mkdocs theory added and additional module to create tables of relevant parameters, including a test

- power [MW]

- heat pump power [MW]

- capex (Capital expenditure) [Million €/$]

- opex (Operational expenditure) in first year [Million €/$]

- capex (Capital expenditure) [Million €]

- opex (Operational expenditure) in first year [Million €]

- utc (Unit Technical Cost [cts/kWH])

- npv (Net-present-value) [Million €/$]

- npv (Net-present-value) [Million €]

- hprod (Discounted Heat Produced) [MWh]

- cop (coefficient of performance of system) [-]

- cophp (coeffecient of performance of heat pump) [-]

- cophp (coefficient of performance of heat pump) [-]

- pressure for driving the thermal loop (wells+reservoir) [bar]

- flow rate [m³/hr]

- reservoir depth [m]

Therefore the estimated power and hprod are lower than the actual power and hprod of the system, which includes heat from electricity consumption in the ESP and heatpump.

The reason to do so is to avoid attributing produced energy which is not renewable, as renewable energy, such that utc for the goeothermal heat can be used as reference for feed-in tariffs and subsidies.

For details on how these parameters are calculated we refer users to the [Thermogis calculation webpage](https://www.thermogis.nl/en/calculation-model).

as well as the theory section

For details on how these parameters are calculated we refer users to the theory section as well as [Thermogis calculation webpage](https://www.thermogis.nl/en/calculation-model).

For energy conversion to electricity, and chill the power concerns net electricty production and net chill respectively

The following CAPEX and OPEX items are included in the cashflow model:

- CAPEX<sub>wells</sub>

- CAPEX<sub>stimulation</sub>

- CAPEX<sub>plant</sub>

*CAPEX [€] = CAPEX<sub>wells</sub> [+ CAPEX<sub>stimulation</sub>] + CAPEX<sub>plant</sub>*

*OPEX [€] per year = OPEX<sub>plant</sub> + [ + OPEX<sub>hp</sub> ] + OPEX<sub>Econs</sub> + *

## Well costs 

*CAPEX<sub>wells</sub> = 375,000 + 1050 ∙s<sub>curve</sub>∙ z<sub>tvdtop</sub> +  0.3∙ ∙s<sub>curve</sub>∙  z<sub>tvdtop</sub>^2*

The well costs are calculated based on the top depth of the reservoir *z<sub>top</sub>*

*CAPEX<sub>wells</sub> [€] = wscale ∙ ( wc0 + wc1 ∙ scurve ∙ z<sub>top</sub>[m] + wc2 ∙ (scurve ∙ z<sub>top</sub>)^2 [m^2] )*

The scurve is a scaling factor for deviated wells, which is used to account for the curvature of the well trajectory, 

i.e.  for deviated and horizontal well layouts scurve is larger than 1, and for vertical wells it is equal to 1. 

So *scurve ∙ z<sub>top</sub>*  can be interpreted as the along hole depth (AHD) or Measured Depth (MD) of the well.

## stimulation costs

## Well Stimulation costs

If stimulation is activated, the stimulation costs can be  included in the CAPEX modell, e.g.:

If stimulation is activated through *use_stim*, the stimulation costs are  included in the CAPEX model, by:

*CAPEX<sub>stimulation</sub> = 0.75 million€*

*CAPEX<sub>stimulation</sub> [€] = capex_stim ∙ 10^6*

## Plant costs

## Geothermal Plant costs

*CAPEX<sub>plant</sub> = CAPEX<sub>base</sub> + CAPEX<sub>other,var</sub> ∙ P<sub>net</sub>*

*CAPEX<sub>plant</sub> [€]= CAPEX<sub>base</sub> [million €] ∙ 10^6   + CAPEX<sub>other,var</sub> [€/kW] ∙ POWER [MW] ∙ 10^3

where:

- CAPEX<sub>base</sub> is the base capital expenditure, which includes the cost of the geothermal plant and other fixed costs.

