Potential of solar energy development for water pumping in Jordan

The potential of solar energy development for water pumping in Jordan was studied. For this purpose, 10 sites were selected based on the available solar radiation data. According to the annual amount of water output, the selected sites can be divided into three different categories: the first one, which includes Taffieleh, Queira, H-4, and H-5, is considered to be “adequate” for solar water pumping. Their annual amount of water output forms about 62% of all water pumped from all the 10 sites combined. Among the four sites included in this first category, Taffieleh has the highest potential. Not only can the most annual amount of water pumped be obtained from this location, but also the largest monthly amount of water—except for the month of March—during the year. Furthermore, about 51% of the annual amount of water pumped at Taffieleh is during the summer months (May–September), when the water consumption is the highest and water pumping is a necessity. The second category, which includes Ras Muneef, Mafraq, and Hasa, is considered to be “promising”. Its water output adds up to about 29% of all water pumped from all sites. The third category, including Deir Alla, Baqura, and Wadi Yabis, is considered to be “poor”. Only about 9% of the water pumped from all sites combined can be obtained from these three locations.     

Potentials of wind energy development for water desalination in Jordan

The potential of the development of water desalination using wind energy in Jordan was studied. Eleven wind solar sites were considered. The results show that these sites can be divided, in terms of the yearly total amount of desalinated water, into three categories. One is considered favourable, which includes Ras Muneef, Mafraq, and Aqaba. Their water production adds up to about 75% of all water produced from all 11 sites combined. Others are considered to be promising (about 24% in total), which include H-5, Irbid, and Ma'an. The rest of sites considered are found to be very poor, which include H-4, Amman, Queen Alia Airport, Shoubak, and Deiralla, with traces of water produced (less than 1%). © 1998 John Wiley & Sons, Ltd.     

Using hydropower to complement wind energy: a hybrid system to provide firm power

This paper presents a theoretical study of how wind power can be complemented by hydropower. A conceptual framework is provided for a hybrid power station that produces constant power output without the intermittent fluctuations inherent when using wind power. Two hypothetical facilities are considered as case studies. One of them is a hydropower plant located on the “Presidente Benito Juarez” dam in Jalapa del Marques, Oaxaca, Mexico. The other hypothetical facility is a wind farm located near “La Venta”, an area in Juchitan, Oaxaca, Mexico. The wind–hydro-power system is a combined wind and hydro power plant in a region that is rich in both resources. The model shows that the hybrid plant could provide close to 20 MW of firm power to the electrical distribution system. On a techno-economic basis, we obtain the levelized production cost of the hybrid system. Taking into account two different discount rates of 7% and 10%, figures for levelized production cost are developed.     

Performance assessment of a solar still using blackened surface and thermocol insulation

Fluoride contaminated drinking water is a severe problem in many parts of the world because of fluoride-related health hazards, which are considered to be a major environmental problem today. The present work is aimed at utilizing solar energy for removal of fluoride from drinking water by using a “solar still”. Also tests have been conducted with the “solar still” to find out hourly output rate and “still efficiencies” with various test matrixes. It is observed that the distillate from “solar still” showed a fluoride reduction of 92–96%. Further, the efficiency of “solar still” got increased by 11% when capacity of water in the solar basin was raised from 10 to 20 L. Upon suitable modification of the solar basin with appropriate base liner and insulation, this efficiency of the “solar still” is found to be further increased by 6% with a 20 L basin capacity.     

Wind generator potentiality in Somalia

The wind data of several measurement sites in Somalia have been analysed in order to characterize the wind potentiality in relation to the type of wind generators; these have been defined by a simple model of the system output. The relation between machine and local frequency distribution as to energy extraction can be defined by a parameter (“site effectiveness”), which is maximized by a suitable combination of the rated and cut-in wind speed. On this basis it is shown that Somalia is characterized by wind frequency distributions that can be exploited in the best way by relatively slow rather than fast wind machines.     

