Water for Energy

Tucson Electric Power Com-pany has been responsible for providing energy to the great-er Tucson area for the past thirty years. They have be-come a household name and appreciated for successfully and efficiently providing en-ergy for the citizens of Tuc-son. But one thing many con-sumers do not realize is the amount of water used to bring energy to their homes. Water is probably not the first thing that comes to much when you think of an electricity company or elec-tricity in general. Every time a Tucson citizen turns on a light, they are also using wa-ter, indirectly, to create that energy. The Tucson Electric Power Company has three Tucson sites where they pro-

duce energy: Irvington (4 steam units powered by coal, 2 gas tur-bines), DeMoss Petrie (1 gas turbine) and the North Loop (4 gas tur-bines). There are also three sites located out-side of Tucson, but within the state: Springerville: Springer-ville Generating Station (4 steam units powered by coal), Nogales: Valencia Gen-erating Station (4 gas tur-bines) and Kingman: Black Mountain Generating Station (2 gas turbines). When it comes to determining the water usage of a station, gas

stations do not use a signifi-cant amount of water for it to matter. The energy that is created at these plants is gen-erated by using water. It is estimated that for every kilo-watt-hour generated 0.5-0.75 gallons of water are needed for when coal is used. When looking at it on a daily basis or per house hold it would seem miniscule compared to how much water is used for other things, but on a large

Electricity for Tucson Evan Miller and Arielle Dominguez

Water/Energy Nexus

April 26, 2012

Volume 1, Issue 1

Electricity for Phoenix Navajo Generating Plant

2

Hoover Dam Palo Verde Nuclear

3

Solano Solar Plant 4

Water for Tucson Water for Phoenix

5

Class Assignment & Energy/Water Nexus Relations

6

References 7-9

Inside this issue:

The Energy/Water Nexus:

It takes water to generate

electricity; about 3/4th of a

gallon for every kWh for

fossil fuel plants and much

less from Nuclear powered

plants.

It takes energy to deliver

water to customers; about

1900 kWh are needed to

deliver each AF of water to

Tucson from the Colorado

River.

It takes about 500 gallons of

water to generate 1 kWh of

electricity via Hoover Dam.

scale that amount of water is immense. Between 2000 and 2010, it took on average 16,235 AF of water per year to provide power to the greater Tucson ar-ea.

The burning of fossil fuels adds 1.92 pounds of carbon to the atmosphere for every kWh of energy that is produced.

Springerville Generating Station

Irvington Generating Station

Located in central of Arizona, Phoenix is surrounded by deserts and rocky mountain terrain with extremely hot weather and a lack of water. Although residents pay their power bill, many take for granted of how much energy goes into powering their homes. If power companies stopped making electricity there would be no Internet, no computers, no refrigerators, and no air condi-tioning! Two companies handle the process of turning water, coal, wind, solar energy, nuclear power, and natural gas into elec-tricity that powers Phoenix. Formed over one hundred years ago, the Salt River Project (SRP) and Arizona Public Service (APS) now provide electricity to over four million people. Both compa-nies use water to generate elec-tricity and in the past decade “Phoenix has kept its water con-

sumption to 340,000 acre-feet a year even as its population has grown.”

Drawing from the Salt River SRP was founded in 1903 and has been providing electricity for Phoenix ever since. SRP operates seven hydroelectric plants, elev-en electrical generating stations, and has agreements with major hydroelectric plants along the Colorado River. Reservoirs on the Salt River offer valuable water storage as well as a recreational spots for fishing and boating. Their main reservoir is Roosevelt Dam and Lake. When their re-sources are at their peak SRP generates around 9,000,000 kWh; 39% from hydro-power; 10% from solar energy; 14% from wind turbines; 5% in landfill gas; plus 1% produce through biomass. Although we knew that

water is used in most of these generation processes, we were unable to quantify it.

APS, founded in 1884, has ex-panded its service area from Phoenix into northern and cen-tral Arizona providing electricity to over a million people in eleven different counties. APS owns the nearly 30% of the Palo Verde Power Plant, the largest nuclear power plant in the USA. (for more details see separate article on the Palo Verde Plant which supplies more than 4,000,000 kWh to APS customers. This is supplemented by five natural-gas plants that produce upwards of 2,400,000 kWh of electricity. Recently APS has started to put solar panels in different areas around Phoenix to explore a new frontier in energy generation

