[en] During the last 3 yr (1999-2002) a significant increase in the utilization of the existing wind power has taken place in Greece, after a long period (1993-1998) of inactivity. Unfortunately, the largest part of new scheduled installations is concentrated in a few geographical regions, in an attempt to take advantage of the existing electrical network capabilities and the acceptable infrastructure situation. This significant concentration of very large size wind turbines, rapidly installed in a few geographical areas, led to serious reactions from the local population, which in some cases even led to the complete cancellation of the wind power projects. In this context, an extensive study is conducted, concerning the public attitude towards wind energy applications, in several island and mainland Greek territories possessing high wind potential and investment interest. The results obtained significantly reveal acceptance of the existing wind parks, being, however, rather against new installations. More specifically, in the Greek islands the public attitude is clearly supportive, while in the Greek mainland the public attitude is either divided or definitely against wind power applications. The most troublesome outcome of this survey is the existence of a specific minority that is strongly against wind energy applications, disregarding any financial benefits. Among the primary conclusions drawn, one may underline the necessity of additional public information regarding the wind energy sector

[en] Hydropower has by far been the most mature renewable energy resource used for electricity generation in our planet. Recently, the investors' interest was whipped up by the mass development of small hydropower (SHP) stations, as they are the most prosperous for additional hydropower penetration in developed electricity markets. In Greece, the increasing interest for building SHP stations got off the ground since 1994. Ever since, an enormous number of requests keep piling up in the Greek Regulatory Authority of Energy and the Ministry of Development, with the object of creating new SHP stations of total capacity over 600 MW. The present work is concentrated on the systematic investigation of the techno-economic viability of SHP stations. The study is concluded by a sensitivity analysis properly adapted for the local market financial situation, in order to enlighten the decision makers on the expected profitability of the capital to be invested. According to the results obtained, the predicted internal rate of return (IRR) values are greater than 18% for most SHP cases analysed. Finally, as per the sensitivity analysis carried out, the installation capacity factor, the local market electricity price annual escalation rate and the reduced first installation cost are found to be the parameters that mostly affect the viability of similar ventures

[en] Autonomous photovoltaic systems have turned into one of the most promising ways to handle the electrification requirements of numerous isolated consumers worldwide. Such an autonomous system comprises a number of photovoltaic panels, properly connected, and a battery storage device, along with the corresponding electronic equipment. Considering the high solar potential of most Greek territories, an integrated study is conducted based on long term solar potential experimental measurements in order to determine the optimum configuration of a stand alone photovoltaic system at representative locations all over Greece. The proposed solution 'guarantees' zero load rejections for all the areas and time periods examined. For this purpose, a fast and reliable numerical code 'PHOTOV-III' has been used. The algorithm provides analytical results concerning the energy autonomy and the operational status of the autonomous system components. Besides, the optimum panel tilt angle, minimizing the first installation cost of a small photovoltaic system, is predicted. Finally, by introducing available financial aspects, it is possible to determine the optimum system dimensions on a minimum first installation cost basis. According to the results obtained, an autonomous photovoltaic system can definitely contribute to solution of the urgent electrification problem of remote consumers spread throughout Greece, also improving their life quality level

[en] A vital problem encountered in Greek islands within the Aegean Archipelago is insufficient electricity generation. Wind generated electricity appears to be a fiscally viable solution, as the area has excellent wind potential. Yet despite the technological improvement, the penetration of substantial wind power to autonomous electrical grids is still limited, mainly due to existing technical barriers. One of the most interesting autonomous electrical network cases is the island of Crete. Here, with an excellent wind potential, about 180 wind turbines of 120 MW total installed rated-capacity are in operation or under construction. However, even in this relatively strong electrical system, grid instability and mismatching of supply and demand have led to significant wind energy rejection. This 'spilt' wind power corresponds to an annual financial loss of income of 30,000 E per MW of wind power installed. The present study seeks an integrated methodology with pumped-hydro storage for maximizing the contribution of wind energy in the Crete electricity supply. In addition, the objective is to improve grid stability. An analysis of the wind-hydro electricity production cost is presented and compared with the corresponding operational cost of the existing thermal power plants. (Author)

[en] An integrated, time-depending computational frame concerning the economic behaviour of wind energy applications in Greece is developed. This frame is accordingly used to analyse the local wind energy market situation during the last 15 years. According to the results obtained, one may - on pure economic basis - explain the evolution of wind energy applications in the three major Greek sections presenting interest for wind power stations construction, i.e. the small medium sized Aegean Archipelago islands, the Crete Island and the windy sites of mainland. Furthermore, the proposed model predicts no additional wind parks in the Aegean Sea Islands and Crete. The only solution to this negative evolution is the development of additional energy storage systems, e.g. wind-hydro stations. On the contrary, the Greek mainland opportunities in selected windy sites are more encouraging under the precondition of strengthening the existing electricity transportation networks and properly handling the increasing public annoyance towards new large wind turbines erection in relatively few closed areas. (author)