“Energy Tower” combined with pumped storage and desalination: Optimal design and analysis

The “Energy Tower” (ET) is a power plant project which uses hot dry air and seawater to produce electricity. An optimized design of a system that is a combination of an ET, pumped storage and seawater desalination plant is considered. A model set covering each subsystem, and results of the optimized design for a project in the area of Eilat are presented. The additional benefit from combining the systems comes from an efficient use of the energy in the brine water coming from the desalination process, and from using pumped storage in an unconventional way. The benefits of the combined system lead to an increase of 14% in the annual net profit, compared to the sum of profits from optimally designed stand-alone systems.     

The capacity credit of wind power: A theoretical analysis

A probabilistic model of capacity credit (or value) is constructed for wind power in an electricity grid, The model-which is initially based on the assumptions that electricity supply, electricity demand and the output of a system of aerogenerators are Normally distributed and that the conventional power plant in the grid comprises units of identical capacity—provides simple analytical expressions for four different concepts of capacity credit and elucidates the qualitative differences between them.Two of these concepts of wind power capacity credit, the “equivalent conventional capacity” and the “equivalent firm capacity”, are then studied in more detail by introducing a much more realistic probability distribution of wind power output than the Normal distribution and by calculating the Loss of Load Probability. For small penetrations of wind power into the grid, the capacity credit is approximately equal to the average wind power output, while for large penetrations the credit tends to a limit which is determined by the probability of zero wind power and the conventional plant characteristics.     

Optimization of a wind-power fuel-cell hybrid system in an autonomous electrical network environment

Stability considerations associated with intermittency prevent high wind energy penetration in small electrical networks. The case of the islands of the Aegean is presented. [Ntziachristos L, Kouridis C, Samaras Z, Pattas K. A wind-power fuel-cell hybrid system study on the non-interconnected Aegean islands grid. Renewable Energy 2005;30(10):1471–1487] proposed a wind turbine(WT)–fuel-cell hybrid as a means to store wind energy and increase penetration in these islands. The effect of network restraints was, however, not included in that study. Simulation results including network restrictions prove that when network restrictions are relatively “strict”, hybridizing a WT using the scheme presented in the same paper will indeed increase the WT's energy output. However, in the case of “lenient” network restrictions, that hybridization scheme will in fact decrease the WT's energy output. Moreover, the system configurations presented that paper could not achieve financial viability at current electricity prices due to high capital costs. Two alternative operating principles for the hybrid system are presented in this study. These operating principles significantly improve the hybrid system's energy performance even under “lenient” network restrictions. In some cases, these operating principles manage to yield hybrid systems that are financially viable assuming current electricity prices.     

The Fundamentals of Integrating “the commons”: Application as community tissue or urban implant

Clarifying the means by which we define and shape the commons, can become the platform from which we can seek to achieve community-scale integration in service to principles of sustainability. This paper presents the formulation of energy-related environmental variables — sun, light, wind and water — in “envelope form” for purposes of modeling alternative integrative patternings of communities as “tissue on the land”. Such modeling yields prototype designs of urban districts, urban blocks and/or individual buildings whose designs capitalize on passive energy manipulation as a “first order” response, thus structuring strategies for the integration of efficient “second order” metabolic systems which together provide the technical base for energy-related resource management.     

Low wind speed turbines and wind power potential in Minnesota, USA

Wind power development in Minnesota largely has been focused in the “windy” southwestern part of the state. This research evaluates the additional power that potentially could be generated via low wind speed turbines, particularly for areas of the state where there has been comparatively little wind energy investment. Data consist of 3 years (2002–2004) of wind speed measurements at 70–75 m above ground level, at four sites representing the range of wind speed regimes (Classes 2–5) found in Minnesota. Power estimates use three configurations of the General Electric 1.5-MW series turbine that vary in rotor diameter and in cut-in, cut-out, and rated speeds. Results show that lower cut-in, cut-out, and rated speeds, and especially the larger rotor diameters, yield increases of 15–30% in wind power potential at these sites. Gains are largest at low wind speed (Class 2) sites and during the summer months at all four sites. Total annual wind power at each site shows some year-to-year variability, with peaks at some sites partially compensating for lulls at others. Such compensation does not occur equally in all years: when large-scale atmospheric circulation patterns are strong (e.g., 2002), the four sites show similar patterns of above- and below-average wind power, somewhat reducing the ability of geographic dispersion to mitigate the effects of wind speed variability.     

