Hydroelectric power projects are complex and can be lengthy and expensive to construct. Hydropower projects usually have high initial costs, low operating costs and project lives of 50 years or more. Even with excellent hydro resources, engineering must be thorough to insure a positive return on investment. This consists of an involved process with many things to consider. Project development phases include reconnaissance, feasibility, licensing & design, and finally construction.

A reconnaissance study is a preliminary feasibility study that serves to determine if the project warrants a full feasibility study. This is usually the very first step when considering a hydroelectric project for development.

A reconnaissance study includes the following elements:

  1. Compilation of Existing Data and Prior Studies
    • Identification of data availability and quality and data gaps
    • Water rights, licensing claims
    • Land ownership, easements
    • Hydrology
    • Geology
    • Fish presence and stream habitat
    • Presence of protected or special status species
  2. Project Description
    • Size, type, and location of project including transmission and access
    • Assessment of physical works
    • Method of construction and materials
  3. Need for Power
    • Demand, seasonal load pattern
    • Development of power requirement forecast
  4. Hydrology Resource Evaluation - This analysis entails a site evaluation of water resources, stream gage data collection and stream-flow modeling.
  5. Site Description – location of the project, water resource, landscape and land ownership
  6. Preliminary Discussion of Environmental Impact – description of the resources and how they could potentially be impacted by construction and operation of the project
  7. Identification of Licensing and Permitting Requirements
  8. Assessment of Constraints and Critical Issues
    • Legal/Institutional, Licensing and Environmental, and Engineering Site issues.
  9. Economic Feasibility
    • Cost Estimates for Licensing, Design, and Construction
    • Development of Power Benefit Stream and Cost of Energy
  10. Final Report - Summary of findings with a recommendation for next course of action regarding the project.

A feasibility study is a detailed study to determine the technical, economic, and environmental feasibility of potential hydroelectric development. Considerable time is spent in the examination and assessment of the proposed project. Decisions are made at this stage to determine if the project should be continued.

A feasibility study is performed as follows:

  • Pre-construction Investigations and Evaluations including:
    • Surveying and Topographic Mapping
    • Geotechnical/Geophysical Investigations
    • Hydrologic Studies and Stream Gauging
    • Permitting - Environmental and Fish Studies
  • Project Description - a description of what the project wishes to accomplish, who will benefit from the project, and the construction techniques involved with the project.
  • Project Alternatives - exploration of changes in various aspects of the project including routes, energy sources, materials, location, and others.
  • Conceptual Engineering - comments and thoughts for all parts of the hydroelectric system including:
    • Diversion
    • Intake/Outlet
    • Major Equipment Selection
    • Power Conduit
    • Powerhouse
    • Spillway
    • Switchyard
    • Transmission Lines
    • Tunnel
  • Identification of Physical Works - determination of penstock route, powerhouse location, project access, and intertie connections
  • Computation of Project Power Output
  • Confirmation of Power Demand
  • Development of Project Cost Estimate and Schedule
  • Economic Evaluation - examines the long-term financial benefits of the project
  • Preliminary Site Control Plan - Plan to consider safety, logistics, and other matters involved with construction.
  • Identification of Critical Issues
  • Assessment of Legal, Institutional, and Financial Issues
  • Documentation of Findings from the Feasibility Study
  • Other Considerations - any other issue not considered in the feasibility study:
    • Monthly Stream Flow Distributions
    • Flood Hydrographs
    • Reservoir Area-Capacity Curves
    • Annual Firm Energy
    • Average Annual Energy
    • Installed Capacity
    • Active Storage Capacity

The design process is the time when the characteristics and features of the project are explored, determined, and integrated together. This involves complex modeling, in-depth analysis of the site and materials, and integration of the parts into one large system.

Tasks done in the design phase include:

  • Completion of License Application and Permits
  • Performance of Engineering Calculations for Mathematical Support of the Project
  • Preparation of a detailed Engineering Design Report
  • Preparation of Final Design Drawings and Specifications
  • Preparation for Payments for Materials Acquisition
  • Establishment of QA/QC requirements for project construction, testing, and equipment installation.

Construction is the final stage of the process in hydroelectric development. This is the act of building the system and installing it into the hydro site. This is the most visible stage of the project. Further Information regarding the process of hydroelectric development can be found on the Federal Energy Regulatory Commission (FERC) and Alaska Dam Safety websites.