ENERGY AND WATER
Presentation to
NREL Energy
Analysis Forum
Dr. Allan R. Hoffman
U.S. DOE & Winrock
International
11 June 2003
WATER SECURITY
Water security is the ability to
access sufficient quantities of
clean water to maintain
minimal standards of food and
goods production, sanitation
and health
The Water-Energy Nexus

Central to addressing water
security issues is having the
energy to extract, transport,
manage, treat and desalinate
water resources.

Water and energy issues are
inextricably linked.
The Role of Water

Water has always been
mankind’s most precious
resource.

There are no substitutes, and
the struggle to control water
resources has shaped our
political and economic history.
The Role of Water
(continued)

Population growth and economic
development are driving a steadily
increasing demand for new clean
water supplies.

Water is increasingly recognized as
the key environmental issue of the
21st century and the key to poverty
reduction.
What are the basic facts about
global water supply?

The earth is a water-rich planet, with
the total water supply estimated at
328 million cubic miles. Each cubic
mile contains more than one trillion
gallons.

Of the 328 million cubic miles, 317
million can be found in the oceans
(97%)
Basic Supply Facts (continued)

Another 7 million cubic miles is tied
up in icecaps and glaciers, and 3.1
million in the earth’s atmosphere

Ground water, fresh water lakes, and
rivers account for just over 2 million
cubic miles of fresh water
Basic Supply Facts (continued)

The net result is that 99.7 percent of
all the water on earth is not available
for human consumption.

Of the remaining 0.3 percent much is
inaccessible. The vast majority of
water for human and animal
consumption, much less than 1
percent of the total supply, is stored
in groundwater.
Water and Conflict

Water is not distributed uniformly
around the globe, and has been a
source of tension wherever water
resources are shared by neighboring
peoples.

Globally, there are more than 250
water bodies shared by more than
one country.
SOME INTERESTING
PERSPECTIVES




“The next war in the Middle East will be
over water, not politics.” (Boutros BoutrosGhali, Secretary General, United Nations)
“The only matter that could take Egypt to
war again is water.” (Anwar Sadat,
President of Egypt)
“Water is the one issue that could drive
nations of the region to war.” (King
Hussein, Jordan)
“Many of the wars in this century were
about oil, but wars of the next century
will be about water.”(Ismail Serageldin,
Vice President, World Bank)
How Is Water Used Today?


Water use is increasing everywhere.
World water demand has more than
tripled over the past half century.
On a global basis, approximately
70% of all available fresh water is
used for agriculture.



Africa: 88%
Europe: 33%
USA: 39%
How Is Water Used Today?
(continued)

Over pumping of groundwater by the
world’s farmers exceeds natural
replenishment by more than 160
billion cubic meters per year.

Water shortages now plague almost
every country in North Africa and the
Middle East
What are the sanitation and
health impacts of limited
water supplies?



Over a billion people today lack
access to clean drinking water in the
developing world, and nearly 2.5
billion lack access to adequate
sanitation services.
These numbers will grow in the years
ahead.
Water-related diseases are a growing
human tragedy, killing more than 5
million people each year.
Sanitation and health impacts
of limited water supplies
(continued)



Every day, easily prevented diarrheal
diseases cause some 6,000 deaths,
mostly children under 5.
Diarrheal diseases have killed more
children in the past 10 years than all
the people lost to armed conflict
since World War II.
About 60 million children annually
reach maturity stunted due to severe
nutrient loss and complications from
multiple diarrheal episodes.
Implications For U.S. Strategic
Interests




Shortages of water can lead to conflict in many
parts of the world where water is a transboundary
issue, creating national security problems for the
United States
Water allocation can be a vehicle to engage regional
parties in constructive dialogue
Sustainable global economic development is major
U.S. foreign policy goal. Water and energy are the
critical elements of sustainable development.
U.S. experience with water resources and their
effective management leads the world. Worldwide
market in water technologies estimated at $300
billion in the next decade.
How is Water Used in the US?


