Volume 6 hydro power 6 01 – hydro power – introduction

Volume 6 hydro power 6 01 – hydro power – introduction Volume 6 hydro power 6 01 – hydro power – introduction Volume 6 hydro power 6 01 – hydro power – introduction Volume 6 hydro power 6 01 – hydro power – introduction Volume 6 hydro power 6 01 – hydro power – introduction

6.01 Hydro Power – Introduction A Lejeune, University of Liège, Liège, Belgium © 2012 Elsevier Ltd All rights reserved 6.01.1 6.01.2 6.01.2.1 6.01.2.1.1 6.01.2.1.2 6.01.2.1.3 6.01.2.1.4 6.01.2.1.5 6.01.2.2 6.01.2.2.1 6.01.2.2.2 6.01.2.2.3 6.01.2.2.4 6.01.2.2.5 6.01.3 6.01.3.1 References Introduction Hydroelectricity Progress and Development Key Features of Hydroelectric Power Cost Ancillary services Pumped-storage plants GHG emissions Environmental and social problems Hydropower Development Where the hydropower potential has been exploited Where large hydropower potential has still to be exploited Hydropower in integrated water resources management International cooperation Guidelines Volume Presentation Contributions and Authors, Affiliations of Volume Glossary Baseload power plant Baseload plant (also baseload power plant or base load power station), is an energy plant devoted to the production of baseload supply Baseload plants are the production facilities used to meet some or all of a given region’s continuous energy demand, and produce energy at a constant rate Energy Energy is the power multiplied by the time Gigawatt hour (GWh) Unit of electrical energy equal to one billion (109) watt hours Hydropower Hydropower, P = hrgk, where P is Power in kilowatts, h is height in meters, r is flow rate in cubic meters per second, g is acceleration due to gravity of 9.8 ms−2, and k is a coefficient of efficiency ranging from to Hydropower resource Hydropower resource can be measured according to the amount of available power, or energy per unit time 6 9 10 11 12 12 12 12 14 14 Megawatt (MW) Unit of Electrical power equal to one million (106) watt Pumped storage plant Pumped-storage hydroelectricity is a type of hydroelectric power generation used by some power plants for load balancing The method stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation Low-cost off-peak electric power is used to run the pumps During periods of high electrical demand, the stored water is released through turbines Although the losses of the pumping process makes the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest Pumped storage is the largest-capacity form of grid energy storage now available Tetrawatt hour (TWh) Unit of electrical energy equal to one thousand billion (1012) watt hours 6.01.1 Introduction In 2006, 17% of the world’s electricity that was generated from hydropower represented nearly 90% of renewable electricity generation worldwide Thus, it is by far the most widespread form of renewable energy Since 1965, the world’s total energy consumption from oil, natural gas, coal, nuclear power, and hydropower (of which only hydropower is considered as a renewable resource) increased from 46.52 to 127.93 million gigawatt-hours (GWh) A gigawatt-hour is a measure of the total energy used over a period, equal to million kilowatt-hours; GWh is sufficient to power approximately 89 US homes for year or 198 homes in the European Union for year As of 2007, the world’s primary energy consumption was for oil, followed by coal (at 35.6% and 2\8.6%, respectively), and consumption in those areas has been growing However, their growth has been curbed by the growth in energy consumption from renewable sources, including hydropower (Figure 1) Due to the growing demand, the use of energy is continuously increasing While in the 1970–2000 period the rate of increase was almost constant, in the past few years this rate increased Electricity is growing faster than any other end-use source Comprehensive Renewable Energy, Volume doi:10.1016/B978-0-08-087872-0.00601-6 Hydro Power 60 000 Natural gas Oil Coal Nuclear Hydro 50 000 TWh 40 000 30 000 20 000 10 000 1965 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 Figure Historical trend in world’s primary energy consumption by source, 1965–2006 (1 TWh = terawatt-hour = 1000 GWh) Source: BP (2009) [9] 20 000 18 000 16 000 Africa Middle East Asia 14 000 12 000 Latin America 10 000 CIS 8000 Japan and Pacific 6000 North America 4000 2000 1971 Europe 1975 1979 1983 1987 1991 1995 1999 2003 2007 Figure Electricity production (TWh) since 1970 of energy; the rate of increase is currently in the order of 800 terawatt-hour (TWh) yr−1 (more than +4% yr−1), as shown in Figure [1] This is related to the high rate of economic growth in emerging economies that mainly contribute to keep up energy needs and soaring prices While in Organisation for Economic Co-operation and Development (OECD) countries, accounting for half of the total electricity market, the power production continued with the usual historical trend (+2%), Asia and Middle East reported a rapid growth in their energy needs, with a special focus on the Chinese performance Asian power generation has now exceeded the amount of electricity