Volume 6 hydro power 6 11 – evolution of hydropower in spain

Volume 6 hydro power 6 11 – evolution of hydropower in spain Volume 6 hydro power 6 11 – evolution of hydropower in spain Volume 6 hydro power 6 11 – evolution of hydropower in spain Volume 6 hydro power 6 11 – evolution of hydropower in spain Volume 6 hydro power 6 11 – evolution of hydropower in spain

6.11 Evolution of Hydropower in Spain A Gil, Hydropower Generation Division of Iberdrola, Salamanca, Spain F Bueno, University of Burgos, Burgos, Spain © 2012 Elsevier Ltd All rights reserved 6.11.1 6.11.1.1 6.11.1.2 6.11.1.3 6.11.1.4 6.11.1.5 6.11.2 6.11.2.1 6.11.2.2 6.11.2.2.1 6.11.2.2.2 6.11.2.2.3 6.11.2.3 6.11.2.3.1 6.11.2.3.2 6.11.2.4 6.11.2.4.1 6.11.2.4.2 6.11.2.4.3 6.11.2.5 6.11.2.5.1 6.11.2.5.2 6.11.3 6.11.4 References Hydroelectric Power in Spain Electric Power and Hydroelectric Power The Strategic Importance of Hydroelectric Power Hydrology, River Network, and Hydroelectric Development Power Plants and Main Developments Producing Companies Evolution of Schemes and First Developments Periods in the Evolution of Development The 1890–1940 Period First steps of electricity in Spain The electricity sector in the first decades of the twentieth century Main hydropower developments The 1940–60 Period The electricity after the civil war Main hydropower developments The 1960–75 Period The electricity sector The golden age of dam engineering in Spain Main hydropower developments The Last Three Decades The electricity sector Main hydropower developments A Representative Case: The Duero System and Its Evolution The Future of Hydroelectric Power in Spain 309 309 310 311 313 315 315 315 317 317 318 318 323 323 324 327 327 328 329 333 333 333 336 339 341 6.11.1 Hydroelectric Power in Spain 6.11.1.1 Electric Power and Hydroelectric Power In the first years of hydroelectric power development in Spain, at the end of the nineteenth century, it was the thermal plants that covered most of the electric power demand With the general use of alternating current and transformer stations this changed, and in the first four decades of the twentieth century hydraulic power increasingly became the main source of supply, reaching 93% of the total supply in 1936 With slightly lower values, this relevance was maintained until, from the first years of the 1960s, a large number of classic thermal power plants started operating, and nuclear power plants started from the beginning of the 1970s, which meant that in 1975 hydroelectric production was only 35% of the total In this century, the construction of combined cycle power plants and wind farms has led to the current situation, in which the installed hydroelectric power is 20% of the total and the coverage of demand is around 12% in an average year Thus, the installed hydroelectric power at the end of 2008 was 18 700 MW, from which 16 700 corresponded to the ordinary production system and 2000 to mini power plants under the special production system, over an installed total of all types of energy of 96 000 MW Combined cycle power plants are those that provide the highest installed power to the group, whereas wind power is practically the same as hydroelectric power (Figure 1) As for energy produced, hydroelectric power accounted for 26 000 GWh in 2008, from which 21 500 corresponded to the ordinary system and 4500 to the special system, compared to the nearly 295 000 GWh of the system’s total net generation (Figure 2) These values are below average, the average being 35 000 GWh, as 2008 was a dry year The pluviometric irregularity that characterizes the Spanish territory results in irregularity of superficial runoff and, as a consequence, affects hydroelectric production In 1979, good hydraulicity resulted in attaining an absolute maximum hydroelectric production of 47 473 GWh, which meant 45% of the total On the contrary, the drought in 1992 resulted in the energy produced only reaching 20 750 GWh, which meant 13% of the total Comprehensive Renewable Energy, Volume doi:10.1016/B978-0-08-087872-0.00610-7 309 310 Hydropower Schemes Around the World Combine cycle 24% Special regime 32% Hydraulics 18% Wind 17% Hydraulics 2% Other renewable 5% Nonrenewable 8% Nuclear 8% Coal 13% Fuel/gas 5% Figure Installed electrical power at the end of 2008 Combine cycle 32% Wind 11% Special regime 24% Hydraulics 8% Hydraulics 2% Other renewable 3% Nonrenewable 8% Nuclear 20% Coal 15% Fuel/gas 1% Figure Electric power production in 2008 6.11.1.2 The Strategic Importance of Hydroelectric Power Hydroelectric power has a series of important qualities that make it one of the most strategically important energies from the technical, economic, and environmental points of view From a technical point of view, due to its high degree of use in comparison to its potential, as the high efficiency of the turbines and alternators must be added to the low load losses in intake and return pipes, achieving a global efficiency of the plants between 85% and 90%, which has never been achieved in any other type of power plant From the economic point of view, the cost of the raw material is very low or nil, which affects the total generation costs very favorably From an environmental point of view, its main characteristic is in the nonemission of greenhouse gases Each hydro­ electric kWh avoids the emission of up to kg of CO2, g of SO2, and g of NOx The average production in Spain is equivalent to not emitting 35 million tons of CO2 In addition, the developments related to regulation reservoirs and pumping provide a high quantity and guarantee electrical energy supply, facilitating load curve management and the regulation of frequency and voltage They are also an installed power reserve in view of possible unavailability of other types of generation Evolution of Hydropower in Spain 311 Besides, hydroelectricity is a source of energy in itself, an important fact in a country and high energy dependence National hydroelectric production in an average year is equivalent to that obtained with billion cubic meter of natural gas, 13.2 million tons of coal from abroad, or 9.3 million tons of fuel in plants that consume these fuels The cost of avoided imports may amount to nearly €1100 million in the case of gas, €680 million in that of coal, or €1900 million in that of fuel 6.11.1.3 Hydrology, River Network, and Hydroelectric Development The average annual precipitation in Spain is around 650 mm and is characterized by its irregularity, both spatial and temporal Spatial irregularity results in two differentiated areas: Wet Spain and Dry Spain (Figure 3) Temporal irregularity of precipitations results in that for any considered period – multiannual, annual, or seasonal – the gap between the maximum and minimum values is very big To this we need to add a high evapotranspiration, which makes the average value of runoffs around one-third of precipitation From the 330 000 hm3 of precipitation, only around 110 000 become runoff All this results in the natural regulation level in Spain being close to 6–8% The current regulation level is around 40–42%, for which it has been necessary to build more than 1300 large dams Without them, economic and social development in Spain throughout the twentieth century would have been impossible (Table 1) The Spanish hydrographic network is characterized, in a first approach, by the existence of rivers with two types of structure, some with a well-developed river network (considerably long tree-shaped riverbeds with a large number of tributaries) and others with rather parallel riverbeds and short in length Among the first we find the Miño, Duero, Tajo, Guadiana, and Guadalquivir that flow into the Atlantic Ocean, and the Ter, Llobregat, Mijares, Ebro, Júcar, Turia, and Segura that flow into the Mediterranean Sea The second type are characterized for flowing in a perpendicular direction between the Cantabrian mountain ranges and the Cantabrian Sea in the north of the peninsula, and between the Andalusian mountain ranges and the Mediterranean Sea in the south The proximity of these mountain ranges with