Solar forecasting methods for renewable energy integration

The higher penetration of renewable resources in the energy portfolios of several communities accentuates the need for accurate forecasting of variable resources (solar, wind, tidal) at several different temporal scales in order to achieve power grid balance. Solar generation technologies have experienced strong energy market growth in the past few years, with corresponding increase in local grid penetration rates. As is the case with wind, the solar resource at the ground level is highly variable mostly due to cloud cover variability, atmospheric aerosol levels, and indirectly and to a lesser extent, participating gases in the atmosphere. The inherent variability of solar generation at higher grid penetration levels poses problems associated with the cost of reserves, dispatchable and ancillary generation, and grid reliability in general. As a result, high accuracy forecast systems are required for multiple time horizons that are associated with regulation, dispatching, scheduling and unit commitment. Here we review the theory behind these forecasting methodologies, and a number of successful applications of solar forecasting methods for both the solar resource and the power output of solar plants at the utility scale level.     

A new thinking for renewable energy model: Remote sensing‐based renewable energy model

This paper mainly focuses on the two issues through remote sensing: assessment of the renewable energy potential and integration of the renewable energy model. Three methods for assessing the renewable energy potential with remote sensing (RS) are proposed. The methods can provide more precise evaluation of renewable energy potential, which is the first vital step to develop renewable energy model. The paper then first presents three integrations of the renewable energy model with RS and points out that with respect to the problems one of them is employed. The assessment methods based on RS and the integrations with RS are illustrated by a simple example with Europe solar energy data set. The results show that Germany is the optimal country to install photovoltaic with a capacity of 137 125 GW. Copyright © 2009 John Wiley & Sons, Ltd.     

Solar radiation research for photovoltaic applications

This paper gives an overview of the fiscal year 1990 research activities and results under the Solar Radiation Research Task of the Photovoltaic Advanced Research and Development Project at the Solar Energy Research Institute. The activities under this task include developing and applying measurement techniques, instrumentation, and data analysis and modeling to understand and quantify the response of photovoltaic devices to variations in broad-band and spectral solar radiation.     

Solar radiation data for Quebec

Calculated values of solar radiation are presented for five Quebec sites in the form of tables giving for each month the average and extreme values of total radiation on a horizontal surface. These results are a summary of hourly values calculated from cloud observations for periods of 3–5 yr. Comparisons with measured values at Montreal show good agreement for hourly, daily and monthly radiation.     

Solar radiation data for indonesia

The solar radiation climate of Indonesia was surveyed from 1969 to 1976 as part of a project of the Meteorological and Geophysics Centre, Jakarta. Summaries of this survey have been presented in reports of the Centre for Meteorological and Geophysics primarily from the point of view of climatic studies. The study reported in the present paper has processed this data into computer compatible form and generated representative data years for use in the analysis of the performance of solar energy collecting systems. Comparison of irradiation conditions in Indonesia and neighbouring countries is also presented.     

The potential for renewable energy in industrial applications

To date, insufficient attention has been paid to the potential of renewable energy resources in industrial applications. Our analysis suggests that up to 21% of final energy demand and feedstock-use in the manufacturing industry sector could be of renewable origin by 2050, a five-fold increase over current levels in absolute terms. This estimate is considerably higher than other recent global scenario studies. In addition, if a 50% share of renewables in power generation is assumed, the share of direct and indirect renewable energy use rises to 31% in 2050. Our analysis further suggests that bioenergy and biofeedstocks can constitute three-quarters of the direct renewables use in this sector by 2050. The remainder is roughly evenly divided between solar heating and heat pumps. The potential for solar cooling is considered to be limited.While low-temperature solar process heat can reach cost-effectiveness today in locations with good insolation, some bioenergy applications will require a CO₂ price even on the longer term. Biomass feedstock for synthetic organic materials will require a CO₂ price up to USD 100/t CO₂, or even more if embodied carbon is not considered properly in CO₂ accounts. Future fossil fuel prices and bioenergy prices in addition to the development of feedstock commodity markets for biomass will be critical. Decision makers are recommended to pay more attention to the potential for renewables in industry. Finally, we propose the development of a detailed technology roadmap to explore this potential further and discuss key issues that need to be elaborated in such a framework.     

