Complimentary nature of wind and solar energy at a continental mid-latitude station

Daily values of solar and wind energy have been used (i) to study renewable energy availability at various times of year, (ii) to test the level of persistence for inferences about the practicality of energy storage and (iii) to examine the complementary behaviour of these two daily time series on both seasonal and daily bases. Results for the station studied (central Iowa) show a bimodal distribution for winter solar energy, whereas non-winter solar and wind (all seasons) show unimodal distributions. Wind and solar energy were observed to be highly complementary on an annual basis, but only slightly complementary on a daily basis.     

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.     

An application of a combined wind and solar energy system in Izmir

In this work, a combined system which is produced electrical energy from both solar radiation via solar cells and wind energy by using wind turbine was studied. For wind energy, measurements of wind velocities at 12 m height were taken. Then, these values were calculated for 42 m by using Hellmann equation. After that, wind energy converted to the electrical energy. However, value of solar radiation from solar cells was taken at the optimum slope angle of collector which provided higher energy production for each 1 h during this application. Thus, obtained data from each system were used together for finding total energy. For this study, measurements, which would be used in calculation of wind energy and solar energy were taken for four years between 1995 and 1998 in Izmir. As a result, energy of the combined system could support each other when one of them produces energy insufficiently.     

Combining wave energy with wind and solar: Short-term forecasting

While wind and solar have been the leading sources of renewable energy up to now, waves are increasingly being recognized as a viable source of power for coastal regions. This study analyzes integrating wave energy into the grid, in conjunction with wind and solar. The Pacific Northwest in the United States has a favorable mix of all three sources. Load and wind power series are obtained from government databases. Solar power is calculated from 12 sites over five states. Wave energy is calculated using buoy data, simulations of the ECMWF model, and power matrices for three types of wave energy converters. At the short horizons required for planning, the properties of the load and renewable energy are dissimilar. The load exhibits cycles at 24 h and seven days, seasonality and long-term trending. Solar power is dominated by the diurnal cycle and by seasonality, but also exhibits nonlinear variability due to cloud cover, atmospheric turbidity and precipitation. Wind power is dominated by large ramp events–irregular transitions between states of high and low power. Wave energy exhibits seasonal cycles and is generally smoother, although there are still some large transitions, particularly during winter months. Forecasting experiments are run over horizons of 1–4 h for the load and all three types of renewable energy. Waves are found to be more predictable than wind and solar. The forecast error at 1 h for the simulated wave farms is in the range of 5–7 percent, while the forecast errors for solar and wind are 17 and 22 percent. Geographic dispersal increases forecast accuracy. At the 1 h horizon, the forecast error for large-scale wave farms is 39–49 percent lower than at individual buoys. Grid integration costs are quantified by calculating balancing reserves. Waves show the lowest reserve costs, less than half wind and solar.     

Policy analysis of authorisation procedures for wind energy deployment in Spain

The aim of this paper is to analyse the administrative procedures for the granting of authorisations for the siting of wind farms in Spain, currently the competency of regional authorities. The analysis reveals some commonalities and differences between the procedures across regions. Furthermore, some aspects regarding these procedures have raised the concern of different stakeholders, including the central government and wind energy investors. A conflict between the interests of the central and regional governments can be observed. Lack of coordination between the different administrative levels and the “more is better mentality” of regional authorities have led to a significant growth of wind energy requests for the (national) feed-in tariff. In turn, investors have complained about the discretionarity and non-transparency of those procedures and the lack of homogeneity across regions. This is likely to result in delays, uncertainty for investors and higher transaction costs. Although there has been a trend to a model which involves the use of multicriteria bidding procedures with more explicit, objective and precise criteria regarding project selection, the aforementioned problems suggest the need to improve coordination between the different administrative levels.     

Utilizing wind and solar energy as power sources for a hybrid building ventilation device

Wind and solar energy are currently used to power many building ventilation devices. Such devices rely exclusively on either solar or wind energy, which limits their usefulness. A low-cost hybrid ventilation device that utilizes both wind and solar energy as power sources was designed to overcome some of the shortcomings of these devices. Wind tunnel testing conducted at the aerodynamics laboratory of the University of New South Wales revealed that the hybrid device had improved operational and performance benefits compared with conventional commercial roof top ventilators, particularly at zero to low wind speeds. This represents a significant step forward and will have an immediate impact in promoting the use of clean energy for the purposes of building ventilation.     