Electricity for Phoenix

Navajo Generating Plant

Page 2 Water /Energy Nexus Vo lume 1, I ssue 1

750MW generators. Inside each unit is a generator, boiler, tur-bine, environmental control equipment, and a closed-cycle cooling system. Steam emitted via heated water inside the tur-bines, drives the turbines. The heat produced is removed via evaporation in six induced-draft cross-flow cooling towers. Coal is provided by the Kayenta Mine, which is transported, by the Black Mesa and Lake Powell Railroad. The station on average will consume 25,000 tons of coal in a given day at full operation. The water used at the plant is pumped directly from the neigh-boring Lake Powell. The demand for electricity in the Southwest solidifies the importance of the Navajo Generating Station to its consumers in this region. The power generated at the plant is distributed to six main divisions: the U.S. Bureau of Reclamation

at 24.3 percent, SRP at 21.7 per-cent, LA Department of Water and Power at 21.2 percent, Ari-zona Public Service at 14 per-cent, NV Energy at 11.3 percent, and Tucson Electric Power at 7.5 percent. These consumers rely heavily on the plant to provide energy to millions of people across three states. Consequent-ly the Navajo Generating Station is the thirteenth largest producer of greenhouse gasses in the country, releasing more than 19 million tons of carbon dioxide per year, equivalent to more the 3.2 million vehicles on the road. Many studies have been done is recent years to find out the exact effects that the Navajo Gener-ating Station has had on its sur-rounding environment. Its close proximity to the Grand Canyon, Glenn Canyon Dam, and Lake Powell put many natural ecosys-tems, as well as humans, at risk.

Water is used to cool electric power plants all over the country including the coal burning Nava-jo Generating Station plant in northern Arizona. In the South-west alone over 2,000 Acre-feet of water a day is used for this purpose. Typically the Navajo Generating plant consumes around a half gallon of water per kilowatt-hour of generated elec-tricity. In fact in one year the Navajo Generating Station will consume eight million tons of coal, and a staggering 28,000 mWh of water producing 2,250 mWh of electricity. The Navajo Generating Station was complet-ed in 1976 in the hopes of ful-filling the need for new electric generation in the Southwest as well as providing a large source of power for the operation of the Central Arizona Project (CAP) pumping stations. Operated by the Salt River Project (SRP), the station consists of three identical

Palo Verde Power Plant run by APS.

Roosevelt Dam run by SRP

Navajo Generating Station in Northern Arizona

Matt Barber and Luke Karnoski

Matthew Propst and Taylor Hudson

Hoover Dam

Palo Verde Nuclear Plant

Page 3 Water /Energy Nexus Vo lume 1, I ssue 1

Hoover Dam is a large dam on the Colorado River between Nevada and Arizona. It was built between 1931 and 1936. At that time, it was the largest concrete structure ever. It produces ener-gy for the states of Arizona, Cali-fornia and Nevada. The body of water held back by Hoover Dam is known as Lake Mead. Lake Mead’s water content level is 2.6 x 107 Acre Feet (AF). An AF is equivalent to 325,851 gallons or 3.258 x 105 Gal. On average, it receives 6.4 x 106 AF/year and it releases 5.2 x 106 AF of water downstream. The difference is the water lost via evaporation from Lake Mead or 1.2 x 10 6

AF/yr. The surface area of Lake Mead on average from 1942-1995 was 125,600 Acres (1.256 x 105 AC). The measured average

annual evaporation (Jan 1998-Dec 1999) was 7.5 ft., when mul-tiplied by the lake area gives a total of evaporated water of 9.4 x 105 AF/yr. This is slightly less than estimated above from the differences from flow in and flow out, but approximately the same order of magnitude. This water is no longer able to be used; it is consumed by the atmosphere via evaporation from the surface of Lake Mead.

The released water through the turbines to generate electricity averages about 5.2 x 10 6 AF/year which is equivalent to 1.6 x 10 12 Gallons/year. In one year, the water that passes through the dam’s 17 generators creates 4.2 billion kWh of electricity or 4.2 x 10 9 kWh/yr, which means that

it, requires 381 gallons to pass through the turbines to generate 1 kWh of electricity. If the water lost to evaporation is considered this becomes about 500 gallons per kWh.

The plant generates electricity through a series of energy con-versions from the nuclear reac-tor, heat, steam and propelling the turbines. This process begins with a nuclear reactor, which initiates a continuous nuclear chain reaction. The nuclear fis-sion-taking place in the reaction generates heat, which is used to generate steam. This steam is then used to propel turbines, creating mechanical energy that is then converted to electricity. This process produces little pol-lution; it is considered a zero-emissions power source. All reac-tors need to be cooled in order to avoid an uncontrolled nuclear chain reaction. Running water through the system accomplish-es this task, which is done by removing the heat from the nu-clear reactors, which is supplied with enough water to cool the

reactors.

