable energy technologies: Solar PV,wind turbines,capacitors, and batteries

An important issue in various domains of renewable energy is the use of technological improvement trends to project future capabilities of energy technologies. This paper analyzes two pairs of renewable energy technologies and finds that the annual improvement rate of cost/investment is quite different for the four technological domains: namely, solar photovoltaics (PV) (9.0% per year), wind turbines (2.9%), batteries (3.1%) and capacitors (21.1%). While these trends have been reasonably consistent over long time frames, projecting these trends into the future without a better understanding of the underlying causes of the improvements is not at all reliable. This paper establishes theoretical fundamentals for explaining the differences in such rates and a framework for empirically probing such explanations using patent data. Employing this framework, this study collects and analyzes a set of highly representative patents for each of the four domains, allowing measurement of: patenting rates, reliance on scientific literature and other characteristics of the different fields. Our study of the inventions, while not establishing an indisputable causal relationship for the differing rates, establishes a broader theoretical basis for why such rates differ so greatly and why they might be stable over time. Among many possible effects, this study indicates that the age of knowledge utilized in the patents and the percentage of very important inventions in the field are the most likely significant contributors to higher rates of advance.     

Solar space heating and cooling for Spanish housing: Potential energy savings and emissions reduction

An experimental solar energy facility was designed to meet as much of the heating demand in a typical Spanish dwelling as possible. With a view to using the facility during the summer and preventing overheating-induced deterioration of the solar collectors in that season of the year, an absorption chiller was fitted to the system to produce solar-powered air conditioning. The facility operated in solar space heating mode in the winter of 2008–2009 and in cooling mode during the summer of 2008. The design was based on a new type of flat plate vacuum solar collectors that delivered higher efficiency than conventional panels. This type of collectors can reach temperatures of up to 110 °C in the summer and up to 70 °C on the coldest winter days. The solar facility comprised a 48-m² (with a net area of 42 m²) solar collector field, a 25-kW plate heat exchanger, a 1500-l storage tank, a 4.5-kW (Rotartica) air-cooled absorption chiller and several fan coils. The facility was tested by using it to heat and cool an 80-m² laboratory located in Madrid. As the average area of Spanish homes is 80 m², the findings were generally applicable to national housing. The solar facility was observed to be able to meet 65.3% of the space heating demand. For air conditioning, the system covered 46% of the demand, but with high indoor temperatures. In other words, the collector field was found to be able to air condition only half of the home (40 m²). Lastly, the savings in CO₂ emissions afforded by the use of this facility compared to conventional air conditioning were calculated, along with its amortisation period. These results have been extrapolated calculating the potential energy savings and emissions reduction for all the Spanish households.     

Solar energy development in China—A review

The steady and maintainable electric power provides the development momentum of a country's industrialization, which is indispensable to every country at present. It is well known that China is the largest developing country in the world. With the rapid development of economy and society, energy demand of Chinese society is increasing in an incredible speed, i.e., the annual accumulative total capacity of electric energy is about 0.1 billion kW, and the most of them is provided by the fossil fuel resource, and the share is about 90% in China. Certainly, it is a very inappropriate energy structure, so the sustainable development of country is impossible in future, the status must be improved in order to achieve sustainable development. Fortunately, China has large country area, and there are abundant solar resources. Development and application of solar energy have been regarded by the government and ordinary people, and they thought that solar energy can provide more and more electric energy in future, and more and more actual examples have been applied in the last decades, which are supported by central government and local governments. This paper discusses the distribution zone and current developmental situation of solar energy in China. Then, some application practice is described, such as solar energy greenhouse, solar energy hearth, solar water heater, solar lighting system, solar water pump, distributed generation (DG), grid-connect photovoltaic generation (GPG) and wind–solar hybrid system. The policies and law of China central government and local governments are described in the following paragraph. At the end, the developmental prospect of photovoltaic (PV) in future China and the development barriers and recommendations are introduced.     

Solar gas turbine systems: Design, cost and perspectives

The combination of high solar shares with high conversion efficiencies is one of the major advantages of solar gas turbine systems compared to other solar-fossil hybrid power plants. Pressurized air receivers are used in solar tower plants to heat the compressed air in the gas turbine to temperatures up to 1000 °C. Therefore solar shares in the design case of 40% up to 90% can be realized and annual solar shares up to 30% can be achieved in base load. Using modern gas turbine systems in recuperation or combined cycle mode leads to conversion efficiencies of the solar heat from around 40% up to more than 50%. This is an important step towards cost reduction of solar thermal power. Together with the advantages of hybrid power plants—variable solar share, fully dispatchable power, 24 h operation without storage—solar gas turbine systems are expected to have a high potential for market introduction in the mid term view.In this paper the design and performance assessment of several prototype plants in the power levels of 1 MW, 5 MW and 15 MW are presented. Advanced software tools are used for design optimization and performance prediction of the solar tower gas turbine power plants. Detailed cost assumptions for the solarized gas turbine, the solar tower plant and further equipment as well as for operation and maintenance are presented. Intensive performance and economic analysis of the prototype plants for different locations and capacity factors are shown. The cost reduction potential through automation and remote operation is revealed.     

Solar energy utilization for heating of indoor swimming pool

A simple transient analytical approach has been adopted for developing an explicit expression for the water temperature of an indoor swimmingpool coupled to a panel of collectors. For qualitative assessment of the analytical results, computations have been made for the winter climatic conditions of Sri Nagar, India. The effects of several parameters, viz. inlet temperature, heat removal factors, collector, etc. on the performance of the proposed systems have been studied in detail. It is observed that (i) the proposed model agrees with the experimental results of the Australian passive solar swimming pool and (ii) the desired temperature for the indoor swimming pool can be achieved by the active method.     

Solar energy conversion with hot electrons from impact ionisation

Impact ionisation in combination with carrier-carrier scattering in the absence of phonon scattering in an illuminated semiconductor leads to an energy distribution of electrons in the conduction band and of holes in the valence band which is best described by a single Fermi-distribution with no splitting of quasi-Fermi-energies, but with a temperature different from the lattice temperature. To make proper use of this distribution in a solar cell, electrons and holes must be withdrawn through membranes, which are composed of narrow band, large bandgap semiconductors and which allow only electrons or holes in a narrow energy range to be transmitted. Current-voltage characteristics and efficiencies are calculated analytically for maximum concentration of the solar radiation. A maximal efficiency of 85% is found for a vanishing bandgap of the solar cell material.