GIS-based environmental assessment of wind energy systems for spatial planning: A case study from Western Turkey

Increasing population and life standards causes fossil fuel consumption to increase. Due to this increasing consumption, fossil fuels are being depleted rapidly. In addition to rapid exhaustion, another important problem associated with fossil fuels is that their consumption has major negative impacts on the environment. Therefore, many countries around the world have included renewable energy systems (RES) in their future energy plans so that they can produce reliable and environmentally friendly energy. Parallel to this trend, various RES have been identified and recently integrated into the current energy network of Turkey as well. However, it should be recognized that renewable energy resources are not fully environmentally safe. Different RES are associated with different environmental impacts. In planning the future energy development of a country, evaluation of renewable energy resources potentials together with their associated environmental impacts is critical. The aim of this study is to create a decision support system for site selection of wind turbines using Geographic Information System (GIS) tools. Wind energy potential and environmental fitness/acceptability are used as decision criteria for the site selection process. Potential environmental impacts of wind generation are identified in accordance with Turkish legislations and previous studies; and represented as fuzzy objectives of the decision problem. Wind potential map of Turkey generated by General Directorate of Electrical Power Resources Survey and Development is used to identify economically feasible locations in terms of wind energy generation. A study area composed of Usak, Aydin, Denizli, Mugla, and Burdur provinces in Turkey is selected and divided into 250 m × 250 m grids. Each grid represents an alternative location for a wind turbine or group of wind turbines. Fuzzy environmental objectives such as “Acceptable in terms of noise level”, “Acceptable in terms of bird habitat”, “Acceptable in terms of safety and aesthetics” and “Safe in terms of natural reserves” associated with wind turbines are identified based on previous research and each of these objectives are represented by a fuzzy set. Individual satisfaction degree of each of these environmental objectives for each grid is calculated. Then these individual satisfactions are aggregated into an overall satisfaction degree using various aggregator operators such as “and”, “or”, and “order weighted averaging.” Thus, an overall satisfaction degree of all the environmental objectives is obtained for each grid in the study area. A map of environmental fitness is developed in GIS environment by using these overall satisfaction degrees. Then this map is utilized together with the wind potential map of Turkey to identify both potentially and environmentally feasible wind turbine locations within the study area.     

Communication matters

If ‘saving the earth’ was a cherished common goal, the following headlines opposing wind farm developments in remote parts of Scotland would find fewer readers: “Experts fear wind-farm could hit TV reception”, “Wind farm plan sparks blaze fears” or just “Scenic Sabotage”. To simply ignore these dramatic appeals could have dire consequences. Halo Energy consultants, Ralph Kappler and Michael Hay, who carried out surveys on local opinion to wind farm development in Scotland for the University of Aberdeen, emphasise the increasing need for sector driven and joined-up communications.     

Variance analysis of estimates and measurements of terrestrial heat flow

A components-of-variance-analysis is applied to compare heat flow estimates with heat flow measurements. Three types of heat flow data are analysed; they are: “between depth interval within well” variances, “between well site-within region” variances and “between region” variances. “Between depth interval-within well” heat flow variances are typically greater for estimates than for measurements, implying a greater unsystematic uncertainty with the interval heat flow estimates as compared to the interval measurements. “Between well site-within region” variances of heat flow are about the same, or in some cases less, for groups of estimated data as compared with groups of measured data. Therefore unsystematic uncertainties for good heat flow estimates at sites within a region should compare favourably with similar uncertainties for heat flow measurements at sites within a region. Both the “F” test and the “between region” heat flow variances suggest that estimates and measurements of heat flow can reasonably differentiate between regions of different heat flow.Some of the estimated and measured data groups are from the same region. The very limited number of heat flow estimates and measurements available indicate that the mean of estimates and the mean of deep measurements in the northern Colorado Plateau are in close agreement. While this suggests the possibility that a number of carefully calculated heat flow estimates may reasonably define the mean heat flow for a region, more data in other regions will be needed to support the concept.     

