lecture 9: sectors

Question 1

what are the current global water demand by sector?

Answer 1

Agriculture
• Agriculture accounts for 70% of total freshwater withdrawals globally, with the
industrial and domestic sectors accounting for the remaining 20% and 10%,
respectively, but with considerable variation across countries.
• More-developed countries have a much larger proportion of freshwater
withdrawals for industry than less-developed countries, where agriculture
dominates. Agriculture accounts for more than 90% of freshwater withdrawals in
most of the world’s least-developed countries (LDCs).
Energy
• Traditionally embedded in the industry sector in terms of accounting. Global
water withdrawals for energy production account for about 15% of the world
total, or roughly 75% of all industrial water withdrawals
Ecosystems
• There is less systematic information on where and to what extent the
maintenance of environmental flows has actually been applied, despite the
needs.

Question 2

Current Global Water Demand – Current Trend

Answer 2

• Globally, total freshwater withdrawals are believed to have increased by
about 1% per year between 1987 and 2000,
• Annual freshwater withdrawals appear to have stabilized or even
declined in the majority of the world’s most highly developed countries
• This suggests improvements in efficiency and increasing reliance on the
importation of water intensive goods, including food.
• This also suggests that the 1% annual global increase has been
occurring almost exclusively in developing countries.

Question 3

Future Global Water Demand

Answer 3

• Global demand is expected to grow significantly for all major water
sectors
• The largest growth occurring in developing or emerging economies
• Quantifying this demand is extremely difficult because of uncertainties
about the amount of water required to meet the growing demand for
food, energy and other human uses, and to sustain ecosystems
• Without improved efficiencies, agricultural water consumption is
expected to increase by about 20% globally by 2050.
• Domestic and industrial water demand are also expected to rise,
especially in cities and countries undergoing accelerated economic
growth and social development.
• Water demand for energy is expected to increase by more than onethird
up to 2035 with 90% of this outside the OECD

Question 4

Future Global Water Demand

Answer 4

Global water demand in terms
of water withdrawals is projected to
increase by 55% due to growing
demands from manufacturing
(400%), thermal electricity
generation (140%) and domestic
use (130%)

This will increasingly strain water
resources with 2.3B people (40%
of current population) expected to
be living in water stressed regions

This does not take into account the
provision of environmental flows

Question 5

What is the water, food, energy and health nexus

Answer 5

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Question 6

water and health

Answer 6

• Water is fundamental to many aspects of human health

• Building blocks of public health:
Water and Health
Adequate nutrition
Safe water
Clean air
Protection from
infectious disease
Protection from
natural disasters

Solutions generally require:
• Recognition of the relationship between water and health to help make better
policy making
• Integrated Water Resources Management for human health

Question 7

what is the global picture of water associated disease

Answer 7

• Water can serve as a media for hazardous substances and pathogenic organisms,
posing substantial health threats to humans through a variety of pathways.
• Pathogenic - of a bacterium, virus, or other microorganism, causing disease.
• Worldwide, water-associated infectious diseases are a major cause of morbidity
and mortality.
• 4% of global deaths and 5.7% of the global disease burden (in DALYs) were
attributable to a small subset of water, sanitation, and hygiene (WASH) associated
infectious diseases including diarrheal diseases, schistosomiasis, trachoma,
ascariasis, trichuriasis, and hookworm infections.

Question 8

Distribution of Water Associated Disease

Answer 8

Diseases contributing to the total
disease burden caused by water,
sanitation and hygiene (WASH)

• The actual disease burden
attributable to waterassociated
pathogens is likely
to be much higher than 5.7%.
• A total of 1415 species of
microorganisms have been
reported to be pathogenic,
• About 348 are waterassociated,
causing 115
infectious diseases.
• Yet, their distribution and
associated factors at the
global scale remain largely
unexplored.

Question 9

Percentage of deaths among children under age

5 attributable to diarrhoea, 2015

Answer 9

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Question 10

Types of Water Associated Disease

Answer 10

Water-associated disease can be classified into one of the following five categories:

1. Water-borne diseases, such as typhoid and cholera, are typically caused by
   enteric microorganisms, which enter water sources through fecal contamination
   and cause infections in humans through ingestion of contaminated water. There
   are also water-carried diseases (pathogens such as Cryptosporidium, Giardia)
   whose transmission can be through accidental ingestion of, or exposure to,
   contaminated water.
2. Water-based diseases commonly refer to diseases caused by infections of
   worms which must spend parts of their life cycles in the aquatic environment,
   such as schistosomiasis.
3. Water-related diseases, such as malaria and trypanosomiasis, need water for
   breeding of insect vectors to fulfill the transmission cycle.
4. Water-washed diseases are those whose transmission is due to poor personal
   and/or domestic hygiene as a result of lack of appropriate water.
5. Water-dispersed diseases are caused by infections of agents which proliferate in
   fresh water and enter the human body through the respiratory tract, such as
   Legionella.

