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We strive to reduce or eliminate emissions of environmentally harmful substances such as:
- Greenhouse gases (GHG)
- Ozone depleting substances (ODSs) as defined by the Montreal Protocol
- Key air pollutants including carbon monoxide, lead, volatile organic compounds, nitrogen oxides (NOx), particulate matter (PM-10) and sulfur oxides (SOx)
We maintain air emissions per megawatt-hour at or below industry averages. We achieve this record by a combination of nuclear power, emissions control technology, improved power plant efficiency and a cleaner fuel mix.
All of our power plants are required by law to limit their emissions and operate within parameters set by federal, state and/or local environmental agencies. In addition, all major stationary sources of air pollution (including power plants) are required under Title V of the 1990 Clean Air Act Amendments to obtain air quality operating permits. All our plants maintain the requisite air permits and we update our permits as required. We added baghouses at the Cholla Power Plant on coal-handling facilities in 2002. 
Our Management Plan for ozone-depleting substances requires tracking the use and maintenance of equipment containing chlorofluorocarbons (CFCs) and CFC-based refrigerants. The plan provides for proper maintenance and service of CFC-containing equipment to prevent CFC releases to the environment. Our policy is to replace old or obsolete CFC containing equipment with non-CFC chemicals as our operations allow.
Climate Change
APS is one of the first electric utilities to sign the Climate Challenge Participation Accord to reduce greenhouse gas emissions to 1990 levels in 2000. Given our higher than normal population and load growth in the Southwest, we acquired additional carbon dioxide (CO2) credits from Niagara Mohawk Power Corporation (NMPC) to ensure we could meet our year 2000 commitment. In exchange for the CO2 credits, we gave NMPC sulfur dioxide (SO2) credits. NMPC subsequently "retired" the SO2 allowances, donating them to environmental organizations. APS met its year 2000 commitment.
The APS service territory has experienced tremendous growth over the past decade as illustrated in APS Historic/Projected C02 Emissions graph. Meeting this growth and its associated electricity demand has required APS to augment its existing energy generation capacity. This demand has been met by more efficient use of existing sources, such as the up-rating of the Palo Verde Nuclear Generating Station, improving the availability of existing fossil plants and the addition of state-of-the-art gas-fired generators. Over time, the net effect of this demand has been an increase in the overall company CO2 emissions, but with a corresponding reduction in CO2 intensity in (lbs/MWH). Note that this trend is projected to continue through 2012. Pinnacle West's strategy is to provide a diverse mix of energy sources to ensure a reliable and stable cost of energy to its customers while meeting their growing demand. In addition, APS is actively involved in several leading-edge technologies and conducting research into other potential energy options in the future.
Greenhouse Gas-Reducing Projects
Solar
With more than 300 sunny days a year, Arizona has an abundant solar resource. For more than 30 years, APS has been a leader in solar energy and research. APS operates several solar plants across the state, with a total installed capacity of 2.35 megawatts. Use of our current solar plants avoided the emission of more than 800 tons of greenhouse gas in 2002.
In 2002, APS began operating the first phase of its Prescott Airport Solar Power Plant. Located about 100 miles north of Phoenix, this facility is expected to eventually put five megawatts of capacity on the APS grid, making it one of the largest solar photovoltaic power plant in the world.
Ash Sales
Coal combustion fly ash is a powdery material that is a byproduct of burning coal at electric utility plants. U.S. power plants produce millions of tons of coal fly ash annually. APS is using its fly ash to help reduce greenhouse gases while adding to its bottom line. APS sells much of its fly ash for use in concrete production. This offsets energy used for cement production and results in reduced greenhouse gas emissions. The company sells bottom ash and cenospheres in addition to fly ash.
Here are the number of tons of CO2 reduced through ash sales in 2002:
Fly ash
Total sales = 328,952 Tons of CO2 reduced
APS Share = 114,825 Tons CO2 reduced
Bottom Ash
Total = 1,079 Tons of CO2 reduced
APS Share = 763 Tons of CO2 reduced
Cenospheres
Total = 341,440 Tons CO2 reduced
APS Share = 341,440 Tons of CO2 reduced
New fuels
New fuels
In 2002, APS opened its hydrogen/compressed natural gas fueling station at one of its downtown facilities. The fueling station has been configured to supply hydrogen, compressed natural gas or combination of the two to vehicles capable of operating on such fuels.
This station will enable APS to gain experience handling these fuels on a small scale, before seeking larger applications. In the meantime, company vehicles that use hydrogen have a place to refuel, and they emit nothing but water vapor from the exhaust.
Biomass
APS is involved in a biomass project in northeastern Arizona that, while reducing greenhouse gas emissions, will help reduce future forest fire threats by converting the trees and other vegetation removed during forest thinning into electricity. This technology converts vegetation waste such as forest and agricultural byproducts and even yard trimmings into clean fuel to power generators. By using the wood chips that are produced from forested trees, APS expects to reduce greenhouse gas emissions by 15,000 tons per year.
Other projects
- Trip reduction: Company employees voluntarily telecommute, carpool and use other means to arrive to and from work. In 2001, more than 8,000 tons of greenhouse gas was reduced through these means.
- Algae: APS is supporting efforts to grow algae in ponds, which is fed with an enriched source of carbon dioxide emitted from APS’ plants. The algae is grown in ponds, then is used as a nutrient for plants as well as other applications.
- Off-grid solar: Customers who live off the grid use APS-maintained solar energy as their primary energy source. In 2002, this resulted in more than 800 tons of greenhouse gas reduction.
To achieve additional CO2 reductions, APS joined 25 other electric utilities in the PowerTree Carbon Company, which plants trees in ecologically sensitive areas of the lower Mississippi Valley in cooperation with local and national environmental and conservation organization.
Changes to APS’ generation mix have also reduced the intensity of CO2 emissions measured in pounds per megawatt hour. From 1999 to 2001, APS reduced CO2/MWh by more than 12.7 percent. Based on energy demand and dispatch projections, this intensity will continue to decline. Through 2012, cumulative reductions of more than 24 percent are expected.
The addition of natural gas capacity and the continual improvements at the Palo Verde Nuclear Power Plant have been key to these reductions. Each year since 1990, Palo Verde had avoided more than 20 million tons of CO2 emissions annually (more than six million tons of that attributed to APS ownership share of Palo Verde) and improvements have raised this amount to nearly 30 million tons per year since 1997.
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