Total fresh and saline withdrawals: 402
billion gallons/day
Categories of use:







Irrigation: 39%
Thermal power plant cooling: 38%
Residential: 8%
Commercial: 3%
Industrial: 8%
Livestock: 2%
Other public use: 2%
(Note: latest available data is in USGS Circular 1200: “Estimated
Use of Water in the United States in 1995”)
U.S. Water Supply Problems


Chemical contamination of surface and
groundwater, as caused by agricultural,
industrial and defense related activities
over the past century has been recognized
as an important and widespread problem
Biological contamination of drinking water,
often associated with isolated septic tank
or wastewater discharges, has received
more attention recently and is now the
subject of important changes proposed for
U.S. drinking water regulations.
U.S. Water Supply Problems
(continued)

Sea water desalination is being
implemented in Tampa, Florida as
part of a master plan to provide new
water (10% by 2008) to a region
whose groundwater resources can no
longer supply the growing urban
demand.

The Ogallala fossil water aquifer in
the Central Plains, with no effective
recharge, is being depleted by
agricultural and urban extraction.
U.S. Water Supply Problems
(continued)


Reduction of CO River water
allocated to CA, resulting from
inability of competing urban,
agricultural and environmental
interests to agree on a conservation
plan to achieve the same reduction.
Increasing number of water disputes
in the eastern part of the U.S.



VA vs. MD
VA vs. NC
GA vs. FL vs. AL
U.S. Water Supply Problems
(continued)

Cooling water for thermal (fossil,
nuclear) power plants is becoming a
serious problem.

The increasing age of much of the
U.S. water supply and distribution
system will require massive
rehabilitation investments in the
coming decades (recently estimated
at $800 billion to $1 trillion).
How is the world responding
to the global problem?






A number of voices have sought to sound
the alarm for more than a decade.
World Water Forums (1997,2000,2003)
UN Millennium Summit (2000)
World Summit on Sustainable Development
(2002)
International Year of Freshwater 2003
New UN Decade of Water?
Energy Needs of Water
Services



Energy is required to:
• lift water from depth in an aquifer
• pump water in pipes
• treat waste water
• desalinate brackish or sea water
Globally, commercial energy consumed for
delivering water is more than 26 quads, 7
percent of total world consumption.
A considerable amount of water is also
delivered by utilization of human energy –
e.g., use of treadle pumps and water
transport by women and children.
Water-Energy Use in
California:
An Interesting Example

Energy demand associated with water use
in CA is high for three reasons:





most of demand is located at considerable
distance from source
water is heavy and moving it is energy intensive
water used for consumption must be treated,
another energy intensive process
Annual water consumption is over 40
million acre-feet (one acre-foot =
326,000 gallons)
Energy required annually to pump and treat
water exceeds 15,000 GWh, approximately
6.5% of total electricity used in the state
per year
Water-Energy Use by Power
Plants

Cooling water for thermal power plants is
the second largest user of fresh water in
the U.S., second only to water used for
agricultural irrigation

Estimated use is 190 million gallons per day

A 500 MW closed-loop plant requires 7,000
gallons per minute (10.1 million gallons per
day)
Energy Needed to Lift Ground
Water
Power = (water flow rate) x (water density)
x (head)
Example: Lift water from a depth of 100 feet at a
flow rate of 20 gallons/minute (0.045
cubic feet/sec), assuming an overall
pump efficiency of 50%
Power = (2) x (0.045cfs) x (62.4lb/ft3) x (100ft)
= 562 ftlb/sec = 1.0 HP
Energy Needed to Transport
Water



Depends on the diameter and length of pipe used
In general, use pipe where water velocity is 3-5 feet/sec
and water pressure in pipe stays in nominal range
Power = (water flow rate) x (water density)
x (H + HL)


