Projects background
SRP has an obligation to ensure a reliable and affordable source of electricity for residential, business and industrial customers. To meet the growing needs of SRP's customers, we are planning new generation resources.
SRP has identified the need for 2,500 megawatts (MW) of new summer peaking and intermediate generation to meet electricity demands through 2022. We are evaluating a number of options to meet this need and will most likely adopt a multi-faceted approach.
The first step was SRP's power purchase agreement for the output of the TransCanada project near Coolidge, which will meet approximately 500 MW of the 2,500 MW summer need.
The next steps will be to purchase additional output from others and/or build new generation at new or existing SRP sites, as may be determined through SRP's evaluative process.
Selected sites for generating facilities
SRP has selected two sites in Pinal County, as depicted in the map below:
- The "Abel" site is near the SRP Abel Substation in Florence
- The "Pinal Central" site is near the Pinal Central Substation south of Coolidge.
A third site was considered, near Eloy. While the Eloy site is a good one, SRP decided to proceed with Pinal Central and Abel based upon economic criteria and public acceptance of the Abel and Pinal Central sites. A third site near Eloy could be pursued at a later time.
How SRP selected the sites
SRP selected the sites though a comprehensive siting study. The proposed sites offer the necessary access to transmission lines and natural gas resources, and generally meet the siting criteria of the study.
The sites identified for possible power plant development are near the communities of Florence, the Gila River Indian Community, the SanTan Valley, Coolidge, Casa Grande and Eloy.
The proposed sites are located in industrial planning areas. SRP anticipates between 160 and 200 acres of land will be adequate to address the needs of each of the projects.
The electricity produced by any SRP generation is used to meet our customers' electricity needs, including our customers in Pinal County.
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About the facilities
The Abel site will be developed to come online in stages between 2015 and 2017. SRP plans to construct a simple-cycle peaking plant consisting of eight to nine natural-gas-fueled generating turbines of up to approximately 850 megawatts (MW). In addition to the turbines, the plant sites will have limited fuel storage tanks, water treatment equipment, water storage facilities and a plant control building.
The Pinal Central site will be developed at a time, to be determined by resource need by 2018. It is expected to be a combined-cycle, natural-gas-fueled plant of up to approximately 1150MW.
Find out about the environmental considerations.
Natural gas
The El Paso and/or Transwestern pipeline systems will supply natural gas to the Pinal locations. It will be necessary to build a short connecting line from the main pipelines to each of the locations.
The planned projects will not negatively affect natural gas supplies in the area.
Plant appearance
Generally speaking, residents would see a new industrial facility with buildings, stacks and electrical facilities. Examples of facilities that use similar technologies are APS's Sundance Plant east of Coolidge and SRP's Desert Basin Plant in Casa Grande.
Natural gas power plants are generally smaller, cleaner and less obtrusive than older coal-fired plants. Design details will be shared with the public when they are developed.
Lighting at the plant
All lighting for the facilities will be designed with our neighbors in mind. At urban plants, SRP installs manual switching on outside lighting so that plant staff can switch on those lights only when work in specific areas is necessary.
Plant noise
SRP realizes that some noise is associated with the construction of new plants and will take steps to minimize the effects on the surrounding community. Construction hours are limited to the terms of noise ordinance for the respective communities.
SRP has plants in communities now and receives very few inquiries regarding noise. During special circumstances, such as concrete pours - which must be done continuously until complete - construction will be required around-the-clock. Be assured that SRP will work to inform our neighbors of activity throughout any construction. The SRP staff works diligently to keep special activities to a minimum and will design the normal plant operations to minimize impact on the local community.
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Traffic impact
There will be an increase in site activity during the construction phase of the project. However, the normal operation of the facility will not result in a significant increase in traffic. While the increase during construction will be short-term, a mitigation plan will be developed prior to construction activities.
Safety and security implications
SRP has an extensive safety program for its employees and facilities. Safety is a corporate initiative against which SRP's success is continually measured.
Plant personnel are highly skilled professionals who are trained in all aspects of plant safety. The generating technology at the plants may require chemicals - such as sodium hypochlorite, sulfuric acid and aqueous ammonia. The first two are used for water treatment; ammonia is used with the air quality control equipment. The storage, use and disposal of all chemicals will comply with all applicable environmental and health regulations. No chemicals will be disposed of on site.
As with all SRP facilities, lighting, fencing and other security measures will be factored in to the overall facility design to keep the facility secure and safe for the community.
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Meeting peak load
Meeting "peak" load means that facilities generate power during times of high or peak demand. For SRP, this typically means the afternoons of the hottest summer days. One of the most effective ways of meeting peak load is through simple-cycle peaking plants.
In the simple-cycle process, natural gas is converted into electricity by burning gas to create heat to drive turbine rotors connected to an electrical generator. Simple cycle units have the advantage of versatility, as they can be brought on line in as little as 10 minutes. Peaking facilities are expected to operate less than 50% of the time during the year. An example of a peaking facility is the APS-owned Sundance Power Plant near Coolidge.
Meeting intermediate load
Intermediate load includes the peak periods, but also includes "shoulder" times, where electricity use is significant, but less than the peaks.
One way of providing generation for intermediate loads is through "combined-cycle" natural-gas units. These units produce power in two cycles. The first is through a turbine fueled by natural gas. The second is through another turbine fueled by steam produced by the waste heat of the gas turbine. A combined cycle unit has the advantage of producing power with greater efficiency, but has the disadvantage of longer start up times.
Intermediate facilities are expected to operate approximately 75% of the time. An example of a combined cycle unit is the Desert Basin Generating Station in Casa Grande.
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Permitting process and construction schedule
Prior to construction, each project will complete the process to receive a Certification of Environmental Compatibility that must be approved by the Arizona Power Plant and Transmission Line Siting Committee and the Arizona Corporation Commission.
Multiple environmental requirements apply to the construction and operation of such a facility. Two significant permits are the air quality permit and the Aquifer Protection Permit. The air quality permit is issued by the Pinal County Air Quality Department, and the Aquifer Protection Permit is issued by the Arizona Department of Environmental Quality. There are public comment periods in both instances.
The Abel site will be developed as an approximately 850MW simple-cycle peaking plant consisting of eight to nine natural-gas-fired turbines. The plant will be constructed in phases, to match load growth as the economy recovers. Initial capacity will be operational in 2015 and additional capacity will be added as needed, with the full plant operational by 2017.
The Pinal Central site will be developed as determined by resource need.
System benefits
There are two benefits to these sites. The first is that they are either in or close to the southeast portion of SRP's load center. The proximity to SRP customers utilitizes recently-sited transmission lines and substations.
The second is that the electric system needs some generation that is local to the load to provide necessary voltage support. Each of these sites provides some voltage support. The Abel site is particularly valuable in this regard, as it is located within the SRP load center.
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