the coast give these rivers characteristics of short lengths, steep slopes, perpendicularity to the sea, and the nonconnection between them despite being close to each other (Figure 4) From the river network structuring point of view, in the first type not only has the full use of the main rivers with their tributaries been possible, but also in some cases full use of both has been possible This layout of the river network has favored a higher use of 70−300 300−600 600−900 900−1200 1200−1600 >1600 100 Figure Spatial distribution of precipitation in the peninsula 100 200 km 312 Hydropower Schemes Around the World Table Basin Norte I Norte II Norte III Duero Tajo Guadiana I Guadiana II Guadalquivir Sur Segura Júcar Ebro C I Cataluña Galicia Costa Total Natural regulation and artificial regulation by hydrographic basins Natural resources (hm3 yr−1) Natural regulation (hm3 yr−1) Natural regulation (%) Reservoir capacity (hm3) Available resources (hm3) Available resources (%) 12.689 13.881 5.337 13.660 10.883 4.414 1.061 8.601 2.351 803 3.432 17.967 2.787 916 1.146 251 742 490 44 208 18 192 771 1.819 190 10 6 1 25 28 11 11 3.040 559 122 7.667 11.135 8.843 776 8.867 1.319 1.223 3.349 7.702 772 3.937 1.837 353 6.095 5.845 1.922 228 2.819 359 626 2.095 11.012 791 31 16 49 54 47 23 35 26 83 76 64 46 12.250 426 688 1.223 18 110.116 7.219 56.063 39.175 41 Figure Spanish hydrographic basins Evolution of Hydropower in Spain 313 some of the tributaries, fed by high and medium-height mountains, than those of the main rivers, whose middle sections are less steep and whose use has been destined to irrigation In the rivers of the second group, hydroelectric use has followed classic steep development schemes Hydroelectric development of the rivers in Spain has been conditioned by competition with other uses: that of supply and especially that of irrigation Currently, 70–75% of the consumptive uses of water are destined to irrigation, which occupy the center of the Atlantic river basins and the lower sections of the Mediterranean rivers, with the consequential need of regulation reservoirs at the headwaters of its tributaries, on mountain fringes The development of irrigation began in the early twentieth century, at the same time as the origins of hydroelectric development, being direct competitors in some lands 6.11.1.4 Power Plants and Main Developments There is a great variety of hydroelectric plants, both regarding the size and the facilities characteristics In 2004, there were more than 1500 plants, including mini power plants under the special system There were nearly 900 power generation units under the ordinary system There are five power stations with more than 500 MW and 21 with more than 200 MW, which represent more than half the installed power Another 14 power stations exceed 100 MW and represent 12% of the power; those that exceed 50 MW represent 14% and those with less than 50 MW, including mini power plants, the rest (Table and Figure 5) The largest plants are those of Aldeadávila I and II, with 1243 MW, Jose M de Oriol with 933 MW, Cortes-La Muela with 915 MW, Villarino I and II with 810 MW, and Saucelle I and II with 520 MW The first, fourth, and fifth are located in the Duero System, the second in the Tajo river, and the third in the Júcar river Table 100 MW Hydroelectric power plants in Spain with an installed capacity of more than Hydro plant Turbining capacity River Aldeadávila I and II José María Oriol Cortes – La Muela Villarino Saucelle I and II Estangento – Sallente Cedillo Tajo de la Encantada Aguayo Mequinenza Puente Bibey San Esteban Ribarroja Conso Belesar Valdecañas Moralets Guillena Bolarque I and II Villalcampo I and II Castro I and II Azután Los Peares Ricobayo I and II Tanes Frieira Torrejón Salime Cofrentes Cornatel Tavascán Superior Castrelo Gabriel y Galán Canelles Cíjara I and II 1.243 934 915 825 520 451 500 360 362 324 316 265 263 270 258 250 221 210 246 227 194 200 168 328 126 154 133 160 124 132 120 130 111 108 102 Duero Tajo Júcar Tormes Duero Flamisell Tajo Guadalhorce Torina Ebro Bibey Sil Ebro Camba Miño Tajo Nog Ribagorzana Ribera de Huelva Tajo Duero Duero Tajo Miđo Esla Nalón Miđo Tajo – Tiétar Navia Júcar Sil Lladore-Tabascán Miđo Alagón Nog Ribagorzana Guadiana Pumping capacity (MW) Pure 435 Pure 635 Mixed 825 Pure 451 Pure 360 Pure 362 Mixed 316 Mixed 270 Pure 221 Pure 210 Mixed 126 Mixed 133 Mixed 111 Figure Location of Spain’s main hydroelectric power plants Evolution of Hydropower in Spain 315 Approximately 10 000 MW have a high seasonal regulation, of which 2500 MW are equipped with pumping There are around 2350 MW in important power systems but with scarce regulation, and around 1300 MW in developments at the base of a dam The rest of the hydroelectric facilities consist of small power plants, many of run of rivers Spain’s hydroelectric potential is estimated at around 162 000 GWh yr−1, of which a little over 64 000 GWh are technically usable Taking into account that average yearly power production is around 35 000 GWh yr−1, there is still technical margin available The economically viable potential is estimated at 37 000 GWh, in accordance with the most recent data, not including the pumping plants This means that Spain is close to the economically acceptable ceiling However, some clarifications must be made On the one hand, this ceiling is moveable, as it depends on the economic conditions not only of the jumps themselves but also, and especially, of the power production strategies at national level, which depend on the degree of dependence, on power vulnerability, on petrol and gas prices, or on the consideration of other types of plants’ environmental costs, among others On the other hand, power production is far from this level in the last few years, partly due to low rainfall Exploitation during these dry years may be increased by building new facilities or improving the existing ones 6.11.1.5 Producing Companies The large electric utilities that have hydroelectric power stations in Spain are Iberdrola, Endesa, Gas Natural SDG, Acciona, E.ON Espa, and HC Energía The last two concentrate their hydroelectric activity mainly in the north part of the peninsula, while the others distribute their facilities over greater areas of the national territory A high number of other small companies must be added to these large ones, including those that have mini power plants with less than 50 and 10 MW and that are subject to the special electric production system The Administration is also the owner of a high number of toe of dam schemes, most of these in dams intended for regulation for irrigation or integral regulation of rivers Iberdrola is the result of a merger in 1991 between Iberdrola and Hidroeléctrica Española and owns 9187 MW Iberduero had its origins in Hidroeléctrica Ibérica, founded in 1901, and in Saltos del Duero, founded in 1918 with the purpose of exploiting the great hydroelectric potential of the Duero System They were merged in 1944, soon after joined by Saltos del Sil, born to exploit the great hydroelectric site of the Sil river and its tributaries Hidroeléctrica Española was founded in 1907, with its origins also being some of the schemes and concessions of Hidroeléctrica Ibérica The main hydroelectric development of Hidroeléctica Española took place in the Júcar and Tajo basins Endesa, with a current installed hydroelectric power of 4511 MW, was created with public funding in 1944 with the purpose of helping the private sector in hydroelectric development In 1983 the Endesa group was created, with the acquisition of some electricity companies such as Enher or Gesa, among others, from the National Institute of Industry In the 1990s it acquired Electra del Viesgo, the historical Sevillana de Electricidad, Hidroeléctrica de Catala, and Fuerzas Eléctricas de Catala Unión Fenosa was the result of the merger between Unión Eléctrica and Fuerzas Eléctricas del Noroeste (FENOSA) in the year 1982 The first had its origins in 1889, with the creation of the Compía General Madrila de Electricidad, which after several groupings