H is lift of water from pump to outflow (positive if pumping
uphill and negative if pumping downhill), and
HL is the effective head loss from the water flow in the pipe:
•
•
•
•
•
•
HL = (F) x (L/D) x (V2/g)
F = friction coefficient (from table)
L = length of pipe
D = diameter of pipe
V = water flow rate
g = acceleration due to gravity (32.2 ft/sec2)
Energy Needed to Transport
Water
(continued)
Example: Move water uphill 100 feet at 3 feet per
second through a pipeline that is 1 mile
long (5,280 feet) and 2 inches (0.167
feet) in diameter (F=0.025). Flow rate
is 29.5 gpm (0.066 cfs).
HL = (0.025) x (5,280 ft) x (1/0.167) x (32) x
(1/32.2) = 221 ft
Power = (2) x (0.066) x (62.4) x (100 + 221)
= 2,644 ftlb/sec = 4.8 HP
Energy Needed to Treat Water



Most water treatment options require energy levels
of 2-3 feet of head. At a given flow rate, you can
use the first example (slide # 25) to calculate the
power required. This number would cover options
such as simple filtration or ion exchange.
An operation such as ozonization is more dependent
on water quality and can require more energy.
Average energy use for water treatment drawn from
Southern California studies: 652 kWh/AF
Note: in many remote parts of the world, treatment
must be very basic and inexpensive. This requires a
different approach to treatment than implied above.
Energy Needed for
Desalination

Reverse Osmosis:




Pressure (200-600psi) applied to intake water, forcing
water through semi-permeable membrane. Salt
molecules do not pass through membrane. Product
water is potable.
On average, energy (electrical) accounts for about
40% of total cost.
5,800-12,000 kWh/AF (4.7-5.7 kWh/m3)*
Distillation:
Intake water heated to produce steam. Steam
condensed to produce product water with low salt
concentration.
 Energy requirements for distillation (electrical +
thermal) are much higher than for reverse osmosis.
 28,500-33,000 kWh/AF (23-27 kWh/m3)*
-----------------------------------------------------------------
* Does not include energy required for pre-treatment, brine disposal and water transport.
Implications for Global Energy
Supply

It is now widely recognized that water and
sanitation are inextricably linked to the
eradication of poverty and the achievement
of sustainable economic development

As a result, the UN has adopted two related
Millennium Development Goals:


reduce by half,
without access
reduce by half,
without access
by 2015, the proportion of people
to safe drinking water
by 2015, the proportion of people
to basic sanitation
Implications (continued)

Today more than 1 billion people lack access to safe
drinking water (17%) and nearly 2.5 billion lack
access to adequate sanitation (41%).

Estimated world population in 2015: 7.2 billion

In order to reach the Millennium Development
Goals:
 1.7 billion more people will need to be supplied
access to safe drinking water
 2.2 billion more people will need to be supplied
access to basic sanitation
 These are large numbers, and the challenge to
reach the Millennium Development Goals will be
immense.
Energy System Implications

The kind of energy system chosen to provide water
for drinking and sanitation will be a function of local
circumstances:





What kind of water resources are available, locally and
at a distance (local wells, streams, lakes, aquifers,
water that can be piped from a distance)?
What is the quality of those resources, and what
treatment will be required to make the water safe to
use(fresh or brackish water, pollution level and nature
of pollutants)?
What energy resources are available(grid, diesel,
renewable,human)?
What financial resources are available to provide the
needed water infrastructure and related energy needs
What level of training is needed to maintain water and
energy systems?
Concluding Remarks






The problem of global water security is
already serious and is growing more
serious each year
Global water security issues impact U.S.
strategic interests
World attention is finally beginning to focus
on water security issues
The U.S. is not immune to water security
problems
Much can be done to address the growing
crisis
It will take time and lots of resources
Concluding Remarks





Considerable effort must be expended to
identify and characterize water resources,
and design supply systems appropriate to
local circumstances
Water issues cannot be separated from
energy issues
Careful effort must be expended to identify
appropriate energy options needed to meet
water security needs
A major analytical effort is needed to
identify the steps needed to meet the
Millennium Development Goals
Achievement of these goals will still leave
billions of people without water security.