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| 1 | +# SAM Economic Models: End Uses and Surface Applications |
| 2 | + |
| 3 | +[SAM Economic Models](SAM-Economic-Models.html) support a variety of geothermal end-use options and surface applications. |
| 4 | + |
| 5 | +See the [Theoretical Basis for GEOPHIRES End-use options documentation](Theoretical-Basis-for-GEOPHIRES.html#enduse-options) |
| 6 | +for details on the underlying physical simulation mechanics. |
| 7 | + |
| 8 | +## Electricity |
| 9 | + |
| 10 | +For pure electricity generation configurations, SAM Economic Models calculate standard project finance metrics, |
| 11 | +including a nominal Levelized Cost of Electricity (LCOE). |
| 12 | + |
| 13 | +### Examples: |
| 14 | + |
| 15 | +1. [example_SAM-single-owner-PPA](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA): 50 MWe |
| 16 | +1. [example_SAM-single-owner-PPA-6_carbon-revenue](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-6_carbon-revenue): Electricity with Carbon Credits |
| 17 | + |
| 18 | +See [SAM Economic Models documentation](SAM-Economic-Models.html#examples) for additional electricity examples. |
| 19 | + |
| 20 | +## Direct-Use Heat |
| 21 | + |
| 22 | +Direct-use heat configurations evaluate pure thermal energy extraction, reporting financial viability via the nominal |
| 23 | +Levelized Cost of Heat (LCOH) in $/MMBTU. |
| 24 | +Heat revenue is modeled as capacity payment revenue and included as the `Heat revenue ($)` cash flow line item. |
| 25 | + |
| 26 | +### Grid Electricity Consumption and Cash Flow Reporting |
| 27 | + |
| 28 | +In GEOPHIRES, pure direct-use heat and cooling configurations |
| 29 | +typically require parasitic pumping power purchased from the grid. The cost of this grid electricity is calculated |
| 30 | +and fully accounted for within GEOPHIRES' baseline OPEX calculations prior to executing the SAM financial engine. |
| 31 | + |
| 32 | +Because these costs are injected directly into the fixed O&M parameters passed to SAM, SAM's native grid-purchase |
| 33 | +mechanisms are bypassed. Consequently, the specific cash flow line items for `Electricity from grid (kWh)` |
| 34 | +and `Electricity purchase ($)` are intentionally removed from the final SAM cash flow profile report. |
| 35 | +This prevents the display of default zero values, which could otherwise mislead analysts into assuming parasitic power |
| 36 | +costs were omitted. |
| 37 | + |
| 38 | +### Examples: |
| 39 | + |
| 40 | +1. [example_SAM-single-owner-PPA-8_heat](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-8_heat): Direct-Use Heat |
| 41 | + |
| 42 | +## Cogeneration |
| 43 | + |
| 44 | +Combined Heat and Power (CHP) end-uses simulate both electricity and direct-use heat generation. |
| 45 | +The model outputs allocated metrics for both product streams, including `Electricity CAPEX ($/kWe)`, `Heat CAPEX ($/kWth)`, LCOE, and LCOH. |
| 46 | + |
| 47 | +### CHP Cost Allocation Ratio |
| 48 | + |
| 49 | +To separate the levelized costs of electricity and heat, GEOPHIRES utilizes the `CHP Electrical Plant Cost Allocation Ratio`. |
| 50 | +When calculating the levelized metrics, the total present value of annual costs includes not only CAPEX, but also OPEX, |
| 51 | +taxes, and debt service. By applying a CAPEX-derived allocation ratio to this total present value, the model |
| 52 | +mathematically forces the assumption that thermal OPEX and financing burdens scale exactly proportionally to thermal CAPEX. |
| 53 | +If the electrical power plant has a high O&M burden and the direct-use heat component has a relatively low O&M burden, |
| 54 | +applying the CAPEX ratio to the total PV will artificially inflate the LCOH and artificially lower the LCOE. |
| 55 | +Analysts should be aware of this proportional scaling approximation when evaluating granular CHP OPEX profiles. |
| 56 | + |
| 57 | +### Injection Temperature and CHP Topping Cycles |
| 58 | + |
| 59 | +In GEOPHIRES, adjusting the `Injection Temperature` for a Cogeneration Topping Cycle will affect the amount of direct-use heat produced, but it will **not** affect electricity production. |
| 60 | + |
| 61 | +This is the physically correct behavior. In a topping cycle, the geofluid flows sequentially: it first passes through the power plant (which extracts heat to generate electricity and rejects the fluid at a calculated thermodynamic exhaust temperature), and then passes through the direct-use application (which extracts the residual heat down to the user-defined `Injection Temperature`). |
| 62 | + |
| 63 | +Because the power plant sits upstream, its electricity production is governed entirely by the production temperature and its own exhaust temperature. Lowering the `Injection Temperature` simply increases the temperature delta across the downstream direct-use application, yielding more heat without altering the upstream power cycle. |
| 64 | + |
| 65 | +### Examples: |
| 66 | + |
| 67 | +1. [example_SAM-single-owner-PPA-7_chp](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-7_chp): Combined Heat and Power (CHP): Cogeneration Topping Cycle |
| 68 | +1. [example_SAM-single-owner-PPA-7b_chp-cc](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-7b_chp-cc): Combined Heat and Power (CHP): Carbon Credits |
| 69 | +1. [example_SAM-single-owner-PPA-7c](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-7c): Combined Heat and Power (CHP): Carbon Credits with fixed Surface Plant Capital Cost |
| 70 | +1. [example_SAM-single-owner-PPA-7d_chp-bottoming](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-7d_chp-bottoming): Combined Heat and Power (CHP): Cogeneration Bottoming Cycle |
| 71 | +1. [example_SAM-single-owner-PPA-7e_chp-parallel](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-7d_chp-parallel): Combined Heat and Power (CHP): Cogeneration Parallel Cycle |
| 72 | + |
| 73 | +## Absorption Chiller (Cooling) |
| 74 | + |
| 75 | +Cooling applications via absorption chillers are supported, providing a nominal Levelized Cost of Cooling (LCOC) in |
| 76 | +$/MMBTU. Cooling revenue is modeled as capacity payment revenue and included as the `Cooling revenue ($)` cash flow line item. |
| 77 | +Like Direct-Use Heat, parasitic electricity requirements are factored into the baseline OPEX prior to |
| 78 | +SAM execution. |
| 79 | + |
| 80 | +### Examples: |
| 81 | + |
| 82 | +1. [example_SAM-single-owner-PPA-9_cooling](https://gtp.scientificwebservices.com/geophires?geophires-example-id=example_SAM-single-owner-PPA-9_cooling): Cooling (Direct-Use Heat with Absorption Chiller Surface Application) |
| 83 | + |
| 84 | +## Limitations |
| 85 | + |
| 86 | +Heat Pump, District Heating, and Reservoir Thermal Energy Storage (SUTRA) surface applications are not currently supported for SAM Economic Models. |
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