About the project

  • What is the Big Chino Valley Pumped Storage Project?

    The proposed Big Chino Valley Pumped Storage Project proposed by ITC Holdings Corp. (ITC) will serve as an integrated solution to modernize the Southwest’s energy infrastructure. This includes updating the region’s power grid to meet an evolving, uncertain energy future – a grid with the flexibility to accommodate diverse generation resources, changing market demands, increased challenges to forecasting of electricity supply and demand and ever evolving technology inputs.


    The project involves a large-scale, closed-loop pumped storage hydroelectric facility, one powerhouse and two reservoirs covering 420 surface acres located in Yavapai County, Arizona. It also includes three connecting transmission lines. ITC has identified three preferred micro corridors and associated alternative segments for additional study and stakeholder review.


    Eldorado Corridor: A 500 kV, approximately 145-mile line that connects to the existing Eldorado Substation


    Peacock Corridor: A 500 kV, approximately 20-mile line that travels west to interconnect with the existing the Peacock Substation


    Yavapai Corridor: A 500 kV, approximately 50-mile line that travels east to interconnect with the existing Yavapai Station


  • Why is the project needed?

    Southwest states are moving to renewable energy to supplement other forms of energy generation and to meet ambitious energy goals. This changing energy mix is creating concerns over future energy supply and electric grid reliability in a region already experiencing rapid population growth, increasing energy demands and constrained interstate transmission lines. To support this evolving, uncertain energy future, a modernized grid is needed accommodate growing market demand, diverse generation resources, increased challenges in electricity supply and demand forecasting and ever evolving technology inputs.

  • How will it work?

    This facility will pump water from a lower reservoir to an upper reservoir during periods of high generation and/or low electrical demand (excess electricity created) and store it as potential energy, like a large electric battery. The facility can return the stored energy to the grid on demand by flowing water by gravity through a generation turbine back to the lower reservoir. Acting like a large electric battery, the facility will help address bulk storage of excess renewable energy, offer reliability support to the electrical grid and redeploy the excess renewable energy when and where it’s needed across the proposed transmission interconnections.

  • What is the proposed location?

    This pumped storage facility is proposed for Arizona’s Yavapai County, centered about five miles southeast of Seligman, Arizona with three transmission lines connecting to existing substations in Arizona and Nevada.

  • Why was the proposed site selected?

    This site has suitable topography required for a pumped storage facility. It provides the required difference in elevation between the two reservoirs within a reasonable distance, which allows the powerhouse’s pump/turbine generators to operate efficiently in both pump and generation modes. It was also selected due to its proximity to available grid connections and electricity market hubs.

  • What is the project schedule?

    The Federal Energy Regulatory Commission (FERC) approved ITC’s request to prepare the project’s licensing application with the Traditional Licensing Process in March 2018. In consultation with stakeholders, ITC is now in the process of designing and conducting studies, preparing environmental analyses and developing a licensing application with a goal to file the application with FERC in early 2020. ITC has a goal for commercial operation in the 2025-2028 period.

About the water

  • How much water will be needed to develop the reservoirs?

    The project will require an estimated one-time fill of approximately 27,000 acre-feet or about 8.7 billion gallons (one acre-foot is equivalent to 325,851 gallons of water). Approximately 6,000-7,000 acre-feet will be used for construction with slightly more than 20,000 acre-feet used for the pumped storage facility operation.

  • What is the current usage of water out of the Big Chino Aquifer on an annual basis from the area?

    Recent agricultural use (i.e., net use or pumped-transpired and evaporated) has been about 3,000-4,000 acre-feet per year or approximately 980 million - 1.3 billion gallons. Additional municipal, industrial, stock and domestic use has not been recently updated.

  • What is the impact on the proposed groundwater withdrawal?

    ITC is undertaking an evaluation of the potential impacts of its proposed groundwater withdrawal to the Big Chino Aquifer and the Verde River. This evaluation involves modifying, updating and improving the U.S. Geological Survey’s Northern Arizona Regional Groundwater Flow Model with input from key stakeholders including representatives from state and federal agencies, local municipalities, tribal representatives and local and national environmental groups.