A solar and wind driven energy system for hydrogen and urea production with CO2 capturing

A novel solar PV and wind energy based system is proposed in this study for capturing carbon dioxide as well as producing hydrogen, urea and power. Both Aspen Plus and EES software packages are employed for analyses and simulations. The present system is designed in a way that PEM electrolyzer is powered by the wind turbines for hydrogen production, which is further converted into ammonia and then synthesizes urea by capturing CO₂ and additional power is supplied to the community. The solar PV is employed to power the cryogenic air separation unit and the additional power is used for the industrial purpose. In the proposed system, ammonia does not only capture CO₂ but also synthesizes urea for fertilizer industry. The amount of electrical power produced by the system is 2.14 MW. The designed system produces 518.4 kmol/d of hydrogen and synthesizes 86.4 kmol/d of urea. Furthermore, several parametric studies are employed to investigate the system performance.     

Small wind turbine energy policies for residential and small business usage in Ontario,Canada

This paper examines the social barriers, policies, and incentive programs for residential and small business small wind (RBSW) projects, particularly in Ontario, Canada, as well as comparisons with California, US, and the United Kingdom. The alignment between socio-political and community acceptance is considered for its impact on market acceptance of the technology. Barriers inhibiting social acceptance of RBSW projects include adequate capacity factor, cost effectiveness, wind variability, audio-esthetics impact, health and safety, procedural fairness, and transparency. A review of the policies for implementation of small wind projects in each location is presented. Strategies to overcome barriers to social acceptance are examined, along with recommendations for the increased implementation of RBSW projects worldwide. Recommendations to increase social acceptance and subsequent implementation of RBSW projects include the collaboration of government agencies, industry and community members, during RBSW implementation processes, and the provision of consistent, long-term, supportive policies and incentive programs for project owners.     

Assessing the lifecycle greenhouse gas emissions from solar PV and wind energy: A critical meta-survey

This paper critically screens 153 lifecycle studies covering a broad range of wind and solar photovoltaic (PV) electricity generation technologies to identify 41 of the most relevant, recent, rigorous, original, and complete assessments so that the dynamics of their greenhouse gas (GHG) emissions profiles can be determined. When viewed in a holistic manner, including initial materials extraction, manufacturing, use and disposal/decommissioning, these 41 studies show that both wind and solar systems are directly tied to and responsible for GHG emissions. They are thus not actually emissions free technologies. Moreover, by spotlighting the lifecycle stages and physical characteristics of these technologies that are most responsible for emissions, improvements can be made to lower their carbon footprint. As such, through in-depth examination of the results of these studies and the variations therein, this article uncovers best practices in wind and solar design and deployment that can better inform climate change mitigation efforts in the electricity sector.     

Solar and wind energy potential and utilization in Pakistan

Pakistan needs substantial amount of energy to develop its industry and to increase the agricultural productivity. The available indigenous energy resources are limited. The only option which the country has to pursue is renewable energy. This paper identifies the potentials of solar and wind energy. The prime sites for wind are coastal area, arid zone and hill terrains. Solar energy is abundant over most part of the country, maximum being received over Quetta valley.     

Double-sided wet fabric evaporator utilizing wind and solar energy efficiently — One-dimensional transient simulations

The performance of the double-sided fabric seawater evaporator suggested by Nosoko et al. (Desalination and Water Treatment16 (2010) 254) was simulated for a sunny day under subtropical and maritime climate conditions by a one-dimensional transient modeling. The concentration of seawater increases exponentially with the downstream distance along the fabric while the temperature and the evaporation rate increase gradually. In a polyester fabric, seawater flows fast and the concentration of the effluent brine is kept constant in a small range by adjusting the rate of influent seawater according with the solar radiation. In a cotton fabric, seawater flows slow, causes a large time lag between the influent and effluent, and thus varies the effluent concentration greatly. The temperature and evaporation rate of the polyester are approximately the same as those of the cotton. The daily evaporation is 9.41 kg/day ⋅ m² − fabric under a solar radiation of 27.6MJ/m². Lumped capacitance model (Desalination and Water Treatment16 (2010) 254) was found to predict quite accurately the averages of the evaporation rate and temperature of fabric, but to fail in prediction of the temporal variations of the effluent concentration.     