Determining typical weather for use in solar energy simulations

Predicting the performance of a solar energy system by using simulation methods requires weather data input for the locality involved. The present paper describes a method of analyzing an optional number of years of weather data for a chosen month resulting in a “typical week” which is characterized in terms of solar radiation, ambient dry bulb temperature and wind speed. The “typical week” is allowed to vary in length between 5 and 10 days in the analysis in order to enable selection of a period that best represents a given month according to specified criteria.Verification of the method by comparative computer analysis was performed using two forms of weather data as inputs to the solar energy program “TRYNSYS”. The averaging method when compared to the “typical” weather method resulted in differences of less than 7 per cent.The use of “typical” weather appears to give results at least comparable with more established methods while at the same time providing a broad spectrum of the weather typical of an area. The use of “typical” weather can result in savings in computer time.     

Solar-assisted absorption heat pumps feasibility

An absorption system can be used for space cooling as well as for space heating. This dual purpose may be achieved by using the system as heat pump in wintertime. Absorption heat pump heating may be an interesting alternative, particularly for countries where there is a shortage of electric power.When an absorption unit is used as heat pump, its mode of operation is not modified: the internal temperatures of the cycle are only raised. Commercially available LiBr units were tested as heat pumps. COP and heating capacity were considered as a function of cold source temperature for different temperatures of the useful heat. The COP arrived at 1.7, which must be considered a high value for a thermally driven heat pump.Simulations were carried out in order to compare the performance of “conventional” solar, solar assisted heat pump and the combined series system under two different climate conditions. The series system showed performance 25–75 per cent better than “conventional” solar alone.     

Decision making in energy planning: the ELECTRE multicriteria analysis approach compared to a FUZZY-SETS methodology

Every planning activity generally requires to make some choices. After a preliminary analysis of the sector under examination, a forecast of trends of input–output items, the planner must define an action plan voted to arrange all the strategies and specific interventions able to fit demand and supply during the planned time. The redaction of an action plan implies a strong effort in order to synthesize either suggestions coming from the analysis phases either all the constraints linked to technical choices. In the same time, a large number of “external” variables plays a role in orienting decision making. Some of these can be handled by numerical models (economic cost-benefit analyses, market penetration strategies, environmental impacts). Other aspects, concerning social and cultural impact, political drawbacks, aesthetic aspects, etc., can be analysed only in a qualitative way, or are subjected to a not-objective judgement. This paper aims of introducing a methodological tool able to “organize” and “synthesize” the large set of variables coming from several specific judgements (or assessments) helping the “decision maker” to read the complex problem, understand it and make choices. Previous works of the authors have presented possible applications of “multicriteria-analysis”. In particular, the ELECTRE methods family, (Roy, B., Me´thodologie multicrite`re d'aide a` la de´cision, Economica, coll. ‘‘Gestion', Paris, 1985) will be presented under the point of view of energy planning application. It consists in a “flexible” ranking method which takes into account the uncertainties of all the specific assessments, the qualitative nature of some indexes, the weight of the preferences or willingness systems of the decision maker. On the other hand, similar results can be obtained through the application of fuzzy sets theory (Zimmermann, H. J., Fuzzy set Theory and its Application. Kluver Academic Publisher, 1987). A decision making support method, based on fuzzy logic is here tested and compared to the previous one. A case study developed by authors will show differences among these two different approachs. It is focused on the development of a renewable energy diffusion strategies plan. Advantages and drawbacks of both methods will be explored and some suggestions will be proposed.     