Question 11

Distribution of reported outbreaks of waterassociated

infectious diseases

Answer 11

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Question 12

Transmission Routes

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Answer 12

• Water plays an important role in the transmission of many infectious diseases,
which pose a great burden on global public health.
• A major source of much water associated disease is lack of sanitation and low
standards of hygiene – heavily influenced by the quantity of water available in the
home

Question 13

what progress have we made towards the mdgs- water and sanitation

Answer 13

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Question 14

improved access to facilities

sanitation

Answer 14

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Question 15

what is global water use and pollutants?

Answer 15

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Question 16

what are examples of ubiquitous water pollutants

Answer 16

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Question 17

what is water for energy

Answer 17

• cooling of thermoelectric power plants

water treatment

hydropower

water power

Question 18

Energy for Water: Energy Requirements

for Water Provision

Answer 18

• Energy is required for two components of water provision: pumping and treatment.
• Energy for pumping depends on elevation change (including depth in the case of
groundwater), distance, pipe diameter and friction.
• The amount of energy needed in water and wastewater treatment processes varies
greatly and is dependent upon factors such as the quality of the source water, the
nature of any contamination, and the types of treatment used by the facility.
• UV treatment uses little energy (0.01–0.04 kWh/m3)
• Reverse osmosis uses lots of energy (1.5–3.5 kWh/m3)

Energy cost depends on the
requirement for pumping
and for treatment

Question 19

water for energy

Answer 19

• Water is crucial for producing energy
• Water is used in the extractive industries for
producing fuels such as coal, uranium, oil and
gas.
• W
• ater is an input for energy crops such as corn
and sugar cane for ethanol and biomass for
fuel pellets.
• Water is also crucial for cooling purposes in
most power plants and the driving force for
hydroelectric and steam turbines.
• Water withdrawals and consumption vary for
fuel production.
• Energy accounts for a significant fraction of a
country’s water use (both consumptive and
non-consumptive).

Question 20

electricty generation and water

Answer 20

• Approximately 90% of global power
generation is water intensive.
• Water is used directly for hydropower
generation as well as for all forms of
thermal power generation schemes.
• Water also indirectly enables power
generation through the cooling it
provides for the vast majority of
thermal power plants.
• These plants use heat (from nuclear,
coal, natural gas, petroleum, solar or
biomass sources) to make power, and
are responsible for roughly 80% of
global electricity production

• World electricity generation by source
  of energy as a percentage of world
  electricity generation, 2011

Question 21

Links between water- energy demand

Answer 21

• Many of the external pressures that drive the increasing demands for water also
play influential roles in the growing demand for energy.
• Social development and economic growth
• Economic forces, increasing living standards, technology and policy

• Yet market forces have played a much more important role with respect to
energy sector development, whereas the management of water resources and
the improvement of water-related services have historically been more of a
socio-political prerogative.
• Progressive energy access programmes, accelerated urbanization and rapid
economic development in some developing countries have provided access to
modern energy services for hundreds of millions of people over the past two
decades, especially in China and India.
• However, nearly one-fifth of the global population, close to 1.3 billion people, did
not have access to electricity in 2010, and roughly 2.6 billion people relied on the
traditional use of biomass for cooking

Question 22

• However, nearly one-fifth of the global population, close to 1.3 billion people, did
not have access to electricity in 2010, and roughly 2.6 billion people relied on the
traditional use of biomass for cookin

Answer 22

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Question 23

current and future energy demand for electrity

Answer 23

There is evidence that demand for all types of primary
energy will increase over the period 2010–2035. With
implications for water use

Globally, electricity demand is expected to grow by
roughly 70% by 2035. is growth will be almost entirely
in non-OECD countries, with China and India
accounting for more than half that growth.
Most increases will be in renewables – wind in OECD
and hydro in non-OECD

Question 24

Implications of Future Changes in

Electricity Demand for Water

Answer 24

• The IEA’s World Energy Outlook 2012 estimates global water withdrawals for
energy production in 2010 at 583 billion m3 (representing some 15% of the
world’s total withdrawals), of which 66 billion m3 was consumed.
• By 2035, according to its New Policies Scenario, withdrawals would increase
by 20%, whereas consumption would increase by 85%, driven by a shift
towards higher efficiency power plants with more advanced cooling systems
(that reduce withdrawals but increase consumption) and due to increased
production of biofuel.

