Resource Characterization

The resource characterization inputs describe the energy available in the underground geology at the project site.

Resource Type

For Hydrothermal resources, the rocks have enough permeability, heat, and water to be useful immediately.

For Enhanced Geothermal System (EGS) resources, there is heat, but either water, or permeability, or both are missing and must be added during the project development and operation.

Total Resource Potential

The total resource potential is an estimate of the total size of the energy available in the underground thermal reservoir. SAM uses the value to calculate the number of times over the project life that new drilling would be required to renew the resource based on the reduction of the reservoir's temperature over time. As the system operates and draws heat from the reservoir, the reservoir temperature drops. After a number of years, there may be insufficient heat to maintain the steam temperature required to drive the plant, and new wells may need to be drilled to renew the resource by reaching another section of the reservoir where there is sufficient heat. Eventually, the reservoir may cool to the point that it is impossible to find more heat by drilling from the plant location. Total resource potential is meant to be a measure of how many times the reservoir can be renewed. For example, a 210 MW reservoir divided by 30 MW plant capacity could support up to seven renewals (210 ÷ 30 = 7).

Resource Temperature

The temperature of the reservoir at the depth given by the resource depth.

Resource Depth

The depth below ground at which the temperature specified by the resource temperature exists.

Note. In general, the higher the temperature of the resource, the lower the cost of energy generated by the plant. However, SAM does not handle systems that operate at extremely high steam temperatures that require special equipment.

Reservoir Parameters

The reservoir parameters describe the geologic formation. SAM provides four options for calculating the change in reservoir pressure. The option you choose affects the plant's overall efficiency, which depends on the design parameters that SAM displays under Calculated Design. The design value determines the pumping power or parasitic load required by the plant.