Effect of wind energy system performance on optimal renewable energy model-an analysis

The Optimal Renewable Energy Model (OREM) has been developed to determine the optimum level of renewable energy sources utilisation in India for the year 2020–21. The model aims at minimising costefficiency ratio and determines the optimum allocation of different renewable energy sources for various end-uses. The extent of social acceptance level, potential limit, demand and reliability will decide the renewable energy distribution pattern and are hence used as constraints in the model. In this paper, the performance and reliability of wind energy system and its effects on OREM model has been analysed. The demonstration windfarm (4 MW) which is situated in Muppandal, a village in the southern part of India, has been selected for the study. The windfarm has 20 wind turbine machines of 200 KW capacity. The average technical availability, real availability and capacity factor have been analysed from 1991 to 1995 and they are found to be 94.1%, 76.4% and 25.5% respectively. The reliability factor of wind energy system is found to be 0.5 at 10,000 hours. The OREM model is analysed considering the above said factors for wind energy system, solar energy system and biomass energy systems. The model selects wind energy for pumping end-use to an extent of 0.3153×10¹⁵ KJ.     

A demonstrative study for the wind and solar hybrid power system

In March 1995, a small scale wind and solar hybrid power system was installed at Ashikaga Institute of Technology. Until now, the authors have acquired the data of the output of the hybrid power plant along with wind speed, wind direction, and the solar radiation, in order to demonstrate a complementary relationship between solar energy and wind energy.After nine months operation of the system, the authors confirmed that there exists a complementary relationship between solar energy and wind energy. We also found, however, that the power output by wind does not have much prospect compared to that by solar cell especially in summer season in Ashikaga area.     

Wind energy and assessment of wind energy potential in Turkey

In this study, the potential of wind energy and assessment of wind energy systems in Turkey were studied. The main purpose of this study is to investigate the wind energy potential and future wind conversion systems project in Turkey. The wind energy potential of various regions was investigated; and the exploitation of the wind energy in Turkey was discussed. Various regions were analyzed taking into account the wind data measured as hourly time series in the windy locations. The wind data used in this study were taken from Electrical Power Resources Survey and Development Administration (EIEI) for the year 2010. This paper reviews the assessment of wind energy in Turkey as of the end of May 2010 including wind energy applications. Turkey's total theoretically available potential for wind power is around 131,756.40 MW and sea wind power 17,393.20 MW annually, according to TUREB (TWEA). When Turkey has 1.5 MW nominal installed wind energy capacity in 1998, then this capacity has increased to 1522.20 MW in 2010. Wind power plant with a total capacity of 1522.20 MW will be commissioned 2166.65 MW in December 2011.     

Experimental and simulation study on wind affecting particle flow in a solar receiver

The solid particle receiver (SPR) is a direct absorption central receiver that can provide a solar interface with thermal storage for thermo-chemical hydrogen production processes requiring heat input at temperatures up to 1000 °C. In operation, a curtain made up of approximately 697 μm ceramic particles is dropped within the receiver cavity and directly illuminated by concentrated solar energy. Since the SPR has an open aperture, the flow may be disturbed by high ambient winds. Therefore, the objective of this study was to gain insight into the wind effect on the curtain. Experiments were conducted to understand the wind influence on the particle flow and loss. The experimental results showed that winds from certain angles of the attack could cause a critical loss of particles. A MFIX simulation model was developed to validate the experimental results and observation. The simulation has provided us with better understanding on the wind effects.     

Development and assessment of a solar,wind and hydrogen hybrid trigeneration system

A solar-wind hybrid trigeneration system is proposed and analyzed thermodynamically through energy and exergy approaches in this paper. Hydrogen, electricity and heat are the useful products generated by the hybrid system. The system consists of a solar heliostat field, a wind turbine and a thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production linked with a hydrogen compression system. A solar heliostat field is employed as a source of thermal energy while the wind turbine is used to generate electricity. Electric power harvested by the wind turbine is supplied to the electrolyzer and compressors and provides an additional excess of electricity. Hydrogen produced by the thermochemical copper-chlorine (Cu-Cl) cycle is compressed in a hydrogen compression system for storage purposes. Both Aspen Plus 9.0 and EES are employed as software tools for the system modeling and simulation. The system is designed to achieve high hydrogen production rate of 455.1 kg/h. The overall energy and exergy efficiencies of the hybrid system are 49% and 48.2%, respectively. Some additional results about the system performance are obtained, presented and discussed in the paper.     

