Duke-American Transmission Co.

We bring together the strengths of two leading electric industry companies to build, own and operate new electric transmission facilities throughout North America.


ApplicantThe sponsor of an electric transmission line project subject to NEPA review. On the Zephyr Power Transmission Project, the applicant is Zephyr Power Transmission Company LLC.
CenterlineA line on a map or flagged on the ground that indicates the location of a linear feature such as a road or a transmission line. The linear feature is further defined by its total width (right-of-way), either for construction or operation, which is bisected into two parts, usually equal, by the centerline.
CapacityRefers to the amount of power a transmission facility (line, transformer, etc.) can reliably deliver. Capacity is measured in megawatts and is limited by the current (in amperes) that the facility can carry or the minimum voltage levels present at a substation (under either steady-state or outage conditions).
CircuitAn electrical device that provides a path for electrical current to flow, or along which an electrical current can be carried. In the case of high-voltage transmission, a set of wires energized at transmission voltages extending beyond a substation which has its own protection zone and set of breakers for isolation.
Constraint (routing)A resource or topographic geological characteristic that potentially limits transmission line routes, including areas that are closed by regulations (e.g., municipal airports, wilderness area) or where impacts would be very difficult or impossible to mitigate due to resource protection and other legal requirements (e.g., many inventoried roadless areas).
Converter stationFor the Zephyr Power Transmission Project, the facility in Wyoming that converts alternating current (AC) power collected from the wind turbines into direct current (DC) power for transmission, then converts DC power back to AC power for insertion into the local electricity grid at the delivery point.
Cooperating agencyA federal, state or local governmental entity or tribe that has accepted an invitation from the lead federal agency to participate in the NEPA (see definition of NEPA below) process. The invitation is generally formal and accompanied by the signing of a Memorandum of Understanding. Typically, a cooperating agency has jurisdiction by law or special expertise with respect to any environmental issue which will be addressed by the NEPA EIS analysis (40 CFR 1508).
Cumulative impactsThe impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (federal or non-federal) or person undertakes such other actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time.
CurrentA flow of electric charge in an electrical conductor.
Direct current (DC) transmissionTransmission of the electric charge in a unilateral direction (as opposed to “alternating current (AC) transmission, in which the electric charge oscillates, reversing direction and polarity 60 times per second).
DistributionAn interconnected group of lines and associated equipment for the local delivery of low-voltage electricity between the transmission network and end users.
Easement (private land)A grant of certain rights to the use of a piece of land. A grant of easement across a private parcel for a transmission line typically includes the right to enter the easement area to build, maintain, and repair transmission facilities, including access roads. Permission for these activities is included in the negotiation process for acquiring easements over private land. The land itself remains in private ownership.
Eminent domainWhen a company acquires property for public use through a court action, in which a court decides that the proposed subsequent use is in the public interest and also determines the compensation to be paid to the owner.
Environmental impact statement (EIS)The end product of the NEPA process for major federal actions with significant effects on the environment. An EIS is a comprehensive public document that analyzes the impacts of a major federal action that may significantly affect the quality of the human environment. When complete, it is a tool for decision making as the EIS describes the positive and negative environmental effects of a proposed action, describes alternative actions, and provides an analysis of environmental impacts and ways to mitigate such impacts across all alternatives considered in detail. An EIS examines physical and biological resources, resource uses, fire management, special designations, and social and economic conditions.
Existing corridorA linear area designated by law or in a land use plan that is or historically has been the preferred location for placement of linear rights of way, including transmission lines.
Federal Energy Regulatory Commission (FERC)A quasi-independent regulatory agency having jurisdiction over interstate electricity sales and interstate transmission service.
Human environmentThe natural and physical environment and the relationship of people with the environment.
Impacts (effects)Direct impacts (or effects) which are caused by the action and occur at the same time and place. Direct impacts include ecological, aesthetic, historical, cultural, economic, social, and health. Indirect impacts are caused by the action and are later in time or farther removed in distance. Indirect impacts may include growth inducing changes in the pattern of land use, population density or growth rate, and related effects on air and water or other natural systems. Also see Cumulative Impacts.
Kilowatt (kW)One thousand watts.
Lead federal agencyThe agency or agencies preparing, or having taken primary responsibility for preparing, an EIS as required by NEPA. For the Zephyr Power Transmission Project, the Bureau of Land Management (BLM) is anticipated to be the lead agency responsible for preparing the EIS.
LoadThe amount of electric power delivered or required by any specific point or points on a system. The requirement originates at the energy-consuming equipment of the consumers.
Megawatt (MW)One million watts.