produced by North America or Europe, and China now accounts for >16% of the world’s total electricity output The current distribution of electricity generation by region is shown in Figure [2] Electricity generation from coal and gas has been increasing faster than from any other sources, and counts now for >60% of total generation The future scenarios for energy have been examined by several agencies The latest scenarios about the global energy forecast from 2005–20 are the following: • World energy consumption will increase by about 30%, with China and India being the two main drivers • The power sector will be the biggest contributor to the world’s energy demand growth, representing about 40% of the total energy consumption increase by 2020 • The world’s CO2 emissions will increase up to 30% by 2020, mainly from Asia accounting for >70% of the total increase Based on existing and near-commercial technologies, the International Energy Agency [3] examined long-term scenarios and identified two such scenarios: • ‘Reference Scenario’ in which renewables will only constitute ∼14% of the world’s primary energy demand by 2030 Hydro Power – Introduction Rest of the World Latin 13% America 6% USA 22% CIS 7% EU-27 17% China 16% Asia+Pac (exc China) 19% Figure Electricity generation by region 2007 Oil 2015 Biomass 2030 Other renewables Nuclear Hydro Gas Coal 000 000 12 000 16 000 TWh Figure Evolution of global electricity production by fuel, 2007, 2015, and 2030 [3] Forecasts of International Energy Agency on nuclear power generation will be modified due to the Fukushima accident • ‘Alternative Policy Scenario’ in which renewables share rises to ∼16%, assuming the implementation of policies currently being considered by governments to ensure energy security and reduced CO2 emissions (Figure 4) In addition to the data illustrated in Figure 4, it is also necessary to consider the Millennium Development Goals (MDGs) [4] that 189 United Nations (UN) member states and at least 23 international organizations have agreed to achieve by 2015 The following eight development goals have been adopted to improve the social and economic conditions in the world’s poorest countries, encompassing universally accepted human values and rights: Eradicate extreme poverty and hunger Achieve universal primary education Promote gender equality and empower women Reduce child mortality Improve maternal health Combat HIV/AIDS, malaria, and other diseases Ensure environmental stability Develop a global partnership for development Though energy access is not an MDG in itself, it is evident that adequate provision of energy and energy access to all remain crucial for achieving the MDGs Furthermore, as stated in the 2010 ‘Millennium Goals Report’, severing the link between energy use and greenhouse gas (GHG) emissions will require more efficient technologies for the supply and use of energy and a transition to cleaner and renewable energy sources Therefore, it is evident that the world needs energy, clean energy, and cheap energy 4 Hydro Power 6.01.2 Hydroelectricity Progress and Development With two-thirds of the world’s electricity still coming from fossil fuel, hydropower currently produces the bulk (about 90%) of electricity derived from renewable sources The evolution of the world’s hydroelectricity production (TWh) since 1970 and its distribution by region are shown in Figures and [1] In about 60 countries, hydroelectricity is contributing >50% of the national electricity supply In absolute terms, more than half of the total hydroelectricity production is produced by five countries only: China, Canada, Brazil, United States, and Russia (Figure 7) [5] According to the World Register of Dams, dams were built around the world primarily for irrigation purpose (38%) and secondarily for hydropower purpose (18%) But today, some 8200 large dams are currently in operation having hydropower as the main or sole purpose Some of them serve very large hydro plants The largest hydroelectric dams and plants in operation are listed in Table About 900 GWh are currently installed and over 150 are under construction, most of them in Asia The largest and main schemes under construction are listed in Table The data greatly emphasize that the major role in hydropower dams construction is played by China and most of the largest hydroelectric dams under construction are constructed by the Chinese 3500 3000 2500 Middle East 2000 Africa Asia Latin America CIS Japan and Pacific 1500 1000 North America 500 Europe 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 Figure Evolution of hydroelectricity production (TWh) since 1970 2000 1800 1600 1600 1400 1400 India 1200 1200 China Japan 1000 1000 Canada 800 Venezuela United 800 Brazil Turkey Norway 600 Ukraine 600 Sweden Russia 400 Italy 400 Former URSS France 200 Spain 200 Other CIS Germany 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 OECD 1971 Figure Evolution of hydroelectricity (TWh) in OECD and non-OECD countries 1979 1987 1995 2003 2007 Non OECD Hydro Power – Introduction Producers TWh % of world total Installed capacity GWh % of hydro in