Renewable and Sustainable Energy Reviews 16 (2012) 2558–2565 Contents lists available at SciVerse ScienceDirect Renewable and Sustainable Energy Reviews j ourna l ho me pa ge: www.elsevier.com/locate/rse r The role of pumped storage systems towards the large scale wind integration in the Greek power supply system G. Caralis ∗ , D. Papantonis, A. Zervos National Technical University of Athens, School of Mechanical Engineering, Fluids Session, 15780 Zografou, Athens, Greece a r t i c l e i n f o Article history: Received 29 April 2011 Accepted 29 January 2012 Available online 20 March 2012 Keywords: Pumped storage systems Greek power system Large wind integration Tariffs a b s t r a c t In the recent years, the debate on the necessity of pumped storage systems in the Greek power supply system has started. In the current decade, the Greek power system will gradually try higher RES pene- tration, mainly due to wind energy and photovoltaics integration. Variability of wind and PV generation and the current structure of the Greek power system introduce technical constraints, which should be taken into consideration in the forthcoming large scale RES integration. This paper examines the ability of the Greek power system to absorb renewable power and the necessity of pumped storage systems. The feasibility of pumped storage systems is discussed in three different scenarios of wind–photovoltaics integration. Results show that for the gradual increase of variable output RES, pumped storage systems are required, but the feasibility of pumped storage systems is not proved in the intermediate scenarios of RES integration. © 2012 Elsevier Ltd. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2558 2. Current situation and prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2559 3. Simulation of the Greek power supply system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2559 3.1. Basic concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2559 4. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2561 5. Exploitation of wind energy surplus in pumped storage systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2562 5.1. Basic principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2562 5.2. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2562 5.3. Tariffs for hydro turbine production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2563 5.4. Complementary conventional power for pumping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2564 6. Conclusions and discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2564 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2564 1. Introduction Wind energy represents a rapid growth worldwide and is the most commercially and economically competitive renewable energy source. Several power systems in the world are supplied and will be supplied in the near future by large fractions of wind energy. As regards the wind share at a national level, Denmark, Spain and Portugal are leaders with 24%, 14.4% and 14% of annual contribution respectively [1]. Denmark achieves this rate, thanks to the large interconnections with other major European grids, while ∗ Corresponding author. E-mail address: gcaralis@mail.ntua.gr (G. Caralis). Portugal, due to the parallel operation of several hydroelectric sta- tions. The autonomous power system of Crete represents a 14% annual wind energy contribution which could be considered as an upper technical limit in such cases [2]. In Greece, the achievement of national targets will be based primary on wind farms development, and secondarily on pho- tovoltaics, because the former is considered as a more mature, efficient and economic technology in relation to the latter. Despite their high cost, photovoltaics contribute in the summer midday peak demand, and provide the power system with beneficiary dis- tributed generation very close to the consumption. The national target for the penetration of RES is set at 40% of gross electricity consumption by 2020 [3]. According to the national action plan [4] the achievement of this target will be reached with 7500 MW of 1364-0321/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.rser.2012.01.068