Question 25

Example - Desalinization

Answer 25

Desalination - removing salt/minerals from saline water for use by all sectors.

Example - Desalinization
There are currently more than
16,000 desalination plants
worldwide, with a total global
operating capacity of roughly 70
million m3/day. Desalinated water
involves the use of at least 75.2
TWh/year, which is about 0.4% of
global electricity consumption

Growth in desalination has increased significantly
over the past 20 years as countries seek to
augment natural water supplies and as the
combined energy and industrial costs have
reportedly dropped to below US$0.50/m3. There
is potential for capacity do double by 2020.
But remains a costly solution with local side
effects – e.g. highly saline outflows

Question 26

Example - Hydraulic Fracturing

Answer 26

Increasing energy demands and decreasing availability of conventional fuels has quickly
transformed natural gas extraction from shale formations into a potentially significant
energy solution for the coming decades. But there are potential environmental impacts,
especially due to risks affecting groundwater resources used for drinking water supply.

Question 27

Example - Biofuels

Answer 27

• The contribution of biofuels to energy supply is expected to grow rapidly, with
beneficial impacts including reduction in GHGs, improved energy security and
potential new income sources for farmers.

• But biomass
production competes
with food crops for
land and water
• In China and India this
may become a real -
they have initialed
programmes to boost
biofuel production
• Some regions e.g. EU
are reconsidering
biofuel policy because
of the adverse
impacts on land,
water and
environment

Question 28

global distribution of power plant types

Answer 28

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Question 29

Thermoelectric Power Production and Water

Answer 29

The thermal power sector is a large user of water; in Europe, it is responsible for
43% of total freshwater withdrawals and accounts for more than 50% national
water withdrawals in several countries. The thermal power sector is also the single
largest user of water in the USA, responsible for nearly half of all water
withdrawals, ahead of even agriculture.

Question 30

Thermoelectric water cooling

Answer 30

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Question 31

Thermoelectric Power

Production Water Use

Answer 31

Several factors determine how much cooling
water is needed by thermal power plants,
including
• the fuel type
• cooling system design
• prevailing meteorological conditions

More importantly, the more efficient the
power plant, the less heat has to be
dissipated, thus less cooling is required.

Older power plants tend to be less efficient
and thus consume more water.

Question 32

As aside- water and carbon footprints of power production

Answer 32

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Question 33

hydropower

Answer 33

• Hydropower is a major water user but the majority of water is returned to the river
• Hydroelectricity is currently the largest renewable source for power generation in
the world, meeting 16% of global electricity needs in 2010
• Hydro is important as it can provide stability for the electricity system because of
the short start up times.

Question 34

Hydropower trends

Answer 34

Electricity generation from recent additions to hydropower and other
renewables

Yet, the percentage of undeveloped technical potential for hydropower is highest in
Africa (92%), followed by Asia (80%), Australasia/ Oceania (80%) and Latin America
(74%).

However, only about two-thirds of estimated total technical potential is believed to be
economically feasible.

Question 35

Climate risks to Electricity Generation

Answer 35

• Increasing ambient water temperatures
and changes in overall water availability
create risks for the power sector.
• Demand for electricity could increase in a
warmer world (e.g. air conditioning)
• Power plants have had to shut down
because of lack of water for cooling
purposes or because of high water
temperatures
• Droughts threaten the hydropower
capacity of many countries
• Water availability could be a constraint for
the expansion of the power sector in
many emerging economies, especially in
Asia.

The Millstone nuclear plant in
Waterford, CT, US had to shut down
one of its reactors in mid August 2012
because the water it drew from the
Long Island Sound was too warm to
cool critical equipment outside the
core.

• There are important potential changes in the future because of changes in supply
and demand, and the consequences for GHG emissions

Question 36

Climate Risks to Electricity Generation

Answer 36

Estimated change in hydropower and thermoelectric power usable capacity for the
drought, warm year of 2003 in Europe (a) and 2007 in the Eastern North America
(b) relative to the average for 1981-2010.