Dimensioning of the solar heating system in the zero energy house in Denmark

The paper describes the project for a Zero Energy House constructed at the Technical University of Denmark. The house is designed and constructed in such a way that it can be heated all winter without any “artificial” energy supply, the main source being solar energy. With energy conservation arrangements, such as high-insulated constructions (30–40 cm mineral wool insulation), movable insulation of the windows and heat recovery in the ventilating system, the total heat requirement for space heating is calculated to 2300 kWh per year. For a typical, well insulated, one-storied, one-family house built in Denmark, the corresponding heat requirement is 20,000 kWh. The solar heating system is dimensioned to cover the heat requirements and the hot water supply for the Zero Energy House during the whole year on the basis of the weather data in the “Reference Year”. The solar heating system consists of a 42 m² flat-plate solar collector, a 30 m³ water storage tank (insulated with 60 cm of mineral wool), and a heat distribution system. A total heat balance is set up for the system and solved for each day of the “Reference Year”. Collected and accumulated solar energy in the system is about 7300 kWh per yr; 30 per cent of the collected energy is used for space heating, 30 per cent for hot water supply, and 40 per cent is heat loss from the accumulator tank. For the operation of the solar heating system, the pumps and valves need a conventional electric energy supply of 230 kWh per year (corresponding to 5 per cent of the useful solar energy).     

CO2 mitigation costs for new renewable energy capacity in the Mexican electricity sector using renewable energies

Carbon dioxide mitigation costs for the Mexican power sector are calculated in order to compare the business as usual (BAU) scenario, based on natural gas capacity growth, to a transition scenario where electricity generation growth using natural gas after 2007 is replaced by renewable energies (solar, wind, hydro and biomass). The mitigation costs are obtained using the following parameters: natural gas price, discount rate and technological progress. The latter is expressed in terms of the anticipated decrease in capital costs, as reported in electricity generation technological literature. Our results show that when technological progress is considered, CO₂ mitigation costs decrease rapidly from 14 $/tCO₂ (in this paper $ express 1997 US dollars and t means metric tons) to zero when the price of natural gas nears 2.68 $/GJ, (for some readers, it can be useful to know that 1.0 US$1997/GJ is 1.19 US$2001/MMBTU) which is almost the same as the 2002 price. This means that for middle natural gas prices a “no regrets” situation can be achieved. Our results also show that for prices higher than 2.80 $/GJ, the incorporation of the technological progress parameter transforms the transition scenario into a “no regrets” scenario for all the discount rate values considered in this study.     

Research on wind turbine rotor models using NACA profiles

In this study, rotation rates and power coefficients of miniature wind turbine rotor models manufactured using NACA profiles were investigated. For this purpose, miniature rotor models with 310 mm diameter were made from “Balsa” wood. When all properties of rotor models were taken into account, a total of 180 various combinations were obtained. Each combination was coded with rotor form code. These model rotors were tested in a wind tunnel measurement system. Rotation rates for each rotor form were determined based on wind speed. Power coefficient values were calculated using power and tip speed rates of wind. Rotor models produced a rotation rate up to 3077 rpm, with a power coefficient rate up to 0.425. Rotor models manufactured by using NACA 4412 profiles with 0 grade twisting angle, 5 grade blade angle, double blades had the highest rotation rate, while those manufactured by using NACA 4415 profiles with 0 grade twisting angle, 18 grade blade angle, 4 blades had the highest power coefficient.     

Outdoor rating conditions for photovoltaic modules and systems

Historically, flat-plate photovoltaic modules have been given a “peak-watt” rating indicating the power generated under 1000 W/m² global irradiance at a standard temperature. However, questions have arisen regarding the direct-normal irradiance, ambient or cell temperature, and wind speed (when it is specified) that should be used for evaluating the performance of flat-plate and concentrator modules. By studying the conditions that are observed when the global irradiance on a 2-axis-tracked surface is 1000 W/m², our analysis provides an objective, quantitative basis for the choice of the “peak-watt” rating conditions for both types of collectors. These observed conditions are consistent with commonly used values of 850 W/m² for direct-normal irradiance and 20°C for ambient temperature. Evidence is given that wind speed should be increased from the commonly used 1 m/s to a more frequently observed 4 m/s.