Solar energy storage for zootechnic applications

The main aim of this work is to make an economic evaluation of solar energy systems applied to the zootechnic field. As a typical application, a cattle-breeding farm was chosen, with the following energy requirements: stable heating during the cold season, heating of washing water, and the drying of hay during harvest. By means of a computer program simulating the hourly operative conditions of the whole system (solar source, storage and thermal load) it was possible to optimize the plant components in order to minimize energy costs. Results are referred to a plant situated in Sicily (Messina).     

Solar position algorithm for solar radiation applications

There have been many published articles describing solar position algorithms for solar radiation applications. The best uncertainty achieved in most of these articles is greater than ±0.01° in calculating the solar zenith and azimuth angles. For some, the algorithm is valid for a limited number of years varying from 15 years to a hundred years. This report is a step by step procedure for implementing an algorithm to calculate the solar zenith and azimuth angles in the period from the year −2000 to 6000, with uncertainties of ±0.0003°. The algorithm is described in a book written by Jean Meeus in 1998. This report is written in a step by step format to simplify the complicated steps described in the book, with a focus on the sun instead of the planets and stars in general. It also introduces some changes to accommodate for solar radiation applications. The changes include changing the direction of measuring azimuth angles to be measured from north and eastward instead of being measured from south and eastward, and the direction of measuring the observer’s geographical longitude to be measured as positive eastward from Greenwich meridian instead of negative. This report also includes the calculation of incidence angle for a surface that is tilted to any horizontal and vertical angle, as described by Iqbals in 1983.     

A survey of renewable energy technologies for rural applications

The availability of modern energy has long been recognized as one of the requirements for rural economic development. The recent advances that have been made in renewable energy technologies have broadened their applicability despite the recent decline in world oil prices. In this paper, we summarize the technology status of renewable energy technologies (photovoltaics, wind energy, hydro, and biomass technologies) that are considered appropriate for rural areas. In addition, we discuss the economic and institutional constraints that inhibit their widespread dissemination in rural areas.     

Solar radiation model

Solar radiation models for predicting the average daily and hourly global radiation, beam radiation and diffuse radiation are reviewed in this paper. Seven models using the Ångström–Prescott equation to predict the average daily global radiation with hours of sunshine are considered. The average daily global radiation for Hong Kong (22.3°N latitude, 114.3°E longitude) is predicted. Estimations of monthly average hourly global radiation are discussed. Two parametric models are reviewed and used to predict the hourly irradiance of Hong Kong. Comparisons among model predictions with measured data are made.     

Solar energy applications in India

The third meeting of the Solar Energy Working Group (India) was held at Indian Institute of Technology (IIT), Kanpur, on 14 and 15 January 1971. Scientists from Indian Institute of Technology, New Delhi; Motilal Nehru Engineering College, Allahabad; and Space Science and Technology Center, Trivandrum, participated for the first time, in addition to others already active in the field. Dr. K. N. Mathur was the chief guest and gave a special address. From reports and papers presented, it seems that more interest is being shown in work on air-conditioning and refrigeration at I.I.T Delhi and Madras, and Motilal Nehru Engineering College, Allahabad. Scientists at IIT Kanpur are concentrating on mass culture of algae, heat transfer studies, and agricultural drying. Defence Research Laboratory, Kanpur, is working on silicon solar cells. Scientists from Space Science and Technology Centre, Trivandrum, presented an interesting paper on ‘Solar simulation—state of the art’ as a part of space research program. The Deputy Director General of Observatories, New Delhi, actively participated in this meeting and gave assurance of having an improved network of solar radiation measurement stations in the country by the new stations which are starting to supply data. It is noteworthy that solar radiation distribution maps of India have now been prepared. The representatives of the Planning Commission (Government of India) outlined the present energy consumption in the country and stressed that in the coming years attempts should be made to use solar energy to partly replace kerosene (an imported commodity), which is a common source of energy in the rural areas of the country. This meeting clearly revealed the growing interest of Indian workers in solar energy and also their attempts to work in more varied fields, such as space applications and the mass culture of algae.     