total domestic electricity generation Peoples Rep of China 436 14.0 Canada 356 11.3 Brazil 349 11.2 Peoples Rep of China United States 318 10.2 United States 99 Russia 175 5.6 Brazil 71 Norway 98.5 Norway 120 3.8 Canada 72 Brazil 83.2 India 114 3.6 Japan 47 Venezuela 72.0 Canada 58.0 (based on production) Country (based on first 10 producers) 118 Japan 96 3.1 Russia 46 Venezuela 79 2.5 India 32 Sweden 43.1 Sweden 62 2.0 Norway 28 Russia 17.6 Rest of the world 1016 32.7 France 25 India 15.3 100.0 21 15.2 3121 Italy Peoples Rep of China World Rest of the world 308 2006 data World Japan 8.7 United States 7.4 867 2005 data Sources: United Nations, IEA Rest of the world* 14.3 World 16.4 2006 data Figure Hydroelectricity production by region Table Largest hydroelectric dams and plants in operation Capacity (MW) Max annual production (TWh) 17 600 a 14 000 10 200 370 809 400 > 100 90 46 21 22.6 26.8 20.4 Dam Country Year of completion Three Gorges Itaipú Guri (Simón Bolίvar) Tucuruί Grand Coulee SayanoShushenskaya Krasnoyarskaya Robert-Bourassa Churchill Falls Bratskaya Ust-llim skaya Yaciretá China Brazil/Paraguay Venezuela Brazil USA Russia 2009 1984–2003 1986 1984 1942/1980 1985/1989 Russia Canada Canada Russia Russia Argentina/ Paraguay China Pakistan China Brazil Brazil China Tajikistan 1972 1981 1971 1967 1980 1998 000 616 429 500 320 050 2009 1976 1999 1974 1994/1997 1988 1979/1988 500 b 478 300 200 162 115 000 Longtan Tarbela Ertan llha Solteira Xingó Gezhouba Nurek a b 22 500 when complete 6300 when complete 35 22.6 21.7 19.2 18.7 13 17.0 17.0 11.2 Hydro Power Table 6.01.2.1 Main schemes under construction Dam Country Maximum capacity (MW) Construction start Scheduled completion Xiluodu Xiangjiaba Longtan Nuozhadu Jinping-II Hydropower Laxiwa Xiaowan Jinping-I Hydropower Pubugou Goupitan Boguchan China China China China China 12 600 400 300 800 800 2005 2006 2001 2006 2007 2015 2015 2009 2017 2014 China China China China China Russia 200 200 600 300 000 000 2006 2002 2005 2004 2003 1980 2010 2012 2014 2010 2011 2012 Key Features of Hydroelectric Power After more than a century of experience, the strengths and weaknesses of hydropower are equally well understood Its weaknesses (possible negative environmental and social impact, high upfront investment, etc.) are often over­ emphasized by opponents to dams and reservoirs, whereas its numerous and great benefits are not always adequately emphasized An analysis of the advantages and disadvantages of hydropower is found in Chapter 3, Constraints of hydropower development (Hydropower: a multi benefit solution for renewable energy), from which are derived the comments given hereunder about the key features of hydropower 6.01.2.1.1 Cost There are six different sources of renewable electricity Hydroelectricity is the principle source with an 86.3% share of the total renewable output Biomass, which includes solid biomass, liquid biomass, biogas, and renewable household waste, is the secondary source with 5.9%, a little ahead of the wind power sector with 5.7%, followed by geothermal power with 1.7%, solar power including electro-solar and photovoltaic plants and ocean energies with 0.01% (Table 3) The cost of producing electricity is one fundamental criterion for decision making The high realization costs of dams, reservoirs, and hydro plants are sometimes considered to classify hydropower as an ‘expensive option’ However, hydropower converts energy from natural moving water directly into electricity and has therefore a very short and efficient energy chain, compared with fossil fuels It has also a very efficient conversion process: modern plants can convert >95% of moving water’s energy into electricity, whereas the best fossil fuel plants are about 60% efficient Hydropower also has the best performance with respect to energy payback ratio, which is defined as the ratio of energy produced during a plant’s life span to the energy required to build, maintain, and fuel the generating equipment A hydropower plant can produce during its life span >200 times the energy needed to build, maintain, and operate it (Figure 8) [6] Compared with the other renewable energies, hydropower is one of the least expensive sources of renewable electricity (Figure 8) [6] Furthermore, hydro’s autonomy from the fuel price variations, in addition to low annual operating costs, contributes significantly to ‘energy security’ (defined as “uninterrupted physical availability of energy products on the market, at a price which is affordable for all consumers,” Table 4) 6.01.2.1.2 Ancillary services Most of the hydropower projects were (and are) built to provide a primary ‘base load’ power generation Moreover, this pattern will continue in countries where hydropower occupies a significant share in the power generation mix As other technologies are introduced, hydro production is mainly used to respond to gaps between supply and demand, allowing the optimization of base load generation from less flexible sources (such as nuclear, thermal, and geothermal plants), which can continue to operate at constant level at their best efficiency