became Unión Eléctrica Madrila in 1912 The second was created in 1943 to exploit several hydroelectric schemes in Galicia, in the northeast of Spain Recently, Unión Fenosa has merged into Gas Natural as Gas Natural SDG has a hydroelectric power of 1860 MW Acciona acquired Energía Hidroeléctrica de Navarra and assets from Endesa, Saltos del Nansa among them, to achieve the 857 hydroelectric MW The presence of E.ON is more recent, as it dates back to 2007 through its renewable energies affiliate and to 2008 as a market unit and as E.ON España, with 668 MW This presence is due to the acquisition of assets from Ente Nazionale per L’Energia Elettrica (ENEL), who in turn had acquired the old Electra de Viesgo from Endesa, one of the Spain’s historical companies created in 1906 The historical Hidroeléctrica del Cantábrico has merged into the EDP group (Electricidade Portugal) in the last few years under the name HC Energía It has 433 MW of hydroelectric power 6.11.2 Evolution of Schemes and First Developments 6.11.2.1 Periods in the Evolution of Development The demand of electric energy has been increasing from the first days until today, with variable rates according to economic growth in general and the industrialization level in particular The relationship between the industrialization and electric energy demand has always been similar This demand has been met throughout the twentieth century with different types of power plants, among which hydroelectric power plants have had varied importance The distribution of generation to satisfy such demand between the different stations has depended on several factors, among which we must mention the hydroelectric potential and its level of exploitation, the cost of produced power and the environmental problems of the different power plants, or the strategic decisions to protect different sectors of the national economy, just to mention some of the main ones The political and economic situation was also important in Spain in certain periods as it conditions the availability of equipment and building technology, as we will see later on From a technical point of view, the main factors were those corresponding to the state of the art of the technologies available for those elements that affect hydroelectric developments: turbines, turbo pumps, or generators, as well as hydraulic engineering, dam engineering, and tunnel engineering, essential elements in Spain’s hydroelectric development 316 Hydropower Schemes Around the World (a) 1800 1600 Hydropower 1400 Thermal power Total installed power MW 1200 1000 800 600 400 200 1880 1890 1900 1910 1920 1930 (b) 4000 3500 Hydro 3000 Thermal MWh 2500 Total generation 2000 1500 1000 500 1880 1890 1900 1910 1920 1930 Figure (a) Installed power in Spain between 1880–1940 period (b) Generated power in Spain between 1880–1940 period All these factors have contributed to the variation of the development and the hydroelectric use systems and their importance in the electricity sector in Spain throughout the twentieth century, with clearly different characteristic periods The first period goes from the first steps of electrical energy in Spain to the civil war (1890–1940), characterized by an important increase of installed power and of produced energy, especially since 1910 After some years during which thermal power plants supplied most of the energy, with the new century it was the hydroelectric power plants that began to absorb most of the demand In 1940, the installed hydroelectric power was 78% of the total and the generated power was 93% (Figures 6(a) and 6(b)) The 1940–73 period is characterized by the importance of hydroelectric production, which represented more than half the total electric production From 1973, the increase of thermal production in classic and nuclear power plants made hydroelectric power stop being the main source, and has from then on lost relative importance in terms of energy (Figure 7) If we take other factors into account, we can clearly distinguish two different phases within this period One is from 1940 to the second half of the 1950s, characterized by the use of building equipment already used before the civil war, as a result of the autarchic politic and of Spanish isolation, which meant a certain continuation of previous productions The second period begins with the change of decade from the 1950s to the 1960s, during which the confluence of several factors allowed for the great development of hydroelectric power The great development of dam engineering, the development of reversible power units, and the cost reduction in the construction of all types of works – hydraulic, underground, mechanical, and so on – due to the availability of new equipment, are the reason for the quick evolution in the development schemes On the other hand, the more constructive and economic facility in underground works allowed for a greater flexibility in hydroelectric schemes, making it possible to build developments unthinkable just a few years before From then, the construction of underground power plants and reversible power plants were commonplace From the middle 1970s, the increase of installed power continued increasing, but less than the classic thermal or nuclear power plants, despite of which the produced power stagnated to previous levels, with the exception of very favorable years in hydrological Evolution of Hydropower in Spain (a) 317 80 70 Biomass 60 Mini hydro Wind 50 GW Cogeneration 40 Nuclear Gas turbines 30 Thermal Hydro 20 10 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 (b) 300 250 Biomass Mini hydro TWh 200 Wind Cogeneration 150 Nuclear Gas turbines 100 Thermal Hydro 50 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Figure (a) Installed power in Spain between 1940–2008 period (b) Generated power in Spain between 1940–2008 period terms From 1990, the increase of installed power has been very little mainly due to electric system regulation installations and power increases in already existing plants (Figures 7(a) and 7(b)) In the last decade of the past century, a construction process of small plants and the renovation of others that were not in use began In the origins of this process we find, on the one hand, the development of more and more reliable power units and the remote control and/or centralization of operations, with the corresponding reduction of maintenance and operation costs and, on the other hand, the inclusion from 1997 of these plants in the special electricity production system, whose purpose is the promotion of renewable energy In each one of these periods, hydroelectric power and hydroelectric developments have had clearly different characteristics 6.11.2.2 6.11.2.2.1 The 1890–1940 Period First steps of electricity in Spain The first reference to the practical application of electricity in Spain dates back to 1852, when the pharmacist Domenech lit up his premises in Barcelona with a method invented by him That same year lighting tests were carried out in several public spaces using galvanic cells From then on, and with a higher intensity in the 1870s, certain areas of some cities began to be lit up, generally using dynamos powered by steam engines The production of electrical energy in important quantities for that time began in the mid-1870s, using thermal power units powered by coal and low-quality gas The first electricity supply contract dates back to 1876, Sociedad Española de Electricidad was the first Spanish electricity company In 1878, several squares, streets, and important buildings in Madrid were lit up, and at the beginning of the next decade in cities such as Valencia and Bilbao Increasing demand in the last two decades of the nineteenth century resulted in several companies being established with the only purpose of supplying electricity, both for public and private use 318 Hydropower Schemes Around the World In the last few years of the nineteenth century and in the beginning of the twentieth century it was supplied as direct current, which forced the power plants to be located near the consumption centers, which in turn