Technological learning and renewable energy costs: implications for US renewable energy policy

This paper analyzes the relationship between current renewable energy technology costs and cumulative production, research, development and demonstration expenditures, and other institutional influences. Combining the theoretical framework of ‘learning by doing’ and developments in ‘learning by searching’ with the fields of organizational learning and institutional economics offers a complete methodological framework to examine the underlying capital cost trajectory when developing electricity cost estimates used in energy policy planning models. Sensitivities of the learning rates for global wind and solar photovoltaic technologies to changes in the model parameters are tested. The implications of the results indicate that institutional policy instruments play an important role for these technologies to achieve cost reductions and further market adoption.     

Identification of stakeholders for sustainable renewable energy applications in Cameroon

This paper examined the initiation, funding, realisation and the current state of some renewable energy applications in the West Region of Cameroon. The findings from the study conducted showed that all of the renewable energy applications were initiated by indigenes living outside the beneficiary communities. The lack of fee-for-service tariffs was partly responsible for the failure of a wind electric installation for potable water pumping. Conflicts in a local management committee resulted in the inoperative state of a pico-hydro installation, while the lack of finances accounted for the failure of a PV system of rural Health Centre. Although, some successful results were noted in the activities of African Center for Renewable and Sustainable Technologies (ACREST) involving foreign technical expertise in small scale renewable energy applications, ACREST had difficulties with the implementation of 100 kW micro hydro project. The stakeholders identified for successful renewable energy applications in Cameroon included local management committees, microfinance institutions, Non-Governmental Organisations (NGOs), Renewable Energy Enterprises (REEs) and universities. Local management committees must be in charge of the supervision, operation and maintenance of installed systems as well as revenue collection based on fee-for-service tariffs. Microfinance institutions should grant loans for the acquisition of financially and economically viable off-grid renewable energy systems to communities with monthly installments based on established monthly energy expenditures. NGOs are expected to provide technical assistance for the conception of community projects, the procurement of funding from cooperation partners and for the realisation of projects. REEs should have competence for sizing, installation and post-installation maintenance of renewable energy equipment. Universities must train the technicians and engineers that will be used by NGOs and REEs. This important role has been recognised by the government of Cameroon through the creation of the first Department of Renewable Energy at the University of Maroua in 2008.     

A renewable source based hydrogen energy system for residential applications

In this study, both concentrated solar power and wind energy systems are integrated with electrolyser, fuel cell and absorption cooling subsystems to supply power, cooling, heating and hydrogen to residential applications in an environmentally benign and efficient manner. These subsystems are integrated in a unique way to manage the excess power through water electrolysis to produce and store hydrogen. Integrated systems are thermodynamically analyzed, and their performance is assessed comparatively. Solar radiation intensity, inlet temperature and wind velocity are taken into account, and hence their effects on the system performance are investigated. The results of this study show that the present system appears to be efficient, environmentally friendly and hence sustainable.     

An optimization model for regional renewable energy development

This research effort details the modeling component of a comprehensive decision support system for energy planning that allows for combining existing electricity generating capabilities with increased use of renewable energy sources. It focuses on energy planning at the regional level, and it is illustrated by applying it to the greater southern Appalachian mountains of the eastern United States: a region that was chosen for analysis not only due to its heavy dependence on coal for electricity, but also because of its potential for increased use of wind and solar power. The paper specifically discusses the development of a multi-objective linear programming (MOLP) model that can be used to determine the optimal mix of renewable energy sources and existing fossil fuel facilities on a regional basis. This model allows a decision maker to balance annual generation costs against the corresponding greenhouse gas emissions, and it provides significant support for implementing a variety of different policy analyses.     