The Palo Verde plant has three independent electricity-producing units, and has a capacity of 3,739 MW. Annually, the plant produces 29250mWh of electricity. The ratio of this electricity generation to water use becomes 2.9 x 10 13Kwh per 20 billion gallons of treated wastewater, which equals approxi-mately 4.725 x10 8kWh/acre-feet. When viewed in terms of electrici-ty produced per gallon this is equivalent to 1450 kWh/gallon of water consumed, which makes it a very efficient use of water for gen-eration of electricity.

The Palo Verde Nuclear Gener-ating Station is a unique point of discussion concerning water use and the generation of electricity in Arizona. The plant is located 45 miles west of Phoenix, and generates power for approxi-mately 4 million people in Phoe-nix and parts of southern Califor-nia. It is landmarked as the only nuclear power generating station in the world not situated directly on a large body of water. In-stead, its cooling features are supplied using reclaimed sewage effluent from the 91st Ave wastewater treatment plant in the Phoenix area. The Palo Verde Plant uses 20 billion US gallons of treated wastewater per year. This composes about 25% of the annual overdraft of the Depart-ment of Water Resources Phoe-nix Active Management Area.

Alyssa Mazza and Maxwell Curry

Lizzie Greene and Tatum Hill

Arizona Power Service has partnered with Abengoa Solar Inc., a Spanish company, in order to construct Solana, a solar-electric generation plant in western Arizona. Once completed in 2013, Solana will be a future icon in solar generating stations all over the world. The 1,900-acre plant is currently under construction in Gila Bend, Arizona. The plant will be using Concentration Solar Power (CSP) technology and will employ thermal energy storage 2,700 para-bolic mirrors will be used to concentrate the suns energy, and transfer it into a heating fluid to raise its temperature to about 735 degrees Fahrenheit. The hot fluid will then transfer its heat energy to water and create steam. This steam will then be used to spin turbines to generate electricity. Afterwards, the heating fluid will be sent back to the solar field. Some of the water that produces the steam will be re-claimed, but most of the steam will be vented into the

atmosphere once it has been used to turn the turbines. At select times, the hot fluid will be used to heat molten salt, which will in-turn heat water to create steam even when the sun is not shining. Through this procedure the molten salt can store heat energy for up to six hours and electricity can be generated even at night.

The 280,000-kilowatt power plant will generate power for over 70,000 homes in Arizo-na. This facility will generate 600 million-kilowatt hours of electric-ity per year and will use 0.928 gallons of water for every kilo-watt-hour of electricity generat-

ed. This means Solona will con-sume a total of 1,710acre-feet of water per year, the same amount of water that 4,000 houses would consume in one year. The power plant claims it will use seventy five percent less water than the current agricul-tural use of the land. The plant will draw water from deep aqui-fers and because groundwater rights belong to the landowners, water will be readily available for the plant. The possibility of using treated wastewater is also an option that is being evaluated. Solona will also produce no greenhouse gasses and will pre-vent 350,000 tons of CO2 from being emitted into the atmos-phere every year if burning fossil fuels generated the electricity.

Solana Solar Plant

Page 4 Water /Energy Nexus Vo lume 1, I ssue 1

Payal Patel and Kelsey Hill

Water for Tucson

Water for Phoenix

Page 5 Water /Energy Nexus Vo lume 1, I ssue 1

In 1980, the Groundwater Man-agement Act (GMA) was passed to set restrictions to the amount of groundwater that could be pumped. Active Management Areas were established to man-age groundwater pumping. The Tucson Active Management Area management plan was drafted to ensure that the level of ground-water used remained in equilibri-um with its recharge to prevent Tucson becoming a “sinking city.” In earlier times, Tucson pumped freely from the ground. Another stipulation introduced by the GMA is the maintenance of an Assured Water Supply, meaning that every city in Arizo-na has to store enough water to cover the city’s needs for the next 100 years. Tucson saves groundwater by combining it

with Colorado River water brought to Tucson via the Cen-tral Arizona Project (CAP) aque-duct. Tucson is also replacing groundwater for golf courses and landscape irrigation with re-claimed water (treated sewage water effluent). Tucson is well-known for its water conservation methods.

In 2011 Tucson recharged about 123,800 AF of CAP water. Since water recharge activities started, approximately 990,000 AF of CAP were recharged by Tucson Wa-ter. The Arizona Banking Authori-ties manage CAP water in case of emergencies, such as shortages in the Colorado River or in times of canal shutdowns. In 2011, the Arizona Water Banking Authority stored 157,000 AF in storage

facilities for Tucson Water. For the first time, in 2012, Tucson Water is ordering its full allot-ment of CAP water.