limited the building of hydroelectric schemes and favored the use of thermal power plants With the first use of alternating current in the last few years of the century and its great development in the first decade of the twentieth century, the limitations of the location of hydroelectric power plants disappeared, making the boom that took place during the second decade of the century for this type of energy possible In 1901 there were 861 electric power plants in Spain, with a total installed capacity of nearly 100 MW Around 65% of them were thermal and 35% were hydroelectric, 650 mostly dedicated to public services, and the rest for private use More than half of the total, around 510, produced in direct current and the rest in alternating current The uses of this energy were around 87 000 incandescent lamps and 1500 arch lamps for public lighting, and 240 000 incandescent lamps, 2800 arch lamps, and 2036 engines for private use 6.11.2.2.2 The electricity sector in the first decades of the twentieth century In the 1901–30 period, the total electric power was multiplied by 12, reaching 1200 MW, which became 1600 MW in 1936, a number that slightly dropped at the end of 1939 as a result of the civil war destructions, which paralyzed the development of the Spanish economy This big increase of installed power resulted in there being a small excess of installed production over consumption during this period Increase in demand was variable: 8% between 1901 and 1922, 10% up to 1930, and 5% up to 1936, very similar values to those of economic and industrial growth If in 1890 installed hydroelectric power in Spain was 30% of the total electric power, this percentage went up to 69% in 1910 and 77% in 1920 This percentage would become stable until 1936, the year the civil war paralyzed electric development As far as production is concerned, these percentages were even more favorable for hydroelectric power plants due to a higher amount of operation hours than those of thermal power plants So, in 1929, 81% of production was hydroelectric This percentage rose to 93% in 1936 (Figure 6) Apart from the general use of alternating current, the origins of this development lie in the fewer total costs of hydroelectric power despite a higher initial investment, this was not only due to the zero cost of water but also to the increase in the cost of coal, gas, and petroleum products throughout these first few decades The construction of hydroelectric schemes of considerable size was generalized from the last years of the century’s first decade to cope with the demand, which involved high economic investments This was only possible due to the creation of a large number of electricity companies intended for production and distribution, which was led by private initiatives and with important participa­ tion of the banking sector 6.11.2.2.3 Main hydropower developments Between 1901 and 1902, the first large (for that time) hydroelectric plants began operating, among which we must mention those of Molino de San Carlos, near Zaragoza, Navallar, on the Manzanares river, the first to supply this type of power to Madrid, and San Román, on the Duero river near Zamora The Navallar power plant, with 1750 CV installed in four power units was the first of series of facilities that supplied power to the capital city from the rivers located to the north of it (Figure 8) The source of the scheme was the first dam of Manzanares el Real, with a height of 10 m and which was raised in 1906 A canal flowed from the dam which, apart from feeding the plant’s surge chamber, served as a reservoir from which water was pumped to the city of Colmenar It was one of the first important dams destined for hydroelectric and multiuse purposes The San Román power plant, which had an installed capacity of 5000 CV and took advantage of a long meander of the Duero river, with a m-high dam and a 15 m head meant an important leap in terms of installed capacity, superior to those built until then Until 1910, a large number of similar schemes were built, most of them with installed capacities of 1500–2000 kW and located in medium river watercourses Most of them were characterized by their diversion schemes, with a weir, a canal which was not too long and flowing parallel to the river, a small surge chamber and one or more horizontal configuration power units with Francis turbines In 1909, the Salto de Molinar, on the Júcar river, was inaugurated It was the most remarkable hydropower project built in Spain until then The development has been historically considered as one of the best and most profitable in Spain It was projected for a production of 70 GWh, when Madrid’s consumption was 30 GWh Three 4500 kW power units were initially installed, in the following year an additional power unit was installed, achieving an installed capacity of 22 500 kW If the development was Figure Navallar power plant (1902) Cross-section and inside the power plant Evolution of Hydropower in Spain 327 Figure 24 La Cohilla dam during construction and Eume dam Figure 25 Mequinenza power plant and dam dams The diversion of the waters, with a very constant flow, is turbined to the Barázar power plant, of 83 MW, taking advantage of a 330 m height variation levels, resulting in an average power production of 170 GWh yr−1 In many of the rivers where dams and power plants were set up before the war, they continued building during this period by making use of the existing regulation and infrastructures 6.11.2.4 6.11.2.4.1 The 1960–75 Period The electricity sector The 1959 Stabilization Plan, which established a stable framework for growth, the First Development Plan of 1964 and the opening to the ‘outside world’, which favored incoming currencies and commercial exchange, was the source of the great Spanish economic development from 1960 The electricity sector was an active collaborator in this development, quickly adapting to the demand The previous existence of a fairly large and comprehensive supply network and its extension throughout these years was a decisive factor In these years they achieved to electrify practically the entire national territory The installed power rose from 6600 MW in 1960 to 18 000 MW in 1970 and to 25 500 in 1975, hence four times as much in 15 years Production also rose from 18 600 GWh in 1960 to 56 500 in 1970 and to 82 515 in 1975, five times as much in the same period of time During these years, hydroelectric power units were greatly developed, from 4600 MW installed to 12 000 However, the high increase was due to the building of new thermal plants, both conventional fuel oil plants in a context of low oil prices, and nuclear power plants, with the start up of José Cabreras in 1968, of 160 MW, Garoña in 1971, with 466 MW, and Vandellós I in 1972, with 500 MW (Figure 7) In 1973, the first oil crisis took place, which multiplied the source price by six, despite that the important fleet of thermal power plants under construction used this fuel Spain only reacted to this in 1975, when the National Energy Plan was passed, but effective measures were not taken to change the energy model, which was indeed done one decade later, in 1983, with the II National Energy Plan 328 Hydropower Schemes Around the World 6.11.2.4.2 The golden age of dam engineering in Spain Since the Roman times the construction of dams in Spain has been common, due to the semiarid nature of a good part of the territory and the temporal irregularity of precipitation and runoffs Since then, and throughout all the periods, dams have been essential in social and economic development Dam engineering has always been level with the world’s best with important and numerous constructions, even during unfavorable periods, as previously mentioned This important and continuous experience reached its climax from 1960 with the conjunction of all the mentioned factors, which favored the building of important dams with different purposes We can therefore affirm that the 1960s and 1970s were the golden age of dam engineering in Spain From all the dams of this golden age, those built