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Fossil Fuels

Natural Gas

The grounds of natural gas fueled Ocotillo Power Plant in Tempe are also the location of the APS Solar Technology and Research (STAR) Center, which researches solar generation.

Three quarters of Arizona’s natural gas supply is used to create electric power. Several natural gas pipelines import the resource from Texas and California. Although almost two-fifths of the households in the state rely on natural gas for heating, the mild winters help keep overall household consumption of natural gas relatively low.

Arizona relies on interstate and international importation of natural gas, and is part of the transportation corridor for shipping gas from production areas in Texas and the Rocky Mountains to the southern California region via several major natural gas pipelines. In May, 2011, a natural gas fueled power plant opened in Coolidge. The plant, built and owned by TransCanada Corporation, will generate supplemental power for the Salt River Project (SRP) during peak times like hot summer days, cold winter mornings, and when renewable energy sources do not produce enough power to meet demand.


Cholla Power Plant near Holbrook is exploring carbon sequestration to reduce its emissions.

Coal-fired plants supply almost two-fifths of Arizona’s electricity. Arizona produces approximately 7.5 million tons of coal every year. Coal mining operations by Peabody Coal take place on the Navajo Nation at Black Mesa on the Colorado Plateau. More than one-third of the coal produced in Arizona is delivered to coal-fired generators in Nevada. The remaining two-thirds, supplemented by coal supplies arriving from New Mexico, feed coal-powered electricity generators in the state. The controversial Navajo Generating Station located in the Navajo Nation near Page is the largest coal-fired power plant in the West.

How does coal m​ake e​lectricity?

Tour a power plant! The SRP's virtual power plant tour shows you how electricity is generated at a coal generated power plant using panoramas and animations.

Information from Energy Information Administration

Potential Storage for Carbon Emissions

Can Arizona trap carbon emissions in saltwater? The WESTCARB Arizona Pilot project recently assessed the feasibility of storing carbon dioxide emissions from the coal-fired Cholla Power Generating Station in deep-lying porous rock formations filled with saltwater near Holbrook. This practice, called carbon sequestration, is a form of geoengineering simulating natural geochemical cycling of carbon between the atmosphere and reservoirs.

To determine whether the site could hold carbon dioxide, the WESTCARB team used computer models to predict the distribution and immobilization of injected carbon dioxide and its effects on the subsurface. Next, the team drilled a well to collect rock and fluid samples. The findings at that location showed very salty water (high salinity) and good caprock “seals,” both necessary for this type of carbon dioxide storage. However, the rocks were not permeable enough to capture sufficient amounts of carbon dioxide and the location was ultimately not suitable for carbon sequestration. Geologists intend to explore additional locations in northeast Arizona.

Information from WESTCARB.


Arizona's Total Energy Consumption in 2010

Information from the Energy Information Administration

Arizona expends most of the largest percent of its total energy use on transportation. Almost 100 percent of this type of energy consumption comes from petroleum. Oil production in Arizona is small scale in contrast to that of New Mexico or Texas, but exploration for petroleum continues in Southern Arizona. Arizona imports much of its crude oil resources from other states. Petroleum product is delivered from refineries via two pipelines, one from southern California and the other from El Paso, Texas.

Arizona is also a leader in the creation of biofuels, with programs at our state universities leading the charge to produce biofuel from algae—some of it grown in geothermally warmed pools. Read more about Arizona’s extensive biofuel development.

Hydrog​en Fuel Cell Plant Creates Low-Emission Electricity from Natural Gas

The Arizona State University Polytechnic campus is home to Arizona's first demonstration of a commercial-scale fuel cell power system. Arizona’s First Hydrogen Fuel Cell Plant is one of only 35 plants of this kind in the world!

Fuel cells convert the chemical energy from fuel with a chain reaction that uses oxygen. In this case, a Molten Carbonate Fuel Cell System extracts hydrogen from natural gas to use as fuel. This operation extracts hydrogen from natural gas and uses the hydrogen to produce low-emission electricity.

One substantial benefit to this method is that the electricity it creates can be stored. Often, electricity that is created must be used or it will be lost. The small physical space required by this operation means a fuel cell plant can be relatively mobile. Hydrogen burned with oxygen produces heat and water. A third and incredible benefit is that the plant’s by-product, water, can be used for water heaters and air conditioning units.

The plant produces about 250 kilowatts of electricity, enough to power about 100 homes. It is connected to SRP’s power grid, and has generated about 2.5 million kilowatt hours of electricity since its opening in 2005.

What is a Molten Carbonate Fuel Cell?

A fuel cell consists of two electrodes sandwiched around an electrolyte. Molten Carbonate fuel cells (MCFC) use high-temperature compounds of salt (like sodium or magnesium) carbonates (chemically, CO3) as the electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat. It will produce electricity as long as fuel is supplied.

Information from SRP Commercial Fuel Cell Fact Sheet (PDF).