Tucson Water serves about 70% of the greater Tucson area. On average, Tucsonans daily con-sume 140 gallons of water. Tuc-son annually uses about 97,700 AF of drinkable water and 15,400 AF of reclaimed water. CAP deliv-ers 1,500,000 AF total to Arizona, using 2.8 billion kWh of electrici-ty. This means about 1,900 kWh are used to pump each AF of water to Tucson. About 65% of Tucson’s drinkable water comes from the Clearwater Renewable Resource Facility, which mixes CAP water with native ground-water and pumps the blended water to consumers.

This water is treated up to a greater extent as compared to the system wide total wa-ter.

Phoenix is able to use several different resources that sur-round it in order to supply enough water to the city. The Phoenix water supply comes mainly from two different places the Salt River Project and the Central Arizo-na Project. The Salt River Pro-ject gets the majority of its water from the Salt and Verde Rivers. The Central Arizona Project gets its water from the Colorado River. It can also be noted that a small portion; less than 20,000AF of Phoenix’s supply of water comes from wells, or ground-water. The water that is in

the wells is distributed amongst the city in a complex system which requires ener-gy.

The exact amount of energy used to transport the water to Phoenix has been hard to find. What has been clarified is that the Salt River Project does not use a lot of electrici-ty to transport its water be-cause the distance from the water sources to the water plant is downhill. But, consid-erable water is loss to evapo-ration from the reservoirs on the Salt and Verde Rivers. On the other hand, the Central Arizona Project uses 1,428 kwh's to pump 1 acre foot of water from the Colorado Riv-er to Phoenix.

The amount of water the city of Phoenix is using has start-ed to decrease over the years. In 2003 single family residential use was 143 gal-lons per day per family, sys-tem wide-potable was 197gallons, and system-wide total was 217gallons. By 2008 water use started to decrease where the single family resi-dential water use was 123 gallons, system wide-potable was 173gallons, and the sys-tem-wide total was 184 gal-lons. It can be noted that the system-wide total water fig-ure is the total amount of drinking water in the city, while system wide potable water is the amount of water treated up to a certain de-gree and can be used for eve-ry single purpose in a city.

Energy for Water Energy for Water

Lois Fozzard and Brenda Perez

Alexa Wollach and Malcolm Daruwalla

Assignment: Students in the LASC 195a-002 Water Resources

in the Tucson Basin class offered in Spring 2012, conducted re-

search on the Water/Energy Nexus for Arizona. The information

contained should not be referenced without verifying the accuracy or

sources of the information. For more information contact:

jjriley@ag.arizona.edu Class Web site:

cals.arizona.edu/swes/tucwater2

Energy/Water Nexus Relationships

Water Resources in the Tucson Basin

LASC 195a-002 Spring 2012

Water for Energy (water used in the generation of electricity)

Electricity for Tucson: 0.75 gal/kWh

Electricity for Phoenix: 0.96 gal/kWh

Navajo Generating Plant: 0.5 gal/kWh

Hoover Dam: 500 gal/kWh

Palo Verde Nuclear Plant 1,450 kWh/gallon of water consumed

Solano Solar Energy Plant: 0.928 gal/kWh

Energy for Water (energy used in the delivery of water)

Water for Tucson: 1900 kWh/AF

Water for Phoenix: 1428 kWh/AF

Water/Energy Nexus Vo lume 1, I ssue 1 Page 6

REFERENCES

Water for Energy

Electricity for Tucson

Interview with Reland Kane at Tucson Electric Company via e-mail

Tucson Electric Company website : www.tep.com

Electricity for Phoenix

Salt River Project http://www.srpnet.com/water.aspx

Arizona Public Service http://www.aps.com/

Earth Island Journal http://www.earthisland.org/journal/index.php/eij/article/mirage/

Navajo Generating Plant

Cronkite News Online

http://cronkitenewsonline.com/2012/01/northern-arizona-power-plant-among-nations-biggest-greenhouse-gas-

producers/

Southwest Hydrology

http://www.swhydro.arizona.edu/archive/V6_N5/SWHVol6Issue5.pdf

Wikipedia

http://en.wikipedia.org/wiki/Navajo_Generating_Station

Power Generation

http://powergen.wordpress.com/2008/06/16/navajo-generating-station-navajo-reservation-page-arizona/

Continued on next page

Volume 1, I ssue 1 Water /Energy Nexus Page 7

Hoover Dam

Enviro- News and Politics http://www.enviro-news.com/article/hoover_dam_nevada.html

