lecture 9: sectors Flashcards
what are the current global water demand by sector?
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.
Current Global Water Demand – Current Trend
• 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.
Future Global Water Demand
• 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
Future Global Water Demand
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
What is the water, food, energy and health nexus
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water and health
• 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
what is the global picture of water associated disease
• 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.
Distribution of Water Associated Disease
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.
Percentage of deaths among children under age
5 attributable to diarrhoea, 2015
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Types of Water Associated Disease
Water-associated disease can be classified into one of the following five categories:
- 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. - 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. - Water-related diseases, such as malaria and trypanosomiasis, need water for
breeding of insect vectors to fulfill the transmission cycle. - Water-washed diseases are those whose transmission is due to poor personal
and/or domestic hygiene as a result of lack of appropriate water. - 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.
Distribution of reported outbreaks of waterassociated
infectious diseases
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Transmission Routes
what is schitosomisis- bb
• 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
what progress have we made towards the mdgs- water and sanitation
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improved access to facilities
sanitation
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what is global water use and pollutants?
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what are examples of ubiquitous water pollutants
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what is water for energy
- cooling of thermoelectric power plants
water treatment
hydropower
water power
Energy for Water: Energy Requirements
for Water Provision
• 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
water for energy
• 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).
electricty generation and water
• 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
Links between water- energy demand
• 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
• 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
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current and future energy demand for electrity
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
Implications of Future Changes in
Electricity Demand for Water
• 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.
Example - Desalinization
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
Example - Hydraulic Fracturing
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.
Example - Biofuels
• 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
global distribution of power plant types
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Thermoelectric Power Production and Water
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.
Thermoelectric water cooling
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Thermoelectric Power
Production Water Use
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.
As aside- water and carbon footprints of power production
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hydropower
• 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.
Hydropower trends
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.
Climate risks to Electricity Generation
• 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
Climate Risks to Electricity Generation
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.
Future Climate Risks to Electricity Generation
• 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
An Example of Wider Implications:
Climate-Electricity-Emissions Connections
• 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
An Example of Climate-Electricity-Emissions
- Impact on Production
• 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
An Example of Climate-Electricity-Emissions
- Impact on Retail Electricity Price
• 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
An Example of Climate-Electricity-Emissions
- Impact on GHG Emissions
When drought curtails hydroelectric energy
production, demand must be met by
switching to other sources – often natural
gas, with conseque
The Water–Energy–Food nexus
• 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.
The Effects of Increasing Food Demand on
Water (and Energy)
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
The Water–Energy–Food Nexus -
Synergies and Trade-Offs
• 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.
Historical changes in irrigated areas
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Past and Future Changes in South Asian (Indian)
Irrigated Land
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
Water-Energy Food
Conflicts
An Example from
Central Asia
• 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.