- CAPEX<sub>other,var</sub> is the variable capital expenditure, which includes the cost for scaling to a certain capacity of geothermal power

- P<sub>net</sub> is the net power output of the geothermal plant, which is the geothermal power output  

- POWER is the net power output of the geothermal plant, which is the geothermal power output  

corrected for the conversion efficiency any parasitic power losses. For direct heat (including heat pump) it does not include conversion to heat of the ESP power,

and added heat in the heatpump from the compressor.

## Operating Expenditure (OPEX)

In the [directheat with heat pump](../energyconversion/directheatHP.md) there are additional CAPEX<sub>hp,var</sub> and OPEX<sub>hp</sub> parameters for the heat pump system, 

which are included in the cashflow model as follows:

*CAPEX<sub>hp</sub> = CAPEX<sub>hp,var</sub> [€/kW] ∙ POWER [MW] ∙ 10^3*

where:

- CAPEX<sub>hp,var</sub> is the variable capital expenditure for the heat pump system, which includes the cost of scaling to a certain capacity of geothermal power.

##  Operating Expenditure 

accounts for yearly operational expenses of the geothermal plant, which include maintenance, repairs, and other ongoing costs.

*OPEX = OPEX<sub>base</sub> + OPEX<sub>power</sub> ∙ P<sub>net</sub> + OPEX<sub>heat,var</sub> ∙ Hprod<sub>y</sub>*

*OPEX<sub>plant</sub> [€] per year  = OPEX<sub>base</sub> [€] + OPEX<sub>power</sub> [€/kw] ∙ POWER [MW] ∙ 10^3  + OPEX<sub>heat,var</sub> [€/kwh] ∙ Hprod<sub>y</sub> [MWh] ∙ 10^3*

where:

- OPEX<sub>power</sub> is the scaling of operating expenditure per unit of net power capacity.

- OPEX<sub>heat,var</sub> is the additional operating expenditure per unit of net heat output, 

which includes the cost of operating and maintaining the geothermal plant for direct heat applications.

- Hprod<sub>year</sub> is the geothermal energy producted  of the geothermal plant on a yearly basis [kWh].

- Hprod<sub>y</sub> is the geothermal energy producted  of the geothermal plant on a yearly basis [kWh/y].

the proposed values for these parameters are dependent on the energy conversion technology and the type of geothermal resource [directheat](../energyconversion/directheat.md), 

[directheat with heat pump](../energyconversion/directheatHP.md), [chiller](../energyconversion/chiller.md) and [ORC](../energyconversion/orc.md) and can be adjusted in the ThermoGIS configuration file.

In the [directheat with heat pump](../energyconversion/directheatHP.md) there are additional CAPEX<sub>hp,var</sub> and OPEX<sub>hp</sub> parameters for the heat pump system, 

which are included in the cashflow model as follows:

In the [directheat with heat pump](../energyconversion/directheatHP.md) there is additional  OPEX<sub>hp</sub> which is

included in the cashflow model as follows:

*OPEX<sub>hp</sub> = OPEX<sub>hp</sub> [€/kW] ∙ POWER [MW] ∙ 10^3*

where:

- OPEX<sub>hp</sub> is the operating expenditure for the heat pump system, which includes the cost of operating and maintaining the heat pump system

*CAPEX<sub>hp</sub> = CAPEX<sub>hp,var</sub> ∙ P<sub>net</sub>*

##  Power consumption

A part of the operating expenditure, the power consumption of the geothermal plant is also considered in the cashflow model.

*OPEX<sub>Econs_cost</sub> = Eprice ∙ (ESP<sub>Econs</sub>  + parasitic<sub>Econs</sub> + heatpump<sub>Econs</sub>)*

where:

*OPEX<sub>hp</sub> = OPEX<sub>hp</sub> ∙ P<sub>net</sub>*

- *ESP<sub>Econs</sub>* is the power consumption of the ESP pump, in accordance to the COP of the geothermal thermal loop, and efficiency of the ESP

- *parasitic<sub>Econs</sub>* is the parasitic power consumption of the geothermal plant, which includes the power consumption of a chiller.