Hybrid renewable energy systems for power generation in stand-alone applications: A review

It has become imperative for the power and energy engineers to look out for the renewable energy sources such as sun, wind, geothermal, ocean and biomass as sustainable, cost-effective and environment friendly alternatives for conventional energy sources. However, the non-availability of these renewable energy resources all the time throughout the year has led to research in the area of hybrid renewable energy systems. In the past few years, a lot of research has taken place in the design, optimization, operation and control of the renewable hybrid energy systems. It is indeed evident that this area is still emerging and vast in scope. The main aim of this paper is to review the research on the unit sizing, optimization, energy management and modeling of the hybrid renewable energy system components. Developments in research on modeling of hybrid energy resources (PV systems), backup energy systems (Fuel Cell, Battery, Ultra-capacitor, Diesel Generator), power conditioning units (MPPT converters, Buck/Boost converters, Battery chargers) and techniques for energy flow management have been discussed in detail. In this paper, an attempt has been made to present a comprehensive review of the research in this area in the past one decade.     

Solar and wind energy applications in Hawaii

The study on solar radiation and wind power applications is a facet of the total State of Hawaii solar assessment program. Engineering consultants, governmental authorities from the Department of Energy, State of Hawaii, and counties, technology assessments specialists, and buinessmen were contacter for input into this paper. The resultant late 1977 survey is a broad implementation plan highlighting seven typical applications—three solar, three wind and one combination.It was not the intention of this study to produce refined engineering/economic analyses. However a principal objective was to stimulate the development of solar energy by assisting in the first crucial steps of the planning process.This investigation selected projects which had potential for immediate implementation in the State of Hawaii. Variety in form of application, type of engineering analysis and location within the State was sought. To a large extent these basic premises were well met, as applications range from agriculture to aquaculture to tourism to education on three islands.In varying degrees, each project is recommended either for further study or immediate implementation. Some of the economics may be dubious, as would be the situation in most original applications. However, with appropriate governmental aid or incentives, these pilot projects could serve to improve economy of scale, spur associated developments, and in the long run, improve Hawaii's balance of trade.     

Solar radiation data for Beer Sheva, Israel

A number of years of data on the global irradiation incident on a horizontal surface in Beer Sheva, Israel (lat. = 31°15′N, long. = 34°48′E, elevation 240 m) have been correlated. It is apparent from these data that this locale possesses a relatively high abundance of sunshine. The average cumulative annual irradiation is 6722MJ/m² and the average daily irradiation is 18.43 MJ/m². The percentage frequency of days possessing irradiation rates greater than 20 MJ/m² is 46 per cent, whereas that possessing less than 10 MJ/m²d is 11.9 per cent. The percentage frequency of cloudy days (K_T < 0.34) is low, 7.5 per cent, whereas that for clear days (K_T > 0.65) is 29.2 per cent.     

Artificial neural networks in renewable energy systems applications: a review

Artificial neural networks are widely accepted as a technology offering an alternative way to tackle complex and ill-defined problems. They can learn from examples, are fault tolerant in the sense that they are able to handle noisy and incomplete data, are able to deal with non-linear problems and, once trained, can perform prediction and generalisation at high speed. They have been used in diverse applications in control, robotics, pattern recognition, forecasting, medicine, power systems, manufacturing, optimisation, signal processing and social/psychological sciences. They are particularly useful in system modelling such as in implementing complex mappings and system identification. This paper presents various applications of neural networks mainly in renewable energy problems in a thematic rather than a chronological or any other order. Artificial neural networks have been used by the author in the field of solar energy; for modelling and design of a solar steam generating plant, for the estimation of a parabolic trough collector intercept factor and local concentration ratio and for the modelling and performance prediction of solar water heating systems. They have also been used for the estimation of heating loads of buildings, for the prediction of air flow in a naturally ventilated test room and for the prediction of the energy consumption of a passive solar building. In all those models a multiple hidden layer architecture has been used. Errors reported in these models are well within acceptable limits, which clearly suggest that artificial neural networks can be used for modelling in other fields of renewable energy production and use. The work of other researchers in the field of renewable energy and other energy systems is also reported. This includes the use of artificial neural networks in solar radiation and wind speed prediction, photovoltaic systems, building services systems and load forecasting and prediction.