  • Avoiding the impact altogether by not taking a certain action or parts of an action.

  • Minimizing the impact by limiting the degree or magnitude of the action and its implementation.

  • Rectifying the impact by repairing, rehabilitating, or restoring the affected environment.

  • Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.

  • Compensating for the impact by replacing or providing substitute resources or environments.

National Environmental Policy Act (NEPA) of 1969NEPA is a federal statute that contains procedures to ensure that federal agency decision makers take environmental factors into account. The two major purposes of the NEPA process are citizen involvement and better informed decisions. NEPA establishes national environmental policy and goals for the protection, maintenance, and enhancement of the environment, and provides a process for implementing these goals within the federal agencies. NEPA also establishes the Council on Environmental Quality (CEQ) and requires an environmental impact statement on all major Federal actions significantly affecting the quality of the human environment.
Notice of Intent (NOI)An NOI is a public notice, published in the Federal Register, announcing that an EIS is being prepared and considered in the decision making for a proposed action. The NOI also provides background information on the proposed project in preparation for the scoping process.
Open houseAn applicant-sponsored event in which information is provided to and received from stakeholders in an open forum. Open houses on the Zephyr Power Transmission Project will be opportunities for landowners and the public to meet with the project team and discuss their issues and concerns first-hand with subject matter experts.
Open seasonAn industry term to describe the timeframe during which an applicant solicits market participation from potential customers to ship a commodity on its proposed project. For the Zephyr Power Transmission Project, the Open Season is designed to determine interest from wind developers to secure capacity on DATC’s transmission line.
Opportunity (routing)A resource or condition that can accommodate a transmission line route, including and especially existing utility or transportation corridors.
Plan of Development (POD)A document submitted to the lead federal agency in support of an application for a Right-of-Way Grant. The POD for the Zephyr Power Transmission Project will include details on the proposed project, including a map of a proposed route, construction details and schedule, and an overview discussion of measures proposed to address sensitive resources along the project.
Pre-application phaseThe phase the Zephyr Power Transmission Project is considered to be in until the amended POD is filed and the pre-scoping process commences.
Pre-scopingPart of the lead federal agency’s environmental review process occurring before issuance of the NOI during which the agency conducts a preliminary internal review and compilation of potential environmental concerns in the vicinity of a proposed project. Information from this process is then incorporated into the NOI to define the scope of issues and alternatives proposed for analysis in the EIS for public consumption and comment.
Preliminary corridorFor the purposes of the Zephyr Power Transmission Project, a preliminary corridor is the geographic area extending from the point of origin in of the project in Wyoming to the point of end in Eldorado Valley within which a route corridor could be developed for additional evaluation (typically used to develop a working alignment for the initial screening of alternatives). Preliminary corridors were bound by the general limits of the study area and excluded broad areas of regional constraints while considering routing opportunities such as existing transmission lines. The study area for the Zephyr Power Transmission Project included several major preliminary corridors in which route corridors were considered.
Proposed route (applicant)The route of the Zephyr Power Transmission Project as sited and proposed by Zephyr Power Transmission Company LLC and presented to the federal agencies for their consideration in applications for right-of-way grants.
Record of Decision (ROD)The document that is prepared to substantiate a decision based on an EIS (in this case, issuing a Right-of-Way Grant). Issuance of the ROD is the final step for the lead federal agency and the cooperating agencies in the EIS process. The ROD states the final agency decisions, identifies the alternatives considered, and discusses mitigation, enforcement, and monitoring commitments.