for hydroelectric purposes stand out, most of them among the highest dams built in Spain (Table 3) This golden age of dam engineering was so especially in the construction of arch dams in general and double-curvature dams in particular, but also with a few important examples of buttress dams and embankment dams In the Duero System the arch-gravity dam of Aldeadávila, 140 m high, and the double-curvature dam of Almendra, 202 m high, were built in this period The first was finished in 1963 and is located in an impressive granite canyon formed by the Duero river A double-curvature dam was the first selection, but the high floods made them opt for the arch-gravity type It is one of the most beautiful Spanish dams, not only for the surroundings but also for the dam itself In 1970, the Almendra double-curvature dam was finished, the highest in Spain, which rises beyond the closed topography, thanks to two gravity abutments on which it is supported For the closure of the lateral troughs, a buttress dam and an embankment dam with a bituminous concrete face were built (see Section 6.11.3) In the Sil Sytem, the construction of the Santa Eulalia ended in 1967 It had the slimmest and most curved double-curvature dam ever built in Spain (Figure 26) Most of the building equipment that was later used to build the great Almendra dome was fine tuned here In the same system, the Las Portas double-curvature dam was finished in 1975, with a height of 141 m, which was the third highest hydroelectric dam (Figure 26) The Belesar dam, on the Miño river and 132 m high, and the Valdecañas dam, on the Tajo river, 78 m high with a singular arrangement, with the power station at the base of the dam, protected by a small arch cofferdam and with spillways in tunnels on both sides (Figure 27), were built in 1963 and 1964 Other double-curvature dams built during these years included La Jocica (1964), 87 m high and very narrow, and that of La Barca (1966), 74 m high, over the Cantabrian Narcea river The Susqueda dam (1968) was built over the Ter river, with a height of 135 m Among the buttress dams we must mention that of José María de Oriol (1969), associated to the Alcántara reservoir, with a height of 130 m and a double-buttress or ‘Marcello’ type, which was a world record for its height in this type of dam until the Itaipu dam was built This dam changed the single-buttress dam type used in profusion throughout the 1950s and 1960s by hydroelectric companies It was also the last important dam of this type built in Spain (Figure 28) Gravity dams continued to be the most used for lower heights, while embankment dams were used to a lesser extent, of which that of Portodemouros (1967), 91 m high, stands out Among the gated dams, we must mention those of Velle, Castrelo, and Frieira, all over the Miño river, with heights in the 25–35 m range and built in the 1960s Table Main hydroelectric dams in Spain Dam Height (m) Typology Year River Location Reservoir capacity (hm3) Almendra Canelles Portas, Las Aldeadavila Susqueda Belesar José María de Oriol Escales Salime Cohilla, LA Cortes II Matalavilla San Esteban Bao Eume Ricobayo Doiras Tanes Peares, Los Portodemouros 202 151 141 140 135 132 130 125 125 116 116 115 115 107 103 99 95 95 94 91 VA VA VA VA-PG VA VA CB PG PG VA VA-PG VA VA-PG PG VA PG PG PG PG ER 1970 1960 1974 1963 1968 1963 1969 1955 1956 1950 1988 1967 1955 1960 1960 1934 1934 1978 1955 1967 Tormes Noguera Ribagorzana Camba Duero Ter Miño Tajo Noguera Ribagorzana Navia Nansa Jucar Valseco Sil Bibey Eume Esla Navia Nalon Miño Ulla Salamanca Huesca Ourense Salamanca Gerona Lugo Caceres Huesca Oviedo Santander Valencia Leon Ourense Ourense Coruña, A Zamora Oviedo Oviedo Lugo Coruña, A 2.649 687 535 114 233 654 3.162 153 266 12 118 65 213 238 123 1.150 96 33 182 297 Evolution of Hydropower in Spain 329 Figure 26 Santa Eulalia and Las Portas dams, in the Sil System Figure 27 Valdecañas dam 6.11.2.4.3 Main hydropower developments From a technical point of view, the important hydroelectric development in this period was based on three cornerstones: the construction of large dams, the construction of underground power plants, and the development of pumping installations The first enabled the creation of higher heads and a higher regulation The second, due to the development and availability of building equipment and building techniques, enabled a higher flexibility in the arrangement of development schemes without the technical or environmental conditionings of surface locations The third enabled for the development of electric power storage schemes in the way of potential hydraulic power This was an important factor in an electricity system such as the Spanish one which was beginning to generate more through thermal plants The pumping installations of that time continued to be used for decades and are actually still in use, although with different criteria At present, and as explained further on, we need pure pumping facilities that allow us to supply very concentrated peaks and with a relatively low number of operative hours In the 1960s and 1970s pumping was understood as a storage means, by means of pressure diversions, in lateral basins of the main riverbeds, where the reservoir capacity and the flow availability did not coincide geographically With the change of generating model, this concept changed toward the pure pumping facilities in the 1980s with the purpose of serving as system regulation and to be able to supply the strong peaks This does not mean that both approaches are different, but complementary, when not coincidental The main pumping developments carried out in this period are connected to three of the main Spanish development schemes: the Duero System, the Sil System, and the Tajo Inferior Development The first development was carried out from the first decades of the twentieth century, and was continued during the 1940s and 1950s with classic schemes, while the second began its development 330 Hydropower Schemes Around the World Figure 28 JM de Oriol Dam after the war, as we have already pointed out But the definite boost during this period in both of these was, to a great extent, due to the application of pumping The third, that of the Tajo, was developed in a concentrated manner between 1960 and 1975, and had pumping as its main element from the start The Sil System takes advantage of the waters of the Sil river, as well as of most of its tributaries It currently has an installed power in generation of 1270 MW and in pumping of 400 MW, with 19 power plants, 45 power units, and 17 large dams, all built between 1952 and 1994 It has the highest concentration of hydroelectric developments in Spain (Figure 29) There are three pumping stations in the system: Camba-Conso, Bao-Puente Bibey, and Santiago-Jares The first (1975) is the main one, with an installed power of 230 MW, a flow of 120 m3 s−1 and a 230 m head between the power house and the large multiannual Las Portas reservoir, which confers a great power reserve for all the power plants located downstream, among which is that of Bao (1964), with one of the four pumping units with a ternary arrangement This station, along with that of Aldeadávila I, built at the same time, were the first step in the application of the modern underground excavation techniques applied in hydroelectric power plants and galleries in Spain (Figure 30) The analysis of the study phases of the Tajo Inferior Development is interesting, as it highlights the change in the design of hydroelectric systems that took place in only a few years Downstream from Toledo, the Hidroeléctrica Española concession allowed for the exploitation of the river itself, with a total height variation of 280 m (Figure 31) The top 40 m were exploited with a conventional power plant in accordance with the existing easements, fundamentally agricultural and for town use For the lower 240 m there were three solutions The first was a conventional scheme, with four development steps by means of dams and power plants at their base Subsequently, the inclusion of the exploitation of one of