[en] Wind parks operating in autonomous island grids, such as those encountered in the Aegean Archipelago, face considerable wind energy curtailments, owed to the inability of local electricity networks to absorb the entire wind energy production. On the other hand, plans promoting the natural gas-based electricity generation in big islands (such as Crete) question the future of wind energy. To recover wind energy curtailments and benefit from the introduction of natural gas, the adoption of compressed air energy storage (CAES) systems suggests an appreciable energy solution. Furthermore, to improve the economic performance of the proposed system, it is decided that guaranteed energy amounts should be delivered to the local grid during peak demand periods. In an effort to obtain favourable negotiation conditions - for the selling price of energy delivered - and also improve the economic performance of the system, a dual mode CAES operation is currently examined. Proceeding to the economic evaluation of dual mode CAES configurations that ensure maximum wind energy recovery, the feasibility of the proposed system may be validated. Lower electricity production costs and considerable reduction of fuel consumption achieved - in comparison with the requirements of conventional peak demand power units - illustrate the system's advantages. (author)

[en] Hydropower is the most widely used renewable energy source worldwide, contributing almost with 18.5% to the fulfillment of the planet electricity generation. However, most locations in Europe appropriate for the installation of large hydro power stations have already been exploited. Furthermore, there is a significant local communities' opposition towards new large power stations; hence, small hydro power stations remain one of the most attractive opportunities for further utilization of the available hydro potential. Greece and more precisely the country's mainland possesses a significant hydro-power potential which is up to now only partially exploited. In parallel, a large number of private investors have officially expressed their interest in creating small hydro power stations throughout the country, encouraged by the significant Greek State subsidy opportunities for renewable energy applications. However, up to now a relatively small number of projects have been realized, mainly due to decision-making problems, like the administrative bureaucracy, the absence of a rational national water resources management plan and the over-sizing of the proposed installations. Certainly, if the above problems are suitably treated, small hydro-power plants can be proved considerably profitable investments, contributing also remarkably to the national electricity balance and replacing heavy polluting lignite and imported oil. In the context of the above interesting issues, the present study reviews in detail the existing situation of small hydropower plants in Greece and investigates their future prospects as far as the energy, economic and environmental contribution are concerned

[en] Photovoltaic (PV) applications, gaining worldwide interest during the last years, comprise a promising renewable energy based solution, able to considerably contribute to the constantly increasing energy demand of our planet. Currently, residential applications possess a considerable share of the global PV market since fiscal and practical incentives have reinforced their promotion. On the other hand, high population concentration, rapid industrialisation and economic development of urban areas all over the world have caused significant degradation of the urban air quality. In this context, the actual performance of five identical pairs of roof-top PV-panels, operating in the aggravated urban environment of Athens (from the atmospheric air pollution point of view), is currently evaluated. For this purpose, a series of systematic experimental measurements is conducted within a certain time period and the influence of different dust deposition densities on the energy yield and the economic performance of the small power station is estimated. According to the results obtained, the presence of dust considerably affects the PV-panels' performance since even a relatively small dust deposition density (∼1 g/m²) may result in remarkable energy losses corresponding almost to 40 EUR/kW_p on an annual basis. (author)

[en] Greek islands cover their continuously increasing electricity demand on the basis of small autonomous thermal power stations. This electrification solution is related with increased operational cost and power insufficiency, especially during summer. On the other hand, the stochastic behaviour of the wind and the important fluctuations of daily and seasonal electricity load in almost all Greek islands pose a substantial penetration limit for the exploitation of the high wind potential of the area. In this context, the present study is concentrated on developing an integrated methodology which can estimate the maximum wind energy contribution to the existing autonomous electrical grids, using the appropriate stochastic analysis. For this purpose one takes into account the electrical demand probability density profile of every island under investigation as well as the operational characteristics of the corresponding thermal power stations. Special attention is paid in order to protect the existing internal combustion engines from unsafe operation below their technical minima as well as to preserve the local system active power reserve and the corresponding dynamic stability. In order to increase the reliability of the results obtained, one may use extensive information for several years. Finally, the proposed study is integrated with an appropriate parametrical analysis, investigating the impact of the main parameters variation on the expected maximum wind energy contribution

[en] After a long stagnating period during the second half of the 1990s, the market of wind energy in Greece was described by remarkable but unstable growth rates that resulted in the operation of 1 GW of wind power by the end of 2009. Still though, penetration of wind energy is not the one anticipated. On the other hand, national targets regarding the Renewable Energy Sources' (RES) contribution and existence of excellent wind potential areas across Greece challenge new wind energy investments. Acknowledging the unsteady development rates of wind power in Greece, efficiency of the State support mechanisms is currently investigated. Based on an analytical evaluation model, the investigation undertaken is extended to provide a detailed cost-benefit analysis of several wind energy case studies, including mainland and island applications as well as comparison with both conventional power stations and photovoltaic plants. For this purpose, the financial support provided by the State is directly compared with benefits accruing from the operation of wind parks, considering also the avoidance of social costs deriving from thermal power stations. Based on the results obtained, the beneficial characteristics of wind energy applications for the Greek society are clearly demonstrated, especially in the case of non-interconnected island grids. - Research highlights: → Since the mid-1990s, growth of wind power capacity in Greece has been unstable. → As a result, integration of wind energy is not the one anticipated. → Considering the situation, efficiency of State support mechanisms is evaluated. → An analytical cost-benefit model is developed and applied to various case studies. → Benefits from wind energy, especially in island regions, are designated.