ReliabilityElectric system reliability has two components: 1) adequacy and 2) security. Adequacy is the ability of the electric system to supply to aggregate electric demand and energy requirements of customers at all times. Security is the ability of the electric system to withstand sudden disturbances. The degree of reliability may be measured by the frequency, duration and magnitude of adverse effects on consumer services.
Renewable Portfolio Standard (RPS)A mechanism to increase renewable energy generation using a cost-effective, market-based approach which requires electric utilities to supply a specified minimum amount of customer load with electricity from eligible renewable sources. The state of California has an RPS of 33 percent by 2020, in addition to a greenhouse gas reduction law. Nevada has an RPS of 25 percent by 2025.
Right-of-Way (ROW) GrantAn authorization to use or occupy a specific piece of public land for a certain project, such as a road, pipeline, transmission line, or communication site. A ROW Grant authorizes rights and privileges for a specific use of the land for a specific period of time. For the Zephyr Power Transmission Project, this includes the construction, operation, maintenance, and termination of the transmission line and its facilities. Generally, a ROW Grant is for no longer than 30 years.
Route alternativeA route under consideration within a route corridor that potentially meets the purpose of and need for the Zephyr Power Transmission Project. Route alternatives may be identified to meet commercial needs, avoid environmentally sensitive areas, or be based on stakeholder comments.
Route corridorThe area, approximately 20 miles wide, in which a route alternative could be identified. If an environmentally sensitive area was found, the route alternative alignment could be shifted within the corridor to avoid adverse impacts to the sensitive area.
RoutingThe process used to identify preliminary corridors within the study area, then identify route corridors and route alternatives, and evaluate those alternatives to determine an applicant-proposed route.
ScopingPart of the federal environmental analysis process required under NEPA in which potential significant issues are identified for detailed analysis. Scoping includes, but is not limited to, a formal scoping period early in the analysis process in which members of the public are invited to review the proposed project and identify possible issues or concerns.
SitingSee ‘Routing’
StakeholdersA person, group or organization with an interest in or concern about a project. On the Zephyr Power Transmission Project, the definition of stakeholders includes but is not limited to landowners, public officials, government agencies, tribes, environmental groups, and businesses.
Study areaThe broad geographic area evaluated for routing on a project. The study area for the Zephyr Power Transmission Project was designed to be large enough to include ancillary facilities, including roads, structures, and areas needed for construction. The route corridors under evaluation are located within the study area.
Technical reportA series of sections, chapters or reports that are compiled by an Applicant and its contractor to document the existing conditions along the proposed route and alternatives provided to the lead federal agency for use by them and the third party contractor in development of the EIS. On the Zephyr Power Transmission Project, the technical report will also include a preliminary discussion of potential environmental effects of the project and mitigation to address those effects.
Temporary Use Permit (TUP)A permit given for temporary use of federally managed lands. A TUP is typically issued for the construction of a project, followed by a special use permit or long-term ROW Grant for the operation of the project.
Third-party contractorThe contractor that assists the lead federal agency in preparing the EIS for the project. The third party contractor is paid by the Applicant but receives direction exclusively from the lead federal agency.
Transmission systemAn interconnected group of electric transmission lines and associated equipment for moving or transferring electric energy in bulk between points of supply and points at which it is transformed for delivery over the distribution system lines to consumers, or is delivered to other electric systems.
WattThe unit of measure for calculating the power of a circuit.

Council on Environmental Quality, NEPA Implementing Regulations
U.S. Department of Energy/Energy Information Administration
U.S. Fish and Wildlife Service, NEPA Glossary
U.S. EPA, Renewable Portfolio Standards Fact Sheet