its tributaries, the Tiétar, was Figure 29 Current schematic plan and profile of the Sil System Evolution of Hydropower in Spain 331 Figure 30 Bao power plant Cross-section, in which the difference between the three generation units and the pumping-generation unit are shown Figure 31 Scheme of the Tajo project, situation in 1964 considered And finally, soon after the previous one, the possibility of including pumping was considered, which was indeed done in two of the power plants On the basis of the need to create a large regulation reservoir, it was situated as far upstream as possible, resulting in the Valdecañas dam In order to create a minimum head of 50 m, a volume of 270 hm3 was sacrificed, while the oscillation between a height of 50 and 75 m created a regulated water reserve of 1275 hm3, not excessive if we take into account that, although it is one of the main ones in Spain, it has annual irregularities of 1–6 and monthly of 1–140 As downstream the Tajo river did not receive important contributions, the construction of more regulation reservoirs was not considered, using the following step, of 46 m, with a second dam, that of Torrejón, with a power plant at the toe of the dam This scheme was considered as satisfactory until the mid-1950s, with two power plants, one of 225 MW in Valdecañas and the other of 130 MW in Torrejón, plus another two to be exploited later on The expected productivity of this scheme in the first two power plants was 550 GWh in the first and 345 GWh in the second, that is, a total of 895 GWh, but with strong oscillations, from to in annual values 332 Hydropower Schemes Around the World On the other hand, a group of power plants at the base of dams fed by an important regulating reservoir such as that of Valdecañas was considered as ideal to supply the connection load peaks In this way, first the partial exploitation of the Tiétar river’s resources was considered, being a tributary of the Tajo downstream from the projected Torrejón jump, and second the large-scale adoption of pumping with reversible power units in both sites The final result was the construction of the Valdecañas power plant, at the toe of the dam, with a power of 250 MW and pumping from the lower reservoir, that of Torrejón The incorporation of the Tiétar to the scheme immediately presented the convenience of also using its contribution, for which the possible pumping from it to the Tajo in the Torrejón reservoir was considered For this purpose a power house was built to serve both reservoirs, that of Torrejón and a new one on the Tiétar, in an area in which they are both very close to each other, upstream from their confluence Both reservoirs have a difference in height of 20 m This power plant was designed to have a great operational flexibility between both rivers, in such a way that Tajo-Tajo and Tiétar-Tajo turbination is possible, as well as Tajo-Tajo, Tiétar-Tajo, and Tajo-Tiétar pumping In this way, the expected productivity was 710 and 420 GWh, respectively, with a total of 1130 GWh, with a minimum improvement of 26% and only a 1–2 variation (Figure 32) The scheme continued with the construction of the José M de Oriol power plant, which was initially expected for a power of 600 MW and finally achieved 935 MW, being Spain’s second largest today The last phase of the development was the construction of the Cedillo power plant, located at the point where the Tajo enters Portuguese territory, in the confluence of the Tajo and Sever rivers The power house is located in the dam with the same name, between two large spillways, one per river Its installed power is 500 MW (Figure 33) Figure 32 José M de Oriol power plant Tiétar-Tajo pump operation Figure 33 Cedillo power plant and dam Evolution of Hydropower in Spain 333 Many other developments were built over this period of strong hydroelectric expansion The schemes used in most of them were those with power plants at the toe of dams and those with diversion schemes, both in areas with strong height variations such as in the century’s first decades, and in lesser height variations and more important flows in more regulated river sections 6.11.2.5 6.11.2.5.1 The Last Three Decades The electricity sector At the end of the 1970s and beginning of the 1980s, several coal (both national and imported) power plants began to operate In addition, the nuclear program continued and between 1983 and 1988 seven power plants began operating, with a total installed power of more than 7000 MW The quick fuel plant replacement process and the development of the nuclear program had a double effect on the electricity sector: The strong indebtedness of the electricity companies and the overcapacity made it necessary for a Legal and Stable Framework to be established in 1988, which stabilized the sector and in the 1990s enabled the electricity companies to reorganize, mainly in two large groups: Endesa and Iberdrola, which also began to expand internationally In 1995, the Law for the Regulation of the National Electricity System was enacted, and in 1996, the EU Council passed the Directive concerning common rules for the internal market in electricity As a result, in 1997 the Electricity Sector Law was enacted, introducing the most important regulatory changes in this sector’s history, in the line of a liberalization of the electricity market and of the separation of the generation, transport, distribution, and marketing activities Subsequently, the figures of the Market Operator, whose purpose was the market’s economic management, and that of the System Operator, whose purposes were to the system’s technical management and the management of the transport network, were created At the beginning of this century, the Spanish electricity sector was characterized by a low reserve of installed power, as a transport network with congestion problems in certain areas, and an important increase in demand, a result of the strong economic growth All this was the cause for an important development in the construction of new power plants: on the one hand, combined cycle plants, and on the other hand, renewable energy plants in general and wind farms in particular, under the shelter of favorable laws for this type of energy and of the social concern in the ambit of environmental protection 6.11.2.5.2 Main hydropower developments From 1985 the economically exploitable hydroelectric potential was practically used, so from then on the developments have been of four types Among the medium and great power developments, the pumping plants stands out, especially pure pumping plants, and those built as an extension of relatively important power plants, under the shelter of the gradually greater regulation upstream with reservoirs of all uses throughout time Two types stand out among the small power developments: small power plants built under the special production system and those that exploit the existing regulation hydraulic installations, such as the irrigation or supply regulation dams Among the pure pumped storage we must mention those of Aguayo, with an installed power of 362 MW; Estangento-Sallente, with 450 MW; Guillena, with 210 MW; La Muela, with 635 MW; Moralets, with 222 MW; and Tajo de la Encantada, with 360 MW; 2240 MW in total, built in these last few decades, to which we must add the 112 MW from the Gabriel y Galán and the 126 MW of the Tanes mixed pumped storages To complete the pumping power plant overview in Spain, we would have to add the over 2600 MW of installed power of mixed pumping plants built before 1975, in the aforementioned Saltos del Sil, Tajo System, Duero System, and others with less power Total power installed in reversible power units is, in terms of turbination power, of the order of 5100 MW This capacity will be increased in the coming years with the installations being built and those being projected The first pure pumping plant built in Spain was that of Guillena, in the Guadalquivir basin near the city of Seville in 1970 Between 1983 and 1984, the reversible power plant of Aguayo became operative in the Cantabrian mountain