Added loan tenor option

main.py

@@ -41,7 +41,7 @@ app.add_middleware(
 #     return RedirectResponse(redirect_url)
 
 
-@app.get("/solarpv")
+@app.get("/solarpv/lcoe")
 def get_lcoe(pv_assumptions: Annotated[SolarPVAssumptions, Query()]):
     return calculate_lcoe(pv_assumptions)
 

model.py

@@ -88,18 +88,18 @@ def calculate_cashflow_for_renewable_project(
         .with_columns(
             CFADS_mn=pl.col("EBITDA_mn"),
         ))
-    # Calculate DCSR-sculpted debt % of capital cost if debt % is not provided
-    if (assumptions.debt_pct_of_capital_cost is None) or assumptions.targetting_dcsr:
+    # Calculate DSCR-sculpted debt % of capital cost if debt % is not provided
+    if (assumptions.debt_pct_of_capital_cost is None) or assumptions.targetting_dscr:
         model = (
             model.with_columns(
-                Target_Debt_Service_mn=pl.when(pl.col("Period") == 0)
+                Target_Debt_Service_mn=pl.when((pl.col("Period") == 0) | (pl.col("Period") > assumptions.loan_tenor_years))
                 .then(0)
-                .otherwise(pl.col("CFADS_mn") / assumptions.dcsr),
+                .otherwise(pl.col("CFADS_mn") / assumptions.dscr),
             )
         )
         assumptions.debt_pct_of_capital_cost = pyxirr.npv(
             assumptions.cost_of_debt,
-            model.select("Target_Debt_Service_mn").__array__()[0:, 0],
+            model.select("Target_Debt_Service_mn").__array__()[0:assumptions.loan_tenor_years+1, 0],
         ) / (assumptions.capital_cost / 1000)
         # print(assumptions.debt_pct_of_capital_cost)
         # assumptions.equity_pct_of_capital_cost = 1 - assumptions.debt_pct_of_capital_cost
@@ -133,7 +133,7 @@ def calculate_cashflow_for_renewable_project(
             ),
         ))
     # Calculate amortization, assuming a target DSCR
-    if assumptions.targetting_dcsr:
+    if assumptions.targetting_dscr:
         model = (
             model.with_columns(
                 Amortization_mn=pl.when(pl.col("Period") == 0)
@@ -149,13 +149,13 @@ def calculate_cashflow_for_renewable_project(
         # Calculate amortization, assuming equal amortization over the project lifetime
         model = (
             model.with_columns(
-                Amortization_mn=pl.when(pl.col("Period") == 0)
+                Amortization_mn=pl.when((pl.col("Period") == 0) | (pl.col("Period") > assumptions.loan_tenor_years))
                 .then(0)
                 .otherwise(
                     assumptions.debt_pct_of_capital_cost
                     * assumptions.capital_cost
                     / 1000
-                    / assumptions.project_lifetime_years
+                    / assumptions.loan_tenor_years
                 ),
             ))
     model = (
@@ -177,7 +177,7 @@ def calculate_cashflow_for_renewable_project(
             model.loc[period, "Interest_Expense_mn"] = (
                 model.loc[period, "Debt_Outstanding_BoP_mn"] * assumptions.cost_of_debt
             )
-            if assumptions.targetting_dcsr:
+            if assumptions.targetting_dscr:
                 model.loc[period, "Amortization_mn"] = min(
                     model.loc[period, "Target_Debt_Service_mn"]
                     - model.loc[period, "Interest_Expense_mn"],
@@ -187,12 +187,12 @@ def calculate_cashflow_for_renewable_project(
                 model.loc[period, "Debt_Outstanding_BoP_mn"]
                 - model.loc[period, "Amortization_mn"]
             )
-            if period < assumptions.project_lifetime_years:
+            if period < assumptions.loan_tenor_years:
                 model.loc[period + 1, "Debt_Outstanding_BoP_mn"] = model.loc[
                     period, "Debt_Outstanding_EoP_mn"
                 ]
     model = pl.DataFrame(model)
-    if not assumptions.targetting_dcsr:
+    if not assumptions.targetting_dscr:
         # Target debt service = Amortization + Interest
         model = (
             model.with_columns(
@@ -204,7 +204,7 @@ def calculate_cashflow_for_renewable_project(
             )
         )
         # Calculate DSCR
-        assumptions.dcsr = (
+        assumptions.dscr = (
             model["EBITDA_mn"] / model["Target_Debt_Service_mn"]
         ).min()
 