    Through hydrological modeling and evaluations underway, ITC’s goal is to produce a conservative estimate of the project’s effects on the aquifer system. Where assumptions are made, we will overestimate the project’s effects and underestimate the effects of mitigation. By using conservative estimates, ITC can avoid adverse impacts to water resources.


    ITC is working with the water work group and other stakeholders to identify potential short-term and long-term strategies to offset potential impacts based on sound science – all with the goal of maintaining long-term stewardship of the water and land resources. If studies identify adverse impacts to the Big Chino Aquifer and/or Verde River, we are committed to undertaking mitigation efforts to address impacts on the Big Chino Aquifer, Verde River and residential wells. Additionally, we will not impede upon appropriated water rights.


  • What does mitigation mean?

    Mitigation means identification and implementation of measures through sound science to avoid any adverse short-term or long-term impacts that could result from the construction and operation of the project, including the groundwater withdrawal for the initial fill.

Proposed transmission micro corridors

  • What is a transmission micro corridor?

    A micro corridor is a produce of an extensive evaluation of different options generated through a Geographic Information System (GIS) analysis. Each of the project’s micro corridors is approximately 1,000 feet wide. The micro corridors, including the alternative segments, represent the transmission line study areas that will undergo further engineering analysis and environmental review with stakeholder and public consultation.

  • How were the three interconnection points chosen for this project?

    The project’s interconnection points were chosen through an extensive analysis of the current electric system in the Southwest region including Arizona and Nevada. The interconnection points coordinate with existing high-voltage transmission within the region and ensure the project is fully utilized to serve all of its customers. The interconnection points also enable the project to maximize its ability to enhance the reliability of the existing electric grid.

  • How were the micro corridors evaluated for this project?

    The micro corridors were evaluated based on three categories: engineering, natural and built environments. Our engineering evaluation focuses on existing infrastructure in the area like roads, pipelines, railroads, etc. and areas of constructability like avoiding steep slopes. Natural evaluation focuses on types of land use including pasture/rangeland, forests and crop production areas as well as critical habitat, endangered species, streams and wetlands. Our final criterion covers the built environment, which considers things like development in the region, existing land use and historic structures, etc.


    After entering this data into a GIS model, a composite micro corridor was developed using all three criteria. A group of experts, including engineers, archeologists, biologist, and construction experts then reviewed the data and developed the micro corridors for further study.


  • What will happen with the micro corridors now?

    Engineers, archeologists, biologists, and construction experts will visually review each of the micro corridors to assess potential project impacts and associated mitigation measures. Based on this review, as well as landowner, stakeholder and public input, a center line for the new transmission lines will be determined within the micro corridors.


    After determining the center line, engineers will provide a draft of pole locations for further study with access roads, constructability and impacts to the resources. The analysis of the project’s transmission routes will be included in the license application to be submitted by ITC to FERC in early 2020.


  • What is the voltage of the lines?

    The transmission lines will be energized at 500 kV.

  • What will the transmission towers look like?

    At this time, we do not know what the final towers will look like and there may be more than one type. The final design of the transmission towers is dependent on terrain, engineering requirements, and agency input.

  • How wide will the final right of way be for this project?

    The right of way will have varying widths depending on terrain, access, structure types, etc. Typically, right of way widths for these types of transmission lines are in the 150-250 feet range. Access to and from the structures will also need to be determined.

  • What is the estimated pole heights for the transmission lines?

    Pole heights will vary depending on structure type and terrain. Typically, the poles will vary from 120 to 190 feet.

  • What is the span length for the transmission lines?

    Span lengths will vary depending on structure type, terrain, special crossings, etc. Typically, the span lengths proposed for this project are 900 to 1,500 feet.

  • Will the transmission lines affect radio or television reception?

    No, the lines will not affect radio or television reception. The lines are also designed to limit audible noise in and around the right of way.

  • Will the lines affect GPS signals or accuracy?

    No, GPS signals are transmitted at a higher frequency than the transmission lines. With the higher frequency for the signals and multiple satellites used there is no signal degradation for GPS receivers.

  • What is ITC's approach to identifying final transmission routes?

    ITC’s approach to transmission line development takes into consideration the unique nature of every project. We will assess each micro corridor individually for safety, reliability, cost-effectiveness, environmental impacts, and community impacts to determine the best transmission solution.