The fast response of hydro plants enables to meet sudden fluctuations due to peak demand or loss of other power supply options These benefits are part of a large family of benefits of hydropower in assisting the stability of electricity production (ancillary services): • Spinning reserve: ability to run at a zero load while synchronized to the electric system; when loads increase, additional power can be loaded rapidly into the system to meet the demand • Nonspinning reserve: ability to enter load into the system from a source not on line; other energy sources can also provide nonspinning reserve, but hydropower’s quick start capability is unparalleled Hydro Power – Introduction Table Structures of electricity production from renewable sources in 2008 Source TWh % Hydropower Biomass Wind power Geothermal Solar including photovoltaic Marine energies 3247.30 223.50 215.70 63.40 12.10 0.54 86.31 5.94 5.73 1.69 0.32 0.01 Total 3762.54 100.00 Solar including photovoltaic, 0.32% Geothermal, 1.69% Wind power, 5.73% Marine energies, 0.01% Biomass, 5.94% Hydropower, 86.31% • Regulation and frequency response: ability to meet moment-to-moment fluctuations in system requirements; when a system is unable to respond properly to load changes, its frequency changes, resulting not just in a loss of power but potential damage to electrical equipment as well • Voltage support: ability to control reactive power, thereby ensuring that power will flow from generation to load • Black-start capability: ability to start generation without an outside source of power; this service allows to provide auxiliary power to other generation sources that could take a long time to restart Of course, the capability of providing these ancillary services depends on the storage capacity The full set of ancillary benefits described above refers to schemes with reservoirs Run-of-river schemes, with little or no impoundment, just contribute to the ‘base load’ generation, producing relatively low-value base power and offering few of the ancillary benefits listed above 6.01.2.1.3 Pumped-storage plants Pumped-storage plants are particularly well suited to manage peaks in electricity demand and to assure reserve generation In this role, they also have a remarkable environmental value: without pumped storage, to cope with unexpected peak demand or sudden loss of generating power, many thermal plants should operate at partial load as reserve generators, with increased fuel consumption and GHG emissions They also have great capability of load leveling because they can absorb power when the system has an excess Pumped-storage plants are therefore very effective means of improving ancillary services, thus playing a vital role for the reliability of electricity systems in an increasingly deregulated power market Hydro Power Base load options with limited flexibility Intermittent options that need a bcakup production 267 250 205 200 150 100 50 ov So ol la ta r ic W in d es Bi try om wa as st s e N uc l C sc oa ru l w bb ith in g (d SO 2, C oa H of ydr -ri o ve r nru 39 27 lie ar c el om Na ive b tu ry ine ral 20 d c ga (H 00 yc s km le fro m ) ga s Fu re e fo l c rm el in l g) pl Bio an m ta as tio s n H yd re ro se wi rv th oi r 16 fo r 11 ot Energy output /energy invested 300 Base and peak load options ph Bars indicate values that should be representative of the northeastern region of North America, for existing technologies The range of values, showed by black lines, Indicates the spread of all values found in the literature These values are representative of different energy systems everywhere in the world Figure Energy payback ratio: comparison among different options Table Energy technologies and generating costs Technology Biomass energy Electricity Heat Ethanol Wind electricity Solar photovoltaic electricity Solar thermal electricity Low-temperature solar heat Hydroelectricity Large Small Geothermal energy Electricity Heat Marine energy Tidal Wave Current Costs in US$ 5–15 ¢ kWh−1 1–5 ¢ kWh−1 8–25 $ GJ−1 5–13 ¢ kWh−1 25–125 ¢ kWh−1 12–18 ¢ kWh−1 3–20 ¢ kWh−1 2–8 ¢ kWh−1 4–10 ¢ kWh−1 2–10 ¢ kWh−1 0.5–5 ¢ kWh−1 8–15 ¢ kWh−1 8–20 ¢ kWh−1 8–15 ¢ kWh−1 Pumped-storage plants have some distinctive features in comparison with conventional hydropower plants: • • • • Greater output can be obtained with smaller reservoirs They not need natural inflow to the reservoirs They can be built with considerably fewer hydrological and topographical restrictions Their impact on the surrounding ecosystems is comparatively less Hydro Power – Introduction 6.01.2.1.4 GHG emissions The links between production of energy and climate change are now understood, and GHG emissions, mainly produced by burning fossil fuels, are known to contribute to global warming Hydropower tends to have a very low GHG footprint As water carries carbon in the natural cycle, all ecosystems (especially wetlands and seasonally flooded areas) emit GHG If the watershed contains a man-made reservoir, the preimpoundment emissions of the area would need to be compared with the emissions after the formation of the reservoir Studies