schema.py

@@ -72,6 +72,15 @@ class SolarPVAssumptions(BaseModel):
             description="Project lifetime in years",
         ),
     ] = 25
+    loan_tenor_years: Annotated[
+        Optional[int],
+        Field(
+            ge=5,
+            le=50,
+            title="Loan Tenor (years)",
+            description="Loan tenor in years",
+        ),
+    ] = 25
     degradation_rate: Annotated[
         float,
         Field(
@@ -81,8 +90,8 @@ class SolarPVAssumptions(BaseModel):
             description="Annual degradation rate as a decimal, e.g., 0.01 for 1%",
         ),
     ] = 0.005
-    dcsr: Annotated[
-        float,
+    dscr: Annotated[
+        Optional[float],
         Field(
             ge=1,
             le=10,
@@ -90,17 +99,17 @@ class SolarPVAssumptions(BaseModel):
             description="Debt service coverage ratio",
         ),
     ] = 1.3
-    targetting_dcsr: Annotated[
+    targetting_dscr: Annotated[
         bool,
         Field(
             title="Target DSCR?",
-            description="Whether to target the DSCR or the debt percentage. If True, the DCSR will be used to calculate the debt percentage.",
+            description="Whether to target the DSCR or the debt percentage. If True, the DSCR will be used to calculate the debt percentage.",
         ),
     ] = True
 
     @model_validator(mode="after")
     def check_sum_of_parts(self):
-        if not self.targetting_dcsr:
+        if not self.targetting_dscr:
             assert (
                 self.debt_pct_of_capital_cost is not None
             ), "Debt percentage must be provided"
@@ -176,6 +185,18 @@ class SolarPVAssumptions(BaseModel):
             }
         return values
 
+    @model_validator(mode="before")
+    @classmethod
+    def loan_tenor_less_than_lifetime(cls, values):
+        # If loan tenor is not provided, set it to project lifetime
+        if values.get("loan_tenor_years") is None or values.get("loan_tenor_years") == "None":
+            values["loan_tenor_years"] = values.get("project_lifetime_years")
+        # Check that loan tenor is less than or equal to project lifetime
+        if values.get("loan_tenor_years") is not None:
+            if values.get("loan_tenor_years", 25) > values.get("project_lifetime_years", 25):
+                raise ValueError("Loan tenor must be less than or equal to project lifetime")
+        return values
+
 class Location(BaseModel):
     longitude: Annotated[Optional[float], Field(ge=-180, le=180,
                                         title="Longitude",
@@ -190,13 +211,13 @@ class Location(BaseModel):
 
     @model_validator(mode="before")
     @classmethod
-    def empty_str_to_none(cls, values):
+    def zeroes_to_none(cls, values):
         """Convert empty strings or 0s to None"""
-        if values.get("address") == "":
+        if values.get("address") == "" or values.get("address") == "None":
             values["address"] = None
-        if values.get("longitude") == 0:
+        if values.get("longitude") == 0 or values.get("longitude") == "None":
             values["longitude"] = None
-        if values.get("latitude") == 0:
+        if values.get("latitude") == 0 or values.get("latitude") == "None":
             values["latitude"] = None
         return values
 

ui.py

@@ -56,9 +56,9 @@ def plot_revenues_costs(cashflow_model: pd.DataFrame) -> gr.Plot:
     df["Total Operating Costs"] = -df["Total_Operating_Costs_mn"] * 1000
     df["Total Revenues"] = df["Total_Revenues_mn"] * 1000
     df["Target Debt Service"] = df["Target_Debt_Service_mn"] * 1000
-    df["DCSR"] = df["CFADS_mn"] / df["Target_Debt_Service_mn"]
+    df["DSCR"] = df["CFADS_mn"] / df["Target_Debt_Service_mn"]
     # Round the values to 4 decimal places
-    df["DCSR"] = df["DCSR"].round(4)
+    df["DSCR"] = df["DSCR"].round(4)
 