- *heatpump<sub>Econs</sub>* is the power consumption of the heat pump system, in accordance to the COP of the heat pump system.

- *Eprice* is the electricity price in cts/kWh, which is the cost of electricity used to power the ESP (chlling  and heat pump system).

# economic model

The economic model takes as input the CAPEX and OPEX values [€], as well as the yearly produced energy [kWh/y] and calculates the discounted cash flow for each year 

of the economic lifetime of the geothermal system.

The well CAPEX is not distributed over the *drilltime* in years but all assummed in first year of *ECONlifetime*, jointly with additional investments for stimulation if applicable.

The other CAPEX times which are assumed to be at the start of the economic lifetime.

OPEX is assumed to be paid at the end of each year, and is calculated based on the total OPEX for the year.

OPEX terms are corrected for *inflation*, affecting the second and following years.

The produced energy is calculated from the product of geothermal POWER and the *loadhours* per year, 

and is corrected for the *tax rate*.

## Discounted cashflow model

The heat production is discounted to the present value with the *IRR*, and the net income is calculated for each year.

The following steps are made:

- present value of loan is calculated as *CAPEX . debt*

- yearly payment  is calculated as the annuity payment

for the present value of the loan taking *interest* rate and *ECONlifetime* as loan term

- depreciation cost is calculated as CAPEX divided by the *ECONlifetime* in years

- tax deduction:  is minus ( sum of inflated OPEX, depreciation cost and interest payment ) times *tax*

- netincome is calculated as sum of inflated OPEX, yearly payment and tax deduction 

- yearly energy produced is taxated by multiplication by (1 - *tax*), resulting in the taxated energy produced

The yearly netincome and yearly taxated energy produced is subsequently discounted based on the 

 *IRR* rate resulting in discounted income and discounted taxated heat produced.

## Unit Technical Cost (UTC) or Levelized Cost Of Energy (LCOE)

The UTC (Unit Technical Cost) or socalled LCOE (Levelized Cost Of Energy) 

is calculated as:

*UTC [€cts/kWh] =  10^-2 ∙ the discounted income [€] / discounted taxated energy produced [kWh]*

## Net Present Value (NPV)

The NPV (Net Present Value) is calculated in pythermogis as:

*NPV[€]  = discounted taxated heat produced [kWh]  ∙ (utc_cutoff - UTC) ∙ 10^-2 * 

or afterwards by using *Hprod* from the [KPI](../kpiperformance.md) as:

*NPV[€]  = hprod [MWh]  ∙ (1-*tax*) ∙  (utc_cutoff - UTC) ∙ 10^4* 

where:

- *utc_cutoff* is the UTC value which is commercial or garanteed to r operator of the geothermal system

calculated afterwards as the sum of the discounted income minus the CAPEX.

 No newline at end of file

## Geothermal Resource Parameters

The geothermal resource parameters include:

- Reservoir depth: The depth at which the geothermal resource is located, typically measured in meters below ground level.

- Reservoir thickness: The vertical extent of the geothermal resource, which can influence the amount of heat available.

- Temperature: The temperature of the geothermal resource, which is a critical factor in determining its energy potential.

- Reservoir flow properties: These include permeability and porosity, which determine how easily fluids can move through the reservoir and how much fluid can be stored.

- Salinity: The concentration of dissolved salts in the geothermal fluid, which influence temperature (and pressure dependent) properties such as density and viscosity.

- Temperature gradient: The rate at which temperature increases with depth in the geothermal resource, typically expressed in degrees Celsius per kilometer (°C/km).

- Aquifer top depth *ztop^*: The depth at which the geothermal resource is located, typically measured in meters below ground level.

- Aquifer thickness *H*: The vertical extent of the geothermal resource, which can influence the amount of heat available.

- Temperature *Taq*: The temperature of the geothermal resource, which is a critical factor in determining its energy potential.

- Reservoir flow properties *k* and *por*: These include permeability and porosity, which determine how easily fluids can move through the reservoir and how much fluid can be stored.