in North America showed that hydropower reservoirs tend to increase the emissions marginally and a value of 10 000 ton TWh−1 of CO2 equivalent has been allocated to schemes in this region Because of a lack of data confirming the situation in warmer and tropical climates, a larger value (40 000 ton TWh−1) has been proposed as an international average value for hydropower Even so, hydropower GHG emissions amount to only a few percent of any kind of conventional fossil-fuel thermal generation (Figure 9) [6] The evaluation of the net GHG emissions from reservoirs is becoming more and more important for CO2 credits evaluation, and there is a growing concern to determine the contribution of freshwater reservoirs to the increase of GHG emissions in the atmosphere Therefore, it is important to continue the efforts for a better understanding and a quantitative definition of the subject 6.01.2.1.5 Environmental and social problems Environmental concerns and problems related to dams and reservoirs are one of the main reasons emphasized by the opponents However, they are now a much-studied process Great efforts have been taken to understand them and to devise measures to avoid or rectify negative consequences These efforts resulted in a much greater knowledge and in the development of a broad range of mitigation strategies The integration of environmental and social considerations in the planning, design, and operation of dams is now a standard practice in many countries The analyses of possible problems and a comprehensive negotiation processes with all the involved stakeholders greatly improved the development effectiveness of the projects by eliminating unfavorable projects at an early stage Even the World Commission on Dams, who concluded that hydropower schemes had often environmental or social unaccep­ table costs, did not recommend that hydropower should be discouraged, or that only small schemes should be developed Instead, an inclusive process was recommended in the planning, development, and management of the schemes It must also be noted that many well-conceived schemes have seen unappreciated service for several generations Some sites have been chosen as sites of special scientific interest because of the ecosystems that have become established in the reservoir areas 6.01.2.2 Hydropower Development Only one-third of the world’s potential of hydropower resources have so far been developed Figure 10 points out that while in Europe and North America almost all the technically and economically feasible hydropower potential has been harnessed, a large unexploited hydropower potential is available in Asia, where the current production is less than one-third of the potential, and in Africa, where the ratio is even smaller Base and peak load options Base load options with limited flexibility Intermittent options that need a backup production 1200 974 Kt eq CO2 TWh−1 1000 778 800 778 664 600 511 400 200 118 15 l oa C l n- H of yd -ri ro ve r y av l oi He ru se ie D H yd re ro se wi rv th oi r 15 r ea l s el ga cl l c g) al cle ue rmin Nu ur cy t F fo Na ined re b as m g o c m fro (H 13 s as n om tio Bi nta a pl r la So ltaic o v to nd i W o ph Bars indicate values that should be representative of the northeastern region of North America, for existing technologies The range of values, showed by black lines, indicates the spread of all values found in the literature These values are representative of different energy systems everywhere in the world Figure GHG emission: comparison among power generation options 10 Hydro Power 4000 Key (TWh yr −1) Technical feasibility 3500 Current production Realistic development 3000 2500 2000 1500 1000 South America N+C America Europe Australasia Asia Africa 500 Figure 10 Hydropower potential: feasible vs exploited 6.01.2.2.1 Where the hydropower potential has been exploited In most of the countries where the hydro-potential has been extensively harnessed, the hydropower development started one century ago and many dams and plants are therefore old In these countries, the focus is therefore on • maintaining the ageing works in safe and efficient conditions; • managing new requirements and needs, minimizing the negative impact on the power production; and • getting the most out of the existing infrastructures 6.01.2.2.1(i) Safety and efficiency of the existing dams and reservoirs The modernization of existing power plants is motivated and economically supported by the consequent addition of more efficient production However, maintaining existing dams and reservoirs in good and safe conditions may require important and expensive remedial works conflicting with the available resources and the duration of the concessions The recurring problems are those related to the considerable length of service of many works: • Obsolete dam typologies, not corresponding to the current state of the art • Dams designed using design criteria not fully compatible with current more demanding safety standards • Ageing and degradation process, among which expansive phenomena in concrete are having an increasing importance • Silting of