Phase II - Resource Exploration and Confirmation
GEA Development Phase II: Resource Exploration and Confirmation
- Phase I - Resource Procurement and Identification
- Phase II - Resource Exploration and Confirmation
- Phase III - Permitting and Initial Development
- Phase IV - Resource Production and Power Plant Construction
The information for this page was taken directly from Geothermal Reporting Terms and Definitions: A Guide to Reporting Resource Development Progress and Results to the Geothermal Energy Association (GEA, November 2010)
Phase II Criteria
In reporting a Phase II geothermal project to the GEA the developer must ascertain whether or not the project being reported meets the following specified criteria. The development criteria are divided into three different subsections of Phase II geothermal development (Resource, Transmission, and External Development). It is not necessary that a geothermal project meet all of the criteria listed. The number of criteria that a project must meet in each subsection of geothermal Phase II development is specified below.
1. Resource Development Criteria
For a project to be considered a Phase II project at least one of the following Resource Development criteria must be met:
- Temperature Gradient Holes (TGH) Drilled
- A sufficient number of TGH holes have been drilled which measure temperature gradients that indicate a potential geothermal resource over a large enough thermal anomaly to justify further drilling.
- Slim Hole Drilled
- At least one 3” or greater diameter slim hole drilled to a depth that penetrates a portion of the geothermal reservoir.
- One Full Size Discovery Well Drilled
- One full sized well completed with bottom-hole temperatures and flow rates sufficient for a commercial size geothermal well (typically 3 to 5 MW) capable of simple payback given existing economic conditions and commercial terms for selling power.
2. Transmission Development Criteria
For a project to be considered a Phase II project at least one of the following Transmission Development criteria must be met.
- Interconnection application submitted and queue position established
- Application to construct necessary transmission lines from the geothermal resource development project to the grid have been submitted to the utility for which the project will interconnect.
- Transmission feasibility studies underway
- The developer has begun the analysis of necessary steps that must be taken to connect its project to an identified utilities transmission system.
3. External to Resource Development Criteria
For a project to be considered a Phase II project at least one of the following External to Resource Development criteria must be met:
- Permit for Slim Hole Drilling Applied for or Approved
- The developer must have obtained a permit for the drilling of a slim hole to a depth that penetrates a portion of the geothermal reservoir.
- Permit for Production Well Drilling Applied for or Approved
- The developer must have obtained, or submitted an application for, a permit for the drilling of a full size production well from the appropriate state agency.
Phase II Terms & Definitions
The following terms and their definitions are to be applied to geothermal projects which are in the Phase II stage of geothermal development.
- Possible Resource Estimate
- For a geothermal project to be considered a Phase II Possible Resource it must exhibit known characteristics which lead the developer to believe, with a level of confidence appropriate to the stage of development, that further development of the geothermal project may lead to potential economic utilization of the resource.
Specifically, as mentioned above, the developer of a geothermal project must fulfill one of the criteria listed in the Phase II Resource Development Category, one of the criteria listed in the Phase II Transmission
- Development Category, and one of the criteria listed in the Phase II External Development Category.
It should be noted that the Possible Resource Estimate should not be used as a value to indicate the potential installed capacity of a geothermal power plant. Rather, it is the estimated value of the subsurface geothermal resource.
- Possible Planned Capacity Addition (PCA) Estimate
- The Phase II Possible Planned Capacity Addition (PCA) estimate is that portion of a Possible Resource that the developer deems to be viable for the economic production of electricity under existing economic conditions. Also, the PCA estimate should represent the potential capacity that is currently controlled by the developer, and not the total capacity that the developer intends to control and produce in the future. In other words, if the developer were to utilize the geothermal resource under its control to produce electricity via a geothermal power plant the Phase II PCA estimate would be the power plants estimated installed capacity. If the developer were expanding a currently operating plant the Phase II Possible PCA estimate would be the estimated capacity to be added to the plants current installed capacity.
Phase II - Projects
GEA Annual US Geothermal Power Production and Development Reports