     # Create a new dataframe with the required columns
     plot_df = df[
@@ -118,13 +118,13 @@ def plot_revenues_costs(cashflow_model: pd.DataFrame) -> gr.Plot:
         )
     )
 
-    # Add the DCSR line
+    # Add the DSCR line
     subfig.add_trace(
         go.Scatter(
             x=df["Period"],
-            y=df["DCSR"],
+            y=df["DSCR"],
             mode="lines+markers",
-            name="DCSR",
+            name="DSCR",
             line=dict(color="purple"),
         ),
         secondary_y=True,
@@ -140,10 +140,10 @@ def plot_revenues_costs(cashflow_model: pd.DataFrame) -> gr.Plot:
         ),
         margin=dict(l=50, r=50, t=130, b=50),
         barmode="overlay",
-        title="Total Revenues, Total Operating Costs, and DCSR",
+        title="Total Revenues, Total Operating Costs, and DSCR",
         xaxis_title="Year",
         yaxis_title="Amount",
-        yaxis2_title="DCSR",
+        yaxis2_title="DSCR",
     )
     return subfig
 
@@ -158,8 +158,9 @@ def trigger_lcoe(
     cost_of_equity,
     tax_rate,
     project_lifetime_years,
+    loan_tenor_years,
     degradation_rate,
-    dcsr,
+    dscr,
     financing_mode,
     request: gr.Request,
 ) -> Tuple[
@@ -181,9 +182,10 @@ def trigger_lcoe(
             cost_of_equity=cost_of_equity,
             tax_rate=tax_rate,
             project_lifetime_years=project_lifetime_years,
+            loan_tenor_years=loan_tenor_years,
             degradation_rate=degradation_rate,
-            dcsr=dcsr,
-            targetting_dcsr=(financing_mode == "Target DSCR"),
+            dscr=dscr,
+            targetting_dscr=(financing_mode == "Target DSCR"),
         )
 
         # Calculate the LCOE for the project
@@ -203,16 +205,16 @@ def trigger_lcoe(
             {
                 "lcoe": lcoe,
                 "post_tax_equity_irr": post_tax_equity_irr,
-                "debt_service_coverage_ratio": dcsr,
+                "debt_service_coverage_ratio": adjusted_assumptions.dscr,
                 "debt_pct_of_capital_cost": adjusted_assumptions.debt_pct_of_capital_cost,
                 "equity_pct_of_capital_cost": adjusted_assumptions.debt_pct_of_capital_cost,
-                "api_call": f"{request.request.url.scheme}://{request.request.url.netloc}/solarpv/?{urlencode(assumptions.model_dump())}",
+                "api_call": f"{request.request.url.scheme}://{request.request.url.netloc}/solarpv/lcoe?{urlencode(assumptions.model_dump())}",
             },
             plot_cashflow(cashflow_model),
             plot_revenues_costs(cashflow_model),
             adjusted_assumptions.debt_pct_of_capital_cost,
             adjusted_assumptions.equity_pct_of_capital_cost,
-            adjusted_assumptions.dcsr,
+            adjusted_assumptions.dscr,
             styled_model,
             gr.Markdown(f"## LCOE: {lcoe:,.2f}"),
         )
@@ -227,6 +229,13 @@ def update_equity_from_debt(debt_pct):
 