reservoirs, with problems for the proper working of outlets and intakes, and additional loads applied to the structures Hydropower reservoirs can generally be filled by sediments to a higher percentage than nonhydropower reservoirs, as they are mainly addressed to maintain the head for the power generation, but silting remains a problem requiring in many cases important works for sediment removal Furthermore, many countries have to face the problems of renewing the dam engineering profession, preserving the available experience, and transmitting it to young engineers 6.01.2.2.1(ii) Additional purposes/requirements During the operating life of hydroelectric dams and reservoirs, new requirements are often introduced in addition to the initial sole hydroelectric purposes, such as flood protection, irrigation and potable supply, discharge for minimum vital flow, recrea­ tional purposes and touristic development, and wetland habitat The new needs introduce limitations and constraints in the use of the water often conflicting with the optimization of the power production Some additional requirements apply only to some dams and reservoirs, depending on the capacity of the reservoirs and the local situation and needs The requirement of a continuous water discharge to assure the minimum vital flow and to improve the downstream ecological condition apply to many dams, potentially to all, and it can reduce the electrical production of a significant amount on a national scale (in Europe, e.g., the reduction could be estimated around 10%) Consequently, the introduction of this requirement is stimulating significant activities for the installation of mini-hydro turbines to generate a continuous discharge, thus mitigating the negative impact on Hydro Power – Introduction 11 power production A significant example of additional requirement is the use for flood mitigation of the hydroelectric reservoirs in the Paraná Basin (Brazil) [7] In this basin, there is a large integrated reservoirs system (46 reservoirs) The installed capacity is >45 000 MW, including the Paraguayan share of Itaipú Initially, the majority of the reservoirs were dimensioned for hydroelectric purpose only Flood control operations were not foreseen at that time Later on, flood control rules were established for all power plants Maximum outflow constraints were set for each reservoir and a flood-forecast system was developed, thus entailing social and economic benefits through the reduction of flood impacts in the downstream areas A trade-off between flood control and energy production was consequently defined, since for the electric production it would be desirable to keep the reservoirs at their maximum capacity 6.01.2.2.1(iii) Getting the most out of existing infrastructures Where most of the hydro-potential has been harnessed and further development is limited to rather marginal contributions, the current focus is not on building new dams but rather tapping existing ones for their hydroelectric potential and getting the most out of existing infrastructures This is accomplished through a variety of engineering strategies including: • • • • • Upgrading existing schemes and extending their operational life to take advantage of the long life of the civil structures Optimizing the output of the plant to meet the needs of the power market Adding capacity for extra generation when high flows are available Adding small hydro facilities to generate the discharge for the minimum vital flow Adding hydropower capabilities at nonpower dams The addition of hydropower capabilities at nonpower dams is an important option because the large majority of the dams in the world not have a hydroelectric component For instance, a resource assessment carried out 10 years ago by the US Department of Energy concluded that in the United States a hydro-capacity of about 20 000 MW could be gained by adding generating units to about 2500 existing dams More than 70 of such projects are currently in progress, with a collective potential of over 11 000 MW [8] 6.01.2.2.2 Where large hydropower potential has still to be exploited As far as concerns, the countries with a large hydro-potential are still to be developed; in Asia and in South America, the development is driven by leading countries with important economic growth (China, Brazil, India, etc.) In Africa, where 65% of the population does not have access to electricity and the needs are consequently very urgent, only a very small amount of the hydroelectric potential has been harnessed After a period of difficulty, international lenders are now supporting dams and reservoirs and several important declarations have been recently adopted in favor of hydropower At the World Water Forum in Kyoto 2003, the most substantial effort to address the global warming problem, the Ministerial Declaration of 170 Countries stated “We recognize the role of hydropower as one of the renewable and clean energy sources, and that its potential should be realized in an environmentally sustainable and socially equitable manner.” The 2004 Political Declaration adopted at the ‘International