Locating solar and wind parks in South-Eastern Nigeria for maximum population coverage: A multi-step approach

Power outages in the most populous country in the continent of Africa, Nigeria, is one issue that has woefully defied almost all known hypotheses for centuries, as enormous investments over the years have provided no palpable result. Considering that electricity plays a vital role in modern society, the electrical power outage has become a major impediment for Nigeria's development. Introduction of Solar Parks (SPs) as well as Solar and Wind-Assisted Parks (SWAPs) (i.e., parks that generate both solar and wind energy) will be a robust and environmentally friendly way of generating electricity.The goal of this research is to develop a multi-step approach - including mathematical programming - to design a capacitated network of SPs and SWAPs in South-Eastern Nigeria, taking into account geographical and demographical characteristics. Meteorological data will also be taken into consideration for preferred wind power generation. To test and validate our approach, we select as case study the state of Anambra, since this is the first state in Nigeria to embrace structural planning for its cities. Moreover, Anambra is currently depending on neighboring states for its electricity supply. We design a capacitated energy network which is powerful enough to cover almost the entire energy requirement of Anambra. The density of the network is such that the majority of households are within reasonable distance (at most 30 km) from the nearest energy park. This way the state will be self-supporting energy-wise in a sustainable way.     

The potential for wind energy in Britain

This paper discusses the prospects for the large-scale use of wind power for electricity supply in Britain. Recent economic advances in wind energy are outlined, and it is shown that on windy sites, currently-available machines are among the cheapest generating options. The results from detailed studies of wind energy resources, and of the long-term integration of wind power on the UK supply system, are then summarized. These studies are applied together in probabilistic projections of wind energy and power system costs. Results suggest that, siting permitting, the economic long-term contribution of wind energy in Britain is likely to lie in the range of 20–50% of system demand. The most critical questions for wind development now relate to institutional issues and the desirability of the source on such scales.     

Use of solar assisted geothermal heat pump and small wind turbine systems for heating agricultural and residential buildings

The main objective of the present study is twofold: (i) to analyze thermal loads of the geothermally and passively heated solar greenhouses; and (ii) to investigate wind energy utilization in greenhouse heating which is modeled as a hybrid solar assisted geothermal heat pump and a small wind turbine system which is separately installed in the Solar Energy Institute of Ege University, Izmir, Turkey. The study shows 3.13% of the total yearly electricity energy consumption of the modeled system (3568 kWh) or 12.53% of the total yearly electricity energy consumptions of secondary water pumping, brine pumping, and fan coil (892 kWh) can be met by using small wind turbine system (SWTS) theoretically. According to this result, modeled passive solar pre heating technique and combined with geothermal heat pump system (GHPS) and SWTS can be economically preferable to the conventional space heating/cooling systems used in agricultural and residential building heating applications if these buildings are installed in a region, which has a good wind resource.     

Offshore wind energy prospects

In last two years offshore wind energy is becoming a focal point of national and non national organizations particularly after the limitations of fossil fuel consumption, adopted by many developed countries after Kyoto conference at the end of 1997 on global climate change. North Europe is particularly interested in offshore for the limited land areas still available, due to the intensive use of its territory and its today high wind capacity. Really the total wind capacity in Europe could increase from the 1997 value of 4450 MW up to 40 000 MW within 2010, according the White Paper 1997 of the European Commission; a significant percentage (25%) could be sited offshore up to 10 000 MW, because of close saturation of the land sites at that time. World wind capacity could increase from the 1997 value of 7200 MW up to 60 000 MW within 2010 with a good percentage (20%) offshore 12 000 MW. In last seven years wind capacity is shallow waters of coastal areas has reached 34 MW. Five wind farms are functioning in the internal seas of Netherlands, Denmark, Sweden; however such siting is mostly to be considered as semi-offshore condition. Wind farms in real offshore sites, open seas with waves and water depth over 10 m, are now proposed in North Sea at 10–20 km off the coasts of Netherland, Denmark using large size wind turbine (1–2 MW). In 1997 an offshore proposal was supported in Netherland by Greenpeace after the OWEMES '97 seminar, held in Italy on offshore wind in the spring 1997. A review is presented in the paper of the European offshore wind programs with trends in technology, economics and siting effects.