    We recognize the critical role that local residents, landowners and communities play in reviewing and hosting new electric transmission lines. We are committed to open, honest and frequent communications and will work respectfully with stakeholders throughout the final design to identify the transmission line routes that will minimize impacts to landowners and the environment while meeting the project’s requirements.

Project benefits

Pumped hydro storage is a common, proven technology used worldwide to support grid transmission and energy storage. The proposed project offers several benefits:

  • Increases reliability of the electrical grid and regional generation
  • Closed-loop design limits water consumption for initial and ongoing water usage
  • Reduces transmission congestion
  • Fast ramping capabilities and reduced over-generation risk
  • Frequency regulation and improved voltage stability
  • Firming of renewable resources
  • Reduced resource cycling and renewable curtailment
  • Resolves the largest Western Electricity Coordinating Council (WECC) contingency in creating a diverse outlet for the Eldorado-Moenkopi transmission line
  • Presents a near 1-to-1 replacement of any temporary loss of energy capacity from Palo Verde Nuclear Station near Phoenix (e.g. unit trip)
  • Ancillary support for the operational characteristics of the Southwest transmission grid as the region responds to the increased penetration of renewable resources

  • How will the project benefit me and my community?

    The project would significantly increase the tax base for the County, which would help the County pay for infrastructure and other investments. The project also would have significant positive impact on the local and regional economy. A preliminary Arizona State University study estimates the project may generate $2.7 billion to GDP in Yavapai, Coconino and Mohave Counties – along with 31,215 job years of employment. The study also estimates the project will generate an additional $5.1 billion to the statewide GDP and 45,871 additional job years of employment over a 25-year period statewide. A job year is equivalent to one annual full-time position. In addition, ITC supports numerous community initiatives in the communities in which it does business.

  • To what extent will this project provide energy storage services to California and Nevada rather than to Arizona?

    ITC is in discussions with Arizona utilities regarding the benefits of the project. All electricity stored and released by the project could potentially be contracted to Arizona utilities.


    Currently, Arizona’s demand (load) is approximately 20,000 MW, and the project could provide 2,000 MW of storage. ITC believes that 10 percent is an appropriate amount of storage versus overall demand and will help incorporate public policy requirements for renewable generation resources.


    Given the amount of change and future uncertainties in the broader electric system, this project will provide an additional tool to help manage the unknowns. ITC will not discriminate against interested parties of the project; however, any non-Arizona participation will benefit Arizonans through a variety of benefits including – but not limited to – tax contribution, jobs, and contribution toward project costs.


stakeholder communications

  • Will ITC communicate with stakeholders directly regarding the licensing process?

    Stakeholder engagement and public involvement are critical to the development of the proposed Big Chino Valley Pumped Storage Project. In addition to engaging all relevant agencies to comply with FERC’s Traditional Licensing Process requirements, ITC is also engaging stakeholders through one-on-one meetings, small group presentations, and joint stakeholder public meetings as part of its commitment to transparency and developing a project that benefits the region.

  • Has ITC had discussions with various Indian Tribes?

    ITC continues to engage in outreach to, and plans to consult with, affected Indian Tribes. In addition to traditional outreach, ITC is also engaging Indian Tribes under Section 106 of the National Historic Preservation Act to discuss study plans, cultural resources, potential impacts and mitigation measures.

  • How can I learn about the project and stay informed?

    Here are several ways to get involved or to stay informed:
    Sign up to receive emails about upcoming meetings and updates
    View our upcoming meetings and attend a meeting and read information from past meeting events
    Contact us to request a meeting for your community group or organization

    The Big Chino Valley Pumped Storage Project must be licensed by the Federal Energy Regulatory Commission (FERC). ITC encourages interested stakeholders to attend the public meeting to learn more about the licensing process and share their input regarding the resource studies that will inform the license application that ITC will submit to FERC.


Proposal calls for 2,000-MW pumped storage facility in Arizona

Oct 26, 2017

A proposal filed at the Federal Energy Regulatory Commission by a subsidiary of transmission company ITC Holdings Corporation calls for the construction of a 2,000-megawatt, closed-loop, pumped storage hydroelectric facility in Arizona. The project is intended to boost reliability and facilitate the integration of renewable energy in the southwestern part of the U.S. Read More.