range, whose lower reservoir was formed by raising the existing Alsa dam (Figure 34) This reservoir is also part of the Ebro-Besaya interbasin diversion Between 1986 and 1989, the Moralets pumping plant was built at the headwaters of the Noguera Ribagorzana river The location of the Tajo de la Encantada pure pumping plant is rather singular, with the building inside the reservoir (Figure 35) The pure pumped storage of Estangento-Sallente, Spain’s second largest in terms of power, is located at the highest watercourse of the Capdella river, and uses as its upper water tank the lake which was raised with the Estangento dam, which has been mentioned previously (Figure 11) The initial dam has the same purpose as that of the beginning of the twentieth century, which is to collect the waters for the power station, while the rise is used to regulate the pumping The lower tank was formed by building a 90 m-high embankment dam (Figure 36) The most important pure pumped-storage plant in Spain is that of La Muela, located near the Cofrentes Nuclear plant, on the Júcar river This pumping plant is currently being enlarged, which will make it Spain’s most powerful plant (Figure 37) The schemes of the two mixed power plants built in this period are interesting That of Tanes is part of the supply system to the central region of Asturias and is located between two reservoirs, Tanes and Rioseco, and has the particularity that the power plant is located near the middle point of the hydraulic circuit The Gabriel y Galán mixed pumping plant is part of a development built in the 1980s and of which the Guijo de Granadilla dam is also part Both the power plant and the dam are located between two dams built in the 1960s for irrigation purposes; the upper dam, Gabriel y Galán, is a regulation dam, and the lower dam, Valdeobispo, acts 334 Hydropower Schemes Around the World Figure 34 Alsa dam and Aguayo reversible power plant Figure 35 Llauset dam and diagram of the Moralets jump Figure 36 Tajo de la Encantada reversible pumping plant: Diagram and plant Evolution of Hydropower in Spain 335 Figure 37 Aerial view of La Muela pumping plant as a diversion dam In between there is a height variation that was taken advantage of by building the Guijo de Granadilla dam, which enabled the overlapping of the three reservoirs and allowed for the installation of two pumping plants, the aforementioned Gabriel y Galán, of 112 MW, and that of the intermediate plant, of 54 MW (Figure 38) The Canal de Isabel II Hydroelectric Power Plant System is an example of one of the developments with less installed power in existing hydraulic installations It is a public entity that has supplied water to Madrid since 1850 The entity took advantage of the regulation dams and pipes, and in the first phase in the 1990s seven new power units were installed and some of the existing units were modernized With regards to the small hydro, some have been built from scratch and others by using old power plants built in the first years of the nineteenth century and which were abandoned in the second half of that century due to their scarce profitability and competition from large power plants of all types and sizes The promotion of renewable energy over the last decades, the existence of usable infrastructure, and the general use of automation and remote control have made them be profitable once again (Figure 39) Figure 38 Scheme of the Alagón river hydroproject Gabriel y Galán and Guijo de Granadilla dams and power plants 336 Hydropower Schemes Around the World Figure 39 Canal of the Tranco del Diablo small hydro 6.11.3 A Representative Case: The Duero System and Its Evolution The hydroelectric production Duero System is exploited by Iberdrola, the heir and continuation of the companies that studied and built the scheme projects from the first years of the twentieth century, first Saltos del Duero and then Iberduero It is the most comprehensive and most complex hydroelectric system with the most installed power in Spain In addition, it has the first and third largest individual facilities in terms of power (Aldeadávila and Villarino), the highest dam (Almendra), and one of the most beautiful (Aldeadávila), among other important ones (Figure 40) The Duero river, after crossing the large sedimentary basin with rather gentle height variations, narrows in the Arribes del Duero granitic massif, where the height variations between the top peneplain and the riverbed can exceed 400 m in some points In the section where this narrowing takes place, it has three sections from the administrative point of view: a top section in Spanish territory, a second section on the Portuguese border exploited by Portugal, and a third section also on the border and exploited by Spain All of this was a result of an agreement reached between both countries in 1927 Spain’s main jumps are located on the Duero itself, on the two previously mentioned sections, and on its tributaries: the Esla, which at its confluence nearly has as much flow rate as the main river and the Tormes, which joins with it in the separation between the two international sections, where the Spanish one begins We also have to add those of the Tera river, a tributary of the Esla (Figure 41 and Table 4) The general scheme of the Duero, Esla, and Tormes development was already planned in the second decade of the twentieth century It consisted of a large regulation reservoir in the Esla river, as it could not be built on the Duero, which is the headwaters of the entire system Downstream, in the Spanish Duero, these regulated flow rates are exploited in the Villalcampo and Castro power plants, built in the 1940s and beginning of the 1950s Further downstream, on the International Duero exploited by Portugal, we find the Portuguese Miranda, Picote, and Bemposta power plants The Tormes river discharges its waters at the end of this section Figure 40 Almendra and Aldeadávila dams Evolution of Hydropower in Spain 337 Figure 41 Plan and current scheme of the Duero System Table Duero System power plants: Main characteristics Power plant Subsystem Tera Cernadilla Valparaiso Santa María Agavanzal Esla river Ricobayo I Ricobayo II Duero national San Román Villalcampo I Villalcampo II Castro I Castro II Duero International Aldeadávila I Aldeadávila II Saucelle I Saucelle II Tormes Villarino Total Dam type/height MW Head Flow Number of units Pumped-storage type Production PG – 69 PG – 67 PG – 43 30 62 23 56 48 36 60 160 72 82 75 64 PG – 100 133 135 83 83 240 210 638 46 + 264 Sist PG – PG – 52 96 110 80 110 15 37 37 42 42 43 303 340 270 340 35 744 718 420 240 250 138 138 63 63 617 350 468 480 810 3223 402 232 39 PG – 53 AG – 140 PG – 83 BV – 202 755 3807 Mixto 1302 321 Mixto 1376 They are exploited downstream by the Aldeadávila I and II power plants and subsequently by those of Saucelle On the other hand, the waters of this last reservoir can be pumped to the Aldeadávila reservoir and from it to the great Almendra reservoir built on the Tormes (Figure 41) From the 1970s, the Tera development was initiated, a tributary of the Esla, with the construction of the three new dams: Cernadilla, Valparaíso, and Santa María de Agavanzal, and their corresponding power plants at their base, which in turn increased the regulation of the system downstream This fact, together with the regulation increase at the headwaters of the Esla by means of dams for irrigation purposes, enabled the construction of the new previously mentioned Ricobayo II power plant From the first studies that date back to the first decade of the nineteenth century and the first execution, the Ricobayo dam (1932), until the last execution, the construction of the Ricobayo II power plant (1998), nearly one century has elapsed, during which the social, economic, technical, and technological conditions have been changing This meant that the projects and constructions were addressed differently, with different schemes and different dams and power stations And all of this without changing the general exploitation scheme proposed by José Orbegozo 338 Hydropower