Conference for Renewable Energies’ acknowledged that renewable energies, including hydropower, combined with enhanced energy efficiency, could contribute to sustainable development, providing access to energy and mitigating GHG emission At the 2004 UN Symposium on ‘Hydropower and Sustainable Development’, the representatives of national and local governments, utilities, UN agencies, financial institutions, international organizations, nongovernmental organizations, scientific community, and international industry associations have concluded with a strongly worded declaration in support of hydropower Many important key points are clearly stated in this declaration Warmly recommending the reading of the full declaration, some points are resumed hereinafter: • the acknowledgement of the contribution made by hydropower to development, and the agreement that the large remaining potential can be harnessed to bring benefits to developing countries and to countries with economies in transition; • the need to develop hydropower, along with the rehabilitation of existing facilities and the addition of hydropower to present and future water management systems; • the importance of an integrated approach, considering that hydropower dams often can perform multiple functions; • the acknowledgement of the progress made in developing policies, frameworks, and guidelines for evaluation and mitigation of environmental and social impacts, and the call to disseminate them Finally, in November 2008, a ‘World Declaration – Dams and Hydropower for African Sustainable Development’ has been approved by the African Union, the Union of Producers Transporters and Distributors of Electric Power in Africa, the World Energy Council, the International Commission on Large Dams, the International Commission on Irrigation and Drainage, and the International Hydropower Association (IHA) This World Declaration points out that current condition is now ripe for hydropower development in Africa A new political commitment will exist today, and more projects are under development, as shown in Figure 11 The Grand Inga project is a clear example of the tremendous potential available in Africa: a high power capacity project (up to 100 000 MW) with small impacts on environment, generating >280 TWh yr−1 of exceptionally cheap electricity 12 Hydro Power 7000 6000 MW 5000 4000 3000 2000 1000 1999 2000 2001 2003 2004 2005 2006 Year Capacity under construction 2007 Figure 11 Trend in hydropower capacity under construction in Africa 6.01.2.2.3 Hydropower in integrated water resources management Worldwide there is a major focus on integrated water resources management, highlighting the multiple benefits of dams and reservoirs Nowadays, it is not acceptable simply to maximize the economic profits of a hydroelectric scheme Closer linkages are required between water and energy resources, and the increasing need for water management is a main driver for hydro development Integrated Water Resources Management provides both a framework for sustainable reservoir management and a context in which the impacts and true value of a dam may be assessed It requires that scheme design and operation be considered at the catchment scale Management must take into account multiple objectives, including both economic and noneconomic benefits 6.01.2.2.4 International cooperation There is an increase in international and regional cooperation for hydropower development For example, companies from some Asian countries, well experienced in hydro development, such as China and Iran, are investing in schemes in Africa In South and East Asia, a number of binational developments are moving ahead, based on power purchase agreement, enabling some of the less developed countries to gain economic benefits from exporting their hydropower production In developing markets, interconnec­ tion between countries and the formation of power pools will build investor’s confidence The critical importance of international cooperation in the development of the water resources of Africa is evident, considering that Africa has 61 international shared rivers, whose basins cover about 60% of the surface of the continent As an example, the West Africa Power Pool Project is the vehicle designed to ensure the stable supply of electricity to member countries of the Economic Community of West Africa States, beginning with four member nations, namely Niger, Ghana, Benin, and Togo The first phase of the project is a 70 km line linking Nigeria to the Republic of Benin 6.01.2.2.5 Guidelines In the final declaration adopted at the 2004 UN Symposium on ‘Hydropower and Sustainable Development’, the dissemination of good practice and guidelines was recommended With regard to this, it is worthwhile to mention the ‘Sustainability Guidelines’ developed by the IHA to promote greater consideration of environmental, social, and economic aspects in the sustainability assessment of new projects and in the management of existing power schemes The guidelines define general principles that need of course to be adapted to the specific context and unique set of