 def get_params(request: gr.Request) -> Dict:
     params = SolarPVAssumptions.model_validate(dict(request.query_params))
+    location_params = dict(longitude=request.query_params.get("longitude"), latitude=request.query_params.get("latitude"), address=request.query_params.get("address"))
+    for key in location_params:
+        if location_params[key] == "None":
+            location_params[key] = None
+        if location_params[key] is not None and key in ["latitude", "longitude"]:
+            location_params[key] = float(location_params[key])
+
     return {
         capacity_mw: params.capacity_mw,
         capacity_factor: params.capacity_factor,
@@ -236,11 +245,16 @@ def get_params(request: gr.Request) -> Dict:
         cost_of_equity: params.cost_of_equity,
         tax_rate: params.tax_rate,
         project_lifetime_years: params.project_lifetime_years,
+        loan_tenor_years: params.loan_tenor_years if params.loan_tenor_years else params.project_lifetime_years,
         degradation_rate: params.degradation_rate,
-        dcsr: params.dcsr,
+        debt_pct_of_capital_cost: params.debt_pct_of_capital_cost,
+        dscr: params.dscr,
         financing_mode: (
-            "Target DSCR" if params.targetting_dcsr else "Manual Debt/Equity Split"
+            "Target DSCR" if params.targetting_dscr else "Manual Debt/Equity Split"
         ),
+        latitude: location_params["latitude"],
+        longitude: location_params["longitude"],
+        address: location_params["address"],
     }
 
 
@@ -254,9 +268,13 @@ def get_share_url(
     cost_of_equity,
     tax_rate,
     project_lifetime_years,
+    loan_tenor_years,
     degradation_rate,
-    dcsr,
+    dscr,
     financing_mode,
+    latitude,
+    longitude,
+    address,
     request: gr.Request,
 ):
     params = {
@@ -269,9 +287,13 @@ def get_share_url(
         "cost_of_equity": cost_of_equity,
         "tax_rate": tax_rate,
         "project_lifetime_years": project_lifetime_years,
+        "loan_tenor_years": loan_tenor_years,
         "degradation_rate": degradation_rate,
-        "dcsr": dcsr,
-        "targetting_dcsr": financing_mode == "Target DSCR",
+        "dscr": dscr,
+        "targetting_dscr": financing_mode == "Target DSCR",
+        "latitude": latitude if latitude != 51.5074 else None,
+        "longitude": longitude if longitude != -0.1278 else None,
+        "address": address if address else None,
     }
     base_url = "?"
     return gr.Button(link=base_url + urlencode(params))
@@ -330,6 +352,14 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
                     maximum=0.6,
                     step=0.01,
                 )
+                degradation_rate = gr.Slider(
+                    value=0.005,
+                    label="Degradation Rate (%)",
+                    minimum=0,
+                    maximum=0.05,
+                    step=0.005,
+                )
+            with gr.Row():
                 project_lifetime_years = gr.Slider(
                     value=25,
                     label="Project Lifetime (years)",
@@ -337,19 +367,19 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
                     maximum=50,
                     step=1,
                 )
-                degradation_rate = gr.Slider(
-                    value=0.005,
-                    label="Degradation Rate (%)",
-                    minimum=0,
-                    maximum=0.05,
-                    step=0.005,
+                loan_tenor_years = gr.Slider(
+                    value=25,
+                    label="Loan Tenor (years)",
+                    minimum=5,
+                    maximum=50,
+                    step=1,
                 )
             with gr.Row():
                 capital_expenditure_per_kw = gr.Slider(
                     value=670,
                     label="Capital expenditure ($/kW)",
                     minimum=1e2,
-                    maximum=1e3,
+                    maximum=5e3,
                     step=10,
                 )
                 o_m_cost_pct_of_capital_cost = gr.Slider(
@@ -398,7 +428,7 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
                         interactive=False,
                         precision=2,
                     )
-                    dcsr = gr.Slider(
+                    dscr = gr.Slider(
                         value=1.3,
                         label="Debt Service Coverage Ratio",
                         minimum=1,
@@ -441,8 +471,9 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
         cost_of_equity,
         tax_rate,
         project_lifetime_years,
+        loan_tenor_years,
         degradation_rate,
-        dcsr,
+        dscr,
         financing_mode,
     ]
 