Hydroelectric Advantages http://hydroelectricityadvantages.com/

Energy resources: Hydroelectric Power http://www.darvill.clara.net/altenerg/hydro.htm

History Channel http://www.history.com/topics/hoover-dam

Sunset Cities http://www.sunsetcities.com/hoover-dam/faqs-00.html

Nevada http://travelnevada.com/destinations/hoover-dam/

Recreation.gov http://www.recreation.gov/recAreaDetails.do?contractCode=NRSO&recAreaId=29&contractCode=129

U.S. Department of the Interior- Lower Basin Region http://www.usbr.gov/lc/

Palo Verde Nuclear Plant

Hedding, Judy. "Palo Verde Nuclear Generation Station." About.com Phoenix. Web. 29 Mar. 2012. <http://phoenix.about.com/cs/

utilities/a/paloverde.htm>.

Nevarez, Griselda. "Officials: Largest Nuclear Power Plant in U.S. Equipped for Emergencies." TucsonSentinel.com. Tucson Senti-

nel, 30 Mar. 2011. Web. 22 Mar. 2012. <http://www.tucsonsentinel.com/local/report/033011_palo_verde_nuclear/officials-

largest-nuclear-power-plant-us-equipped-emergencies/>.

"Palo Verde Nuclear Power Plant." Wikipedia. Wikimedia Foundation, 17 Mar. 2012. Web. 01 Mar. 2012. <http://

en.wikipedia.org/wiki/Palo_Verde_Nuclear_Power_Plant>.

"Arizona Nuclear profile." eia.gov. N.p., n.d. Web. 29 Mar 2012. http://www.eia.gov/cneaf/nuclear/state_profiles/arizona/az.html

Plant

Solano Solar Plant

"Abengoa Solar :: Our Plants :: Plants under Construction :: United States." Abengoa Solar. Abengoasolar, 2011. Web. 09

Apr. 2012. <http://www.abengoasolar.com/corp/web/en/nuestras_plantas/plantas_en_construccion/estados_unidos/>.

"APS :: About Solana - Arizona's Largest Solar Power Plant." APS. APS. Web. 09 Apr. 2012.

<http://www.aps.com/main/green/Solana/About.html>.

Basantani, Mahesh. "World’s Largest Solar Power Plant Coming to Arizona in 2011 Read More: World’s Largest Solar Power

Plant Coming to Arizona in 2011 | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building." Inhabitat. Inhabi-

tat, 25 Feb. 2008. Web. 01 Apr. 2012. <http://inhabitat.com/world%E2%80%99s-largest-solar-power-plant-coming-to-arizona-in-

2011/>.

McKinnon, Shaun. "Amid State's Push for Solar Power, Water-supply Worries Arise."Arizona Local News. The Arizona Re-

public, 17 Jan. 2010. Web. 09 Apr. 2012. <http://www.azcentral.com/arizonarepublic/news/articles/2010/01/17/20100117water-

solar0117.html>.

Seminar, Brown Bag. "Solar Energy and Water Use in Arizona." Ag.arizona.edu. Ag.arizona, 01 Apr. 2012. Web. 16 Sept. 2010.

<http://ag.arizona.edu/azwater/programs/brownbag/Barnhart.pdf>.

"Solana Generating Station Gila Bend, Arizona." Energy. Energydeals Wordpress, 2 June 2010. Web. 09 Apr. 2012. <http://

energydeals.wordpress.com/2010/06/02/about-solana-generating-station/>.

Volume 1, I ssue 1 Water /Energy Nexus Page 8

Energy for Water

Water for Tucson

CentralCentral Arizona Project FAQ. < http://www.cap-az.com/aboutus/faq.aspx>.

2011 Monthly Delivery Report. < http://www.cap-az.com/Portals/1/Documents/2011-12/2011%20MONTHLY%

20DELIVERY%20REP.pdf>.

Navajo Generating Station. < http://www.cap-az.com/publicinformation/navajogeneratingstation.aspx>.

About Tucson Water. < http://cms3.tucsonaz.gov/water/about-us>.

Water for Phoenix

Arizona Water Meter: A Comparison of Water Conservation Programs in 15 Arizona Communities-http://

www.westernresourceadvocates.org/azmeter/phoenixsumm.pdf

Salt River Project-http://en.wikipedia.org/wiki/Salt_River_Project

Water Supply Question and Answers-http://phoenix.gov/WATER/drtfaq.html

Water in the Desert- Phoenix water supply-http://phoenixwaterfronttalk.com/2009/06/22/water-in-the-desert-phoenix-

water-supply/

Water/Energy Nexus

Volume 1, I ssue 1 Water /Energy Nexus Page 9