circumstances of each particular project The Sustainability Guidelines were formally adopted in 2003 by the IHA membership, which spans 82 countries Subsequently, they have been submitted to international funding agencies and UN organizations, with the proposal that they are used in the evaluation of future projects and in the screening of applications for credit relating to existing schemes Supplementing the guidelines is an ‘Assessment Protocol’ that sets out a system by which sustainability performance can be measured 6.01.3 Volume Presentation Purpose of the volume Volume of the Comprehensive Renewable Energy edition is dedicated to Hydropower The contribution of hydropower in the generation of electricity is important, representing around 18% of the total electricity generation and 80% of the generation of renewable electricity It needs a volume Table List of contributions of authors and affiliations Introduction Constraints of Hydropower Development Management of Hydropower Impacts through Construction and Operation Large Hydropower Plants in Brazil Overview of Institutional Structure Reform of the Cameroon Power Sector and Assessments Recent Hydropower Implementations in Canada Hydropower: A Multibenefit Solution for Renewable Energy Hydropower Schemes in the World The Three Gorges Project in China André Lejeune Samuel L Hui University of Liège Bechtel Belgium USA Carlos Matias Ramos, Margarida Cardoso da Silva Laboratório Nacional de Engenharia Civil (LNEC) University of Dresden Portugal Germany Intertechne University of Yaoundé Brazil Cameroon École Polytechnique de Montréal Canada Hohai University Changjiang Institute of Survey, Planning, Design and Research Former Director Technical NHPC Ltd., India Consultant Iran Water and Power Resources Development Company (IWPCO) Electric Power Development J-Power Iberdrola University of Burgos China Hans B Horlacher Thorsten Heyer Brasil Pinheiro Machado Joseph Kenfack Oumarou Hamandjoda Musandji Fuamba Tew-Fik Mahdi Lisheng Suo, Xinqiang Niu Hongbing Xie The Recent Trend in Development of Hydro Plants in India Siba Prasad Sen Hydropower Development in Iran: Vision and Strategy Hydropower Development in Japan Evolution of Hydropower in Spain Eisa Bozorgzadeh 10 11 12 13 14 15 Design Concept Hydropower in Switzerland Long-Term Sediment Management for Sustainable Hydropower Durability Design of Concrete Hydropower Structures Pumped-Storage Hydropower Developments 16 Simplified Generic Axial-Flow Microhydro Turbines 17 Development of a Small Hydroelectric Scheme 18 Recent Achievements in Hydraulic Research in China Toru Hino Arturo Gil García Francisco Bueno Hernandez Bernard Hagin Benjamin J Dewals Franỗois Rulot, Sộbastien Erpicum, Pierre Archambeau, Michel Pirotton Jianxia Shen Toru Hino André Lejeune Adam Fuller Keith Alexander Peter Mulvihill Ian Walsh Jun GUO University of Liège Jiangsu Provincial Water Investigation, Design and Research Institute Electric Power Development J-Power University of Liége Canterbury University Pioneer Generation Opus International Consultants China Institute of Water Resources and Hydropower Research (IWHR) India Iran Japan Spain Switzerland Belgium China Japan Belgium New Zealand New Zealand 14 Hydro Power Instead of rewriting an already existing textbook about hydropower, it was decided to enhance the progress and development of hydropower by remarkable worldwide examples or projects The volume is divided into three main sections: • Constraints of hydropower development • Hydropower schemes in the world • Design concept 6.01.3.1 Contributions and Authors, Affiliations of Volume The list of the contributions of the authors and their affiliations is given in Table All the authors are highly and warmly thanked for their contributions References [1] [2] [3] [4] [5] [6] [7] [8] [9] ENERDATA (2010) Energy Statistics Yearbook France: ENERDATA ENERDATA (2010) The World Energy Demand France: ENERDATA International Energy Agency (2010) Energy Technology Perspectives France: IEA United Nations (2010) The Millennium Development Goals Report 2010 New York, NY: United Nations World Energy Council (2007) Survey of Energy Resources 2007 London: WEC International Hydropower Association (2004) Sustainability Guidelines London: IHA Carvalho E (2001) Flood Control for the Brazilian Reservoir System in the Paraná River Basin Oxfordshire: IAHS Bishop N (2008) Waterways International Water Power and Dam Construction, June British Petroleum (2009) Statistical Review of World Energy 2010  ... Jinping-I Hydropower Pubugou Goupitan Boguchan China China China China China 12 60 0 400 300 800 800 2005 20 06 2 001 20 06 2007 2015 2015 2009 2017 2014 China China China China China Russia 200 200 60 0... 000 000 20 06 2002 2005 2004 2003 1980 2010 2012 2014 2010 2011 2012 Key Features of Hydroelectric Power After more than a century of experience, the strengths and weaknesses of hydropower are... kWh−1 2–8 ¢ kWh−1 4–1 0 ¢ kWh−1 2–1 0 ¢ kWh−1 0. 5–5 ¢ kWh−1 8–1 5 ¢ kWh−1 8–2 0 ¢ kWh−1 8–1 5 ¢ kWh−1 Pumped-storage plants have some distinctive features in comparison with conventional hydropower