@@ -457,7 +488,7 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
             revenue_cost_chart,
             debt_pct_of_capital_cost,
             equity_pct_of_capital_cost,
-            dcsr,
+            dscr,
             model_output,
             lcoe_result,
         ],
@@ -465,13 +496,28 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
 
     json_output.change(
         fn=get_share_url,
-        inputs=input_components,
+        inputs=input_components
+        + [
+            latitude,
+            longitude,
+            address,
+        ],
         outputs=share_url,
         trigger_mode="always_last",
     )
 
     # Load URL parameters into assumptions and then trigger the process_inputs function
-    interface.load(get_params, None, input_components, trigger_mode="always_last").then(
+    interface.load(
+        get_params,
+        None,
+        input_components
+        + [
+            latitude,
+            longitude,
+            address,
+        ],
+        trigger_mode="always_last",
+    ).then(
         trigger_lcoe,
         inputs=input_components,
         outputs=[
@@ -480,7 +526,7 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
             revenue_cost_chart,
             debt_pct_of_capital_cost,
             equity_pct_of_capital_cost,
-            dcsr,
+            dscr,
             model_output,
             lcoe_result,
         ],
@@ -489,19 +535,19 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
     def toggle_financing_inputs(choice):
         if choice == "Target DSCR":
             return {
-                dcsr: gr.update(interactive=True),
+                dscr: gr.update(interactive=True),
                 debt_pct_of_capital_cost: gr.update(interactive=False),
             }
         else:
             return {
-                dcsr: gr.update(interactive=False),
+                dscr: gr.update(interactive=False),
                 debt_pct_of_capital_cost: gr.update(interactive=True),
             }
 
     financing_mode.change(
         fn=toggle_financing_inputs,
         inputs=[financing_mode],
-        outputs=[dcsr, debt_pct_of_capital_cost, equity_pct_of_capital_cost],
+        outputs=[dscr, debt_pct_of_capital_cost, equity_pct_of_capital_cost],
     )
 
     # Add debt percentage change listener
@@ -525,7 +571,8 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
             pv_location.address,
         )
 
-    gr.on([estimate_capacity_factor.click, interface.load],
+    gr.on(
+        [estimate_capacity_factor.click, interface.load],
         fn=get_capacity_factor_from_location,
         inputs=[latitude, longitude, address],
         outputs=[capacity_factor, latitude, longitude, address],
@@ -533,7 +580,9 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
 
     def update_location_plot(latitude, longitude, address):
         return px.scatter_mapbox(
-            pd.DataFrame({"latitude": [latitude], "longitude": [longitude], "address": [address]}),
+            pd.DataFrame(
+                {"latitude": [latitude], "longitude": [longitude], "address": [address]}
+            ),
             lat="latitude",
             lon="longitude",
             mapbox_style="carto-darkmatter",
@@ -544,7 +593,7 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
             mapbox=dict(
                 center=dict(lat=latitude, lon=longitude),
                 zoom=10,
-            )
+            ),
         )
 
     gr.on(
@@ -560,3 +609,15 @@ with gr.Blocks(theme="citrus", title="Renewable LCOE API") as interface:
         inputs=[],
         outputs=[latitude, longitude],
     )
+
+    # If user changes the project lifetime, set the maximum loan tenor to the project lifetime
+    def update_loan_tenor(project_lifetime_years, loan_tenor_years):
+        if project_lifetime_years < loan_tenor_years:
+            return gr.Slider(value=project_lifetime_years, maximum=project_lifetime_years)
+        return gr.Slider(maximum=project_lifetime_years)
+
+    project_lifetime_years.change(
+        fn=update_loan_tenor,
+        inputs=[project_lifetime_years, loan_tenor_years],
+        outputs=[loan_tenor_years],
+    )