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 6

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 0 to 1.
Hydropower resource Hydropower resource can be
measured according to the amount of available power, or
energy per unit time.

1

4

6

6

6

7

9

9

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 1 million kilowatt-hours; 1 GWh is sufficient to
power approximately 89 US homes for 1 year or 198 homes in the European Union for 1 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 6

doi:10.1016/B978-0-08-087872-0.00601-6

1


2

Hydro Power

60 000
Natural gas
Oil
Coal
Nuclear
Hydro

50 000

TWh

40 000

30 000

20 000

10 000

0
1965 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004
Figure 1 Historical trend in world’s primary energy consumption by source, 1965–2006 (1 TWh = 1 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
0
1971

Europe
1975

1979

1983

1987

1991

1995

1999

2003

2007

Figure 2 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 2 [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 3 [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%

3

USA
22%

CIS
7%
EU-27
17%

China
16%
Asia+Pac
(exc. China)
19%
Figure 3 Electricity generation by region.

2007

Oil

2015

Biomass

2030
Other renewables
Nuclear
Hydro
Gas
Coal

0

4 000

8 000

12 000

16 000

TWh
Figure 4 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:
1.
2.
3.
4.
5.
6.
7.
8.

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 5 and 6 [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 1. 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 2. 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

0
1971

1975

1979

1983

1987

1991

1995

1999

2003

2007

Figure 5 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
0
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007


OECD

0

1971

Figure 6 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 7 Hydroelectricity production by region.

Table 1

Largest hydroelectric dams and plants in operation

Capacity
(MW)

Max annual
production
(TWh)

17 600 a
14 000
10 200
8 370
6 809
6 400

> 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

6 000
5 616
5 429
4 500
4 320
4 050

2009
1976
1999
1974
1994/1997
1988
1979/1988

3 500 b
3 478
3 300
3 200
3 162
3 115
3 000

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

5


6

Hydro Power

Table 2

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
6 400
6 300
5 800
4 800

2005
2006
2001
2006
2007

2015
2015
2009
2017
2014

China
China
China
China
China
Russia

4 200
4 200
3 600
3 300
3 000
3 000

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 3

7

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

9
ov So
ol la
ta r
ic

W

in
d

5

3

es Bi

try om
wa as
st s
e

4

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

5

0
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

8

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 8 Energy payback ratio: comparison among different options.

Table 4

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 do 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

9

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

0

15

1
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

9
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 9 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

0

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 do 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
0

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 6 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 5
1
2

List of contributions of authors and affiliations

Introduction
Constraints of
Hydropower
Development

3

Management of Hydropower Impacts through
Construction and Operation

4
5

Large Hydropower Plants in Brazil
Overview of Institutional Structure Reform of the
Cameroon Power Sector and Assessments
Recent Hydropower Implementations in Canada

6
7

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

8

The Recent Trend in Development of Hydro Plants in
India

Siba Prasad Sen

9

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 François Rulot, Sébastien
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 6

The list of the contributions of the authors and their affiliations is given in Table 5.
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.