Question 37

Future Climate Risks to Electricity Generation

Answer 37

• Declines in HydroP for 61-74% plants worldwide (RCP2.6-8.5)
• Global reduction of 1.2-3.6% (annual) and up to 9.6-17% (monthly) for 2050s
RCP2.6-8.5

Question 38

An Example of Wider Implications:

Climate-Electricity-Emissions Connections

Answer 38

• Thermoelectric power uses 45% of
water withdrawals in the US, 73%
from freshwater sources.
• Western US states rely largely on
hydropower and their thermoeletric
power withdrawals amounted to
15% of national total.
• The high reliance on hydropower
makes the energy sector
particularly vulnerable to droughts

Question 39

An Example of Climate-Electricity-Emissions

- Impact on Production

Answer 39

• During droughts, there is a tendency for hydro and coal to go down (both water
constrained),
• and be replaced by natural gas (often air cooled) and imports from other states
• Sometimes coal increases – maybe replacing hydro and hydro imports

Question 40

An Example of Climate-Electricity-Emissions

- Impact on Retail Electricity Price

Answer 40

• Retail electricity prices generally increase during drought
because of decline in supply
• Leading to cumulative costs in the billions of dollars
• Prices may also increase because of demand increases –
such as increased air conditioning

Question 41

An Example of Climate-Electricity-Emissions

- Impact on GHG Emissions

Answer 41

When drought curtails hydroelectric energy
production, demand must be met by
switching to other sources – often natural
gas, with conseque

Question 42

The Water–Energy–Food nexus

Answer 42

• Water is an input for producing
agricultural goods in the fields and
along the entire agrifood supply
chain.
• Energy is required to produce and
distribute water and food: to pump
water from groundwater or surface
water sources, to power
agricultural machinery, and to
process and transport agricultural
goods.
• Agriculture is currently the largest
user of water at the global level,
accounting for 70% of total
withdrawal.
• The food production and supply
chain accounts for about 30% of
total global energy consumption.

Question 43

The Effects of Increasing Food Demand on

Water (and Energy)

Answer 43

Estimates suggest that global food production will need to increase by as much
as 60% by 2050 to meet demand from growing population (9.3 billion ), rising
incomes, urbanization and climate change
• Achieving such a dramatic increase is a formidable challenge with significant
implications for water, and energy

Question 44

The Water–Energy–Food Nexus -

Synergies and Trade-Offs

Answer 44

• Using water to irrigate crops might promote
food production but it can also reduce river
flows and hydropower potential.
• Increasing production of crops through
fertilizers can lead to water pollution
• Growing bioenergy crops under irrigated
agriculture can increase overall water
withdrawals and jeopardize food security.
• Converting surface irrigation into high
efficiency pressurized irrigation may save
water but may also result in higher energy
use.

Recognizing these synergies and balancing these trade-offs is central to jointly
ensuring water, energy and food security.

Question 45

Historical changes in irrigated areas

Answer 45

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Question 46

Past and Future Changes in South Asian (Indian)

Irrigated Land

Answer 46

Left: change in irrigated land from 1900 to 2005.
Massive changes have happened in the last 10-
20 years because of GW pumping

Below: expected expansion of irrigated land.
This is based on increasing demand, future
climate scenarios of drier more variable rainfall
and continued use of available water resources

Question 47

Water-Energy Food
Conflicts
An Example from
Central Asia

Answer 47

• Dams in the mountains of Kyrgyzstan and
Tajikistan once collected water in autumn
and winter that was released in spring and
summer to irrigate cotton and wheat in
Uzbekistan, Turkmenistan and Kazakhstan.
• Upstream countries were compensated for
this water by cheap oil and gas from
downstream countries.
• However, rising energy prices made it
beneficial for upstream countries to generate
more hydropower in winter by releasing
water that could not then be used for
irrigation.
• As a result, downstream countries,
maintaining the same crop and production
patterns, had insufficient water in summer to
satisfy agricultural demand.

Multi-purpose dams can provide energy as
well as water for irrigation and flood
management. However, water demand for
energy production can be in conflict with water
demand for agriculture. 

Dam and reservoir management procedures, cropping
patterns, irrigation practices and compensation packages
that are agreeable to all countries involved have not yet
been achieved. There are concerns that this situation may
prompt nations like Uzbekistan to start considering
alternative water sources for irrigation, such as GW.