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- Bekele, Getachew, 1958-
(författare)
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Study into the Potential and Feasibility of a Standalone Solar-Wind Hybrid Electric Energy Supply System
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The tendency to use renewable energy resources has grown continuouslyover the past few decades, be it due to fear over warnings of globalwarming or because of the depletion and short life of fossil fuels or evenas a result of the interest which has developed among researchers doingscientific research into it. This work can be considered as joining any ofthese groups with an objective of giving electric light to the poorpopulation living in one of the poorest nations in the world.The aim of the work is to investigate supplying electric energy fromsolar-wind hybrid resources to remotely located communities detachedfrom the main grid line in Ethiopia. The communities in mind are one oftwo types; the first is the majority of the poor population residing in thecountryside; and the other is people relocated by the Government fromthe over used and dry regions to relatively productive and fertile ones inline with the long-term poverty reduction plan.The work was begun by investigating wind energy and solar energypotentials at four geographically different locations in Ethiopia bycompiling data from different sources and analyzing it using a softwaretool. The locations are Addis Ababa (09:02N, 038:42E), Mekele (13:33N,39:30E), Nazret (08:32N, 039:22E), and Debrezeit (8:44N, 39:02E).The results related to wind energy potential are given in terms of themonthly Average wind speed, the wind speed probability densityfunction (PDF), the wind speed cumulative density function (CDF), thewind speed duration curve (DC), and power density plots for all fourselected sites. According to the results obtained through the analysis, thewind energy potential, even if it is not exceptional, is irrefutably highenough to be exploited for generating electric energy.The solar energy potential, based on sunshine duration data collectedover a period of 7 - 11 years and radiation data obtained from differentsources, has been calculated using regression coefficients specific to thesites in question. Based on the sunshine duration data, the monthlyaverage daily sunshine amount for each of the places has also beencomputed and given in a form of plot. Through additional work on theresults of the calculations, the solar energy potential has been given inthe form of solar radiation plots for each of the selected sites. Asexpected, the results indicated an abundance of solar energy potential.It is based on the promising findings of these two energy resourcepotentials, wind and solar, that the feasibility study for a standalonesolar-wind hybrid energy supply system has proceeded, targeting thecommunity mentioned earlier. The hybrid system consisted of Windturbine, Photovoltaic panel, diesel generator and a bank of batteries, witha power conditioning converter included in the system.The hybrid standalone supply system is intended to provide electricity toa model community of 200 families with five to six family members ineach. The community is equipped with a primary load, a deferrable load,a community school and a health post. An electric load which includeslighting, water pumping, a radio receiver, and some clinical equipmenthas been suggested. Hybrid Optimization Model for ElectricRenewables, HOMER, software has been used for the analysis. Theaverage wind speed and average solar radiation calculated from the datafor all of the selected sites has been used to input into the software.The hybrid system design is approached in three different ways. The firstapproach is to include within the hybrid system those components whichare locally available, without giving special attention to their efficienciesand proceed with the design work. The second approach is tothoroughly search the market for the best and most efficienttechnological products and to select the best components for theanalysis. A third approach considered in an attempt of cost minimizationis to see if a self-contained type of design can be a better solution. Whatthis means is every household will have its own supply system that mayconsist of any combination of PV and wind turbine including converter,battery and charge controller.After running the simulations, lists of power supply systems have beengenerated, sorted according to their net present cost. Sensitivity variables,such as range of wind speeds, range of radiation levels and diesel pricehave been defined as inputs into the software and the optimizationprocess has been carried out repeatedly for the sensitivity variables andthe results have been refined accordingly.
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| 2. |
- Pitz-Paal, Robert, et al.
(författare)
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Concentrating solar power in Europe, the Middle East and North Africa: a review of development issues and potential to 2050
- 2012
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Ingår i: Journal of Solar Energy Engineering, Transactions of the ASME. - : ASME International. - 1528-8986 .- 0199-6231. ; 134:2, s. Article Number: 024501-
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Forskningsöversikt (refereegranskat)abstract
- This paper summarizes the findings of a study undertaken by the European Academies Science Advisory Council to evaluate the development challenges of concentrating solar power (CSP) and its consequent potential to contribute to low carbon electricity systems in Europe, the Middle East and North Africa (the MENA region) to 2050. The study reviewed the current status and prospective developments of the four main CSP technology families, and identified prospective technical developments, quantifying anticipated efficiency improvements and cost reductions. Similarly, developments in thermal energy storage were evaluated, and the role and value of CSP storage in electricity systems were examined. A key conclusion was that as the share of intermittent renewables in an electricity system increases, so does the value of thermal energy storage in CSP plants. Looking ahead, the study concludes that CSP should be cost competitive with fossil-fired power generation at some point in the 2020's provided that commercial deployment continues at an increasing rate, and through support mechanisms that incentivise technology development. Incentive schemes should reflect the real value of electricity to the system, and should ensure sufficient transparency of cost data that learning rates can be monitored. Key factors which will determine CSP's contribution in Europe and the MENA region over the period to 2050 are generating costs, physical constraints on construction of new plants and transmission, and considerations of security of supply. The study makes recommendations to European and MENA region policy makers on how the associated issues should be addressed.
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