Schemes Around the World The first period goes from 1902, the date of the first concession in the International Duero, to 1927, date in which the joint exploitation with Portugal was signed From a technical point of view, the first developed schemes were successive diversion channel schemes over the international Duero, with canals on the Spanish side seeing the problems posed by Portugal to reach an agreement (Figure 42) In 1924, seeing the proximity of the agreement being signed, Orbegozo presented the project in an almost definite manner On the Spanish side, a regulation dam on the Esla, the current Ricobayo, and a dam on the national Duero, that of Villardiegua, took advantage of the entire section of the current Villalcampo and Castro reservoirs The first section of the international Duero, and awaiting the treaty, it was solved based on a diversion waters by means of a canal that led to a power house, also on the Spanish margin, located just before the confluence of the Tormes The second section of the International Duero exploited that of Aldeadávila by means of a dam and another diversion scheme, that of Saucelle (Figure 43) On the Tormes, exploitation was to be by means of two dams and their corresponding power houses and a diversion scheme with the corresponding power house, between them This ‘visionary’ solution was the one that was developed later on, in accordance with the logical technical advances Thus, in the second period, from 1927 to 1936, the Ricobayo dam was built, with a height of 100 m instead of the 70 initially conceived, as a result of the greater experience in dam building The location did not change at all It was the highest in Spain at that time and one of the most important in Europe (Figure 44) The third phase took place during the 1940–60 period, in which due to the circumstances, the construction of only one dam on the Spanish Duero was discarded and two smaller dams were built: those of Villalcampo and Castro and the development of the Saucelle project, built as a dam and not as a diversion scheme (Figure 45) The fourth phase is that of the development of the Aldeadávila and Almendra-Villarino dams and power plants, more technically advanced installations than the previous ones, which included underground power plants and mixed pumped storages The Villarino power plant, with a large 202 m-high dam, replaced the previous three Tormes steeps, something unthinkable 50 years Figure 42 Ugarte Solution (1919) Figure 43 1924 Orbegozo Solution Evolution of Hydropower in Spain 339 Figure 44 Ricobayo dam Figure 45 Castro and Saucelle dams before Modern underground excavation techniques were used for the first time in the Aldeadávila I power plant Technical advance allowed to substantially improve the installed power and system’s total power with the same initial concept (Figures 46 and 47) In the fifth phase, from 1975 to today, executions have taken two directions: the exploitation of the Tera by means of the aforementioned power plants and the power increase of the existing power plants, those of Villalcampo and Castro in 1977, Saucelle II in 1989, and Ricobayo in 1988, by building new power units in all of them 6.11.4 The Future of Hydroelectric Power in Spain The need of new hydroelectric power in the Spanish Electricity System is mainly determined by three factors First, the increase in demand of electricity, which was 27% in the 2001–07 period, a big necessary investment in new power generation plants Environmental conditions and technological advances have made the technologies developed throughout this decade to be renewable energy, especially wind energy, and combined cycles These conditions make the investments in new hydroelectric equipment along with other renewable energy having to decisively contribute by achieving the long-term objectives of greenhouse gas emissions Second, the increase in peak demand, which in the same previous period was nearly 29%, rising from 35 000 to 45 000 MW and which is expected to be nearly 59 000 MW in the year 2016 In order to cover this demand, there needs to be fast-response technologies that operate few hours per year Hydraulic power plants with high regulation can fulfill this mission 340 Hydropower Schemes Around the World Figure 46 Villarino power plant: Diagram Figure 47 Aldeadávila power plant: Diagram Evolution of Hydropower in Spain 341 And third, the uncertainty and volatility of wind power production In Spain, the current wind power is 17 000 MW, which is expected to increase to 29 000 by 2016, 25% of the total Great variations are already taking place in produced wind power Thus, in November 2008, in two days wind power went from covering 43% of the demand to only 1.2% In this way, couplings to the network can go from 1000 to 6000 MW in h or to 11 000 MW in 24 h This volatility of wind power requires the system to have quick-start or quick-stop high power technologies that replace it Pure pumping hydropower plants and those with regulation reservoirs play a vital role to fulfill this mission As an example, and with these purposes, Iberdrola expects to increase power by nearly 2000 MW between pure pumping plants and the increase of power in existing power plants: La Muela II Pure pumping with 850 MW of turbination power It is the second part of the current La Muela I pumping plant, with a power of 630 MW If to these we add the power plant at the base of the Cortes II dam, with 280 MW, the complex will achieve 1760 MW of installed power, the largest in Spain Santa Cristina Pure pumping with 750 MW of turbination power Located in the San Esteban reservoir San Esteban II Underground power plant with 175 MW that will be added to the current 264 MW San Pedro II New 25 MW power plant designed parallel to the current one In the case of the Canary Islands, the problem gets worse due to the higher rigidness of the electricity production by thermal power units, the development of wind power, and the nonexistence of hydroelectric power plants In order to minimize this problem, projects are being implemented These are small projects but important ones due to the problems they solve Among these we must mention the Soria pumping plant, located on the island of Gran Canaria, which will use the existing reservoir of the same name, created by a 130 m-high double-curvature dam, and which will have an installed turbination power of 150 MW, of which 50 MW will only come from turbination and 100 MW from pure pumped storage References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Buil Sanz JM and García AG (2006) Hydropower Dams in Spain Madrid, Spain: Colegio de Ingenieros de Caminos, Canales y Puertos y SPANCOLD Perán F and Pérez JJ (2009) Pumped storage to support wind HRW 17(3) Iberdrola (2006) Large Dams Salamanca, Spain: Iberdrola García AG and Buil Sanz JM (2006) The role of hydro and future pumped-storage plans in Spain International Hydropower and Dams Villalba J (2000) The value of water for energy generation Water Economics Conference, Valencia, Spain Marcos Fano JM (2004) History and current overview of the Spanish electrical system Energía y Sociedad (Physics and Society) Magazine Number 13, Madrid, Spain Bueno Hernández F History of Electrical Energy in Spain Díez-Cascón Sagrado J and Bueno Hernández F (2000) Dams Engineering: Concrete Dams Universidad de Cantabria, Santander Endesa Worldwide (2006) Large Dams Endesa, Madrid Unesa (2004) The Electricity Sector through Unesa 1944–2004 Unesta, Madrid ... 6. 095 5.845 1.922 228 2.819 359 62 6 2.095 11. 012 791 31 16 49 54 47 23 35 26 83 76 64 46 12.250 4 26 688 1.223 18 110 .1 16 7.219 56. 063 39.175 41 Figure Spanish hydrographic basins Evolution of. .. Lugo Coruña, A 2 .64 9 68 7 535 114 233 65 4 3. 162 153 266 12 118 65 213 238 123 1.150 96 33 182 297 Evolution of Hydropower in Spain 329 Figure 26 Santa Eulalia and Las Portas dams, in the Sil System... 62 23 56 48 36 60 160 72 82 75 64 PG – 100 133 135 83 83 240 210 63 8 46 + 264 Sist PG – PG – 52 96 110 80 110 15 37 37 42 42 43 303 340 270 340 35 744 718 420 240 250 138 138 63 63 61 7 350 468