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Add forwarded losses and fix NPV per #180 #182

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merged 2 commits into from
Jan 10, 2024
Merged

Add forwarded losses and fix NPV per #180 #182

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8ca0bec
add forwarded losses and fix NPV per #180
yalinli2 Jan 9, 2024
c36cdf6
optimize and minor changes
Jan 10, 2024
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30 changes: 17 additions & 13 deletions biosteam/_tea.py
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@
'Tax [MM$]',
'Incentives [MM$]',
'Taxed earnings [MM$]',
'Forwarded losses [MM$]',
'Net earnings [MM$]',
'Cash flow [MM$]',
'Discount factor',
Expand Down Expand Up @@ -174,7 +175,7 @@ def taxable_and_nontaxable_cashflows(
finance_fraction,
start, years,
lang_factor,
pay_interest_during_construction,
accumulate_interest_during_construction,
):
# Cash flow data and parameters
# C_FC: Fixed capital
Expand All @@ -199,7 +200,7 @@ def taxable_and_nontaxable_cashflows(
interest = finance_interest
years = finance_years
Loan[:start] = loan = finance_fraction*(C_FC[:start])
if pay_interest_during_construction:
if accumulate_interest_during_construction:
loan_principal = loan_principal_with_interest(loan, interest)
else:
loan_principal = loan.sum()
Expand Down Expand Up @@ -321,7 +322,7 @@ class TEA:
'_startup_schedule', '_operating_days',
'_duration', '_depreciation_key', '_depreciation',
'_years', '_duration', '_start', 'IRR', '_IRR', '_sales',
'_duration_array_cache', 'pay_interest_during_construction')
'_duration_array_cache', 'accumulate_interest_during_construction')

#: Available depreciation schedules. Defaults include modified
#: accelerated cost recovery system from U.S. IRS publication 946 (MACRS),
Expand Down Expand Up @@ -399,7 +400,7 @@ def __init__(self, system: System, IRR: float, duration: tuple[int, int],
startup_months: float, startup_FOCfrac: float, startup_VOCfrac: float,
startup_salesfrac: float, WC_over_FCI: float, finance_interest: float,
finance_years: int, finance_fraction: float,
pay_interest_during_construction: bool=False):
accumulate_interest_during_construction: bool=False):
#: System being evaluated.
self.system: System = system

Expand Down Expand Up @@ -444,8 +445,8 @@ def __init__(self, system: System, IRR: float, duration: tuple[int, int],
#: Guess cost for solve_price method
self._sales: float = 0

#: Whether to pay interest before operation or to accumulate interest during construction
self.pay_interest_during_construction = pay_interest_during_construction
#: Whether to immediately pay interest before operation or to accumulate interest during construction
self.accumulate_interest_during_construction = accumulate_interest_during_construction

#: For convenience, set a TEA attribute for the system
system._TEA = self
Expand Down Expand Up @@ -722,6 +723,7 @@ def get_cashflow_table(self):
# T: Tax
# I: Incentives
# TE: Taxed earnings
# FL: Forwarded losses
# NE: Net earnings
# CF: Cash flow
# DF: Discount factor
Expand All @@ -735,7 +737,7 @@ def get_cashflow_table(self):
VOC = self.VOC
sales = self.sales
length = start + years
C_D, C_FC, C_WC, D, L, LI, LP, LPl, C, S, T, I, TE, NE, CF, DF, NPV, CNPV = data = np.zeros((18, length))
C_D, C_FC, C_WC, D, L, LI, LP, LPl, C, S, T, I, TE, FL, NE, CF, DF, NPV, CNPV = data = np.zeros((19, length))
self._fill_depreciation_array(D, start, years, TDC)
w0 = self._startup_time
w1 = 1. - w0
Expand All @@ -759,14 +761,14 @@ def get_cashflow_table(self):
years = self.finance_years
end = start + years
L[:start] = loan = self.finance_fraction*(C_FC[:start])
pay_interest_during_construction = self.pay_interest_during_construction
if pay_interest_during_construction:
accumulate_interest_during_construction = self.accumulate_interest_during_construction
if accumulate_interest_during_construction:
initial_loan_principal = loan_principal_with_interest(loan, interest)
else:
initial_loan_principal = loan.sum()
LP[start:end] = solve_payment(initial_loan_principal, interest, years)
loan_principal = 0
if pay_interest_during_construction:
if accumulate_interest_during_construction:
for i in range(end):
LI[i] = li = (loan_principal + L[i]) * interest
LPl[i] = loan_principal = loan_principal - LP[i] + li + L[i]
Expand All @@ -781,17 +783,19 @@ def get_cashflow_table(self):
LI[:start] = L[:start] * interest # Interest still needs to be payed

taxable_cashflow = S - C - D - LP
if pay_interest_during_construction: taxable_cashflow[:start] -= LI[:start]
nontaxable_cashflow = D + L - C_FC - C_WC
if not accumulate_interest_during_construction:
nontaxable_cashflow[:start] -= LI[:start] # Subtract the interest during construction from NPV
else:
taxable_cashflow = S - C - D
nontaxable_cashflow = D - C_FC - C_WC
TE[:] = taxable_earnings_with_fowarded_losses(taxable_cashflow)
FL[:] = (taxable_cashflow - TE).cumsum()
self._fill_tax_and_incentives(I, taxable_cashflow, nontaxable_cashflow, T, D)
NE[:] = taxable_cashflow + I - T
CF[:] = NE + nontaxable_cashflow
DF[:] = 1/(1.+self.IRR)**self._get_duration_array()
NPV[:] = CF*DF
NPV[:] = CF * DF
CNPV[:] = NPV.cumsum()
DF *= 1e6
data /= 1e6
Expand Down Expand Up @@ -849,7 +853,7 @@ def _taxable_nontaxable_depreciation_cashflows(self):
self.finance_fraction,
start, years,
self.lang_factor,
self.pay_interest_during_construction,
self.accumulate_interest_during_construction,
),
D
)
Expand Down
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