- Salinity *s*: The concentration of dissolved salts in the geothermal fluid, which influence temperature (and pressure) 

dependent properties such as density and viscosity.

These can be specified as site-specific parameters, or as a grid input,  and a number of them as a distribution 

| Technical parameter             | symbol | value                       | unit       |

|---------------------------------|--------|-----------------------------|------------|

| Aquifer/fault top depth         | z      | varies                      | m          |

| Aquifer/fault thickness         | H      | 1-100                       | m          |

| Aquifer/fault top depth         | ztop   | varies                      | m          |

| Aquifer/fault thickness         | H      | 10-500                      | m          |

| aquifer net-to-gross            | Ng     | 1                           | -          |

| aquifer permeability            | k      | fixed or f(porosity(depth)) | millidarcy |

| aquifer porosity                | por    | 0.05-0.4                    | -          |

| aquifer permeability            | k      | fixed or f(porosity)        | millidarcy |

| aquifer temperature             | Taq    | temperature model at z+0.5H | °C         |

| aquifer water salinity          | s      | Equation                    | ppm        |

| aquifer water salinity at z=0   | s0     | 0                           | ppm        |

The depth dependent salinity s (ppm) is based on the following equation:

*s=s₀+ s<sub>grad</sub> (z+0.5H)*

*s=s₀+ s<sub>grad</sub> (ztop+0.5H)*

where z is top depth and H thickness of the aquifer, both in m

## introduction

In the EU27, Netherlands ranks first in terms of exploited geothermal heating and cooling per surface area, 

and third in terms of the number of installed geothermal plants for geothermal district heating (EGEC, 2024). 

The first successful deep geothermal system was completed less than 20 years ago in 2007. 

pyThermoGIS is a Python package that provides API access to pre-drill doublet simulations and economic calculations implemented in ThermoGIS.

[ThermoGIS](https://www.thermogis.nl/en) is a web-based information system for geothermal prospectivity that has originally been developed to support Geothermal development in the Netherlands, 

Over the past two decades, 84 deep geothermal wells in a depth range of 1500-3000 m have been drilled 

serving mostly as injection and production wells in a geothermal doublet configuration

(marked by complete reinjection of produced brines, Van Wees et al., 2012; Mijnlieff, 2020), 

with a total 6.9 PJ/y of geothermal heat produced in 2023 (Van der Molen and Tolsma, 2024)

with a total 6.9 PJ/y of geothermal heat produced in 2023 (Van der Molen and Tolsma, 2024). 

The Netherlands is currently one of the leading countries in Europe in terms of installed geothermal capacity for direct heating.

In the EU27, Netherlands ranks first in terms of exploited geothermal heating and cooling per surface area, 

and third in terms of the number of installed geothermal plants for geothermal district heating (EGEC, 2024). 

The first successful deep geothermal system was completed less than 20 years ago in 2007. 

At the heart of ThermoGIS is the [DoubletCalc1D](https://www.nlog.nl/en/tools) doublet technical performance assesment tool (van Wees et al., 2012), 

At the heart of pyThermoGIS and [ThermoGIS](https://www.thermogis.nl/en) is the [DoubletCalc1D](https://www.nlog.nl/en/tools) doublet technical performance assesment tool (van Wees et al., 2012), 

which is a software tool developed by TNO that calculates how much geothermal water can be pumped at a given pump power, 

taking into account well engineering aspects and specific subsurface conditions, including aquifer temperature, and reservoir flow properties.

pyThermoGIS is very flexible and  can be applied for:

- site-specific analysis

## Key Performance indicators

- [key performance indicators](kpiperformance.md): The key performance indicators (KPIs) are calculated based on the technical performance and economic model, 

  providing insights into the feasibility and profitability of geothermal projects. These include next to minput parameters:

  - Specific energy production (e.g., power in MWth or MWe)

  - Unit Technical Costs (e.g., €/kWh)

  - Net present value (NPV)

  - net power  (power in MWth or MWe)

  - Unit Technical Costs (UTC in  €ct/kWh)

  - Net present value (NPV in million €)

## References