In [5]:

```
#Variable Declaration:
P = 90000 #initial cost of transformer(Rs)
n = 20 #20 years
S = 10000 #Salvage value(Rs)
#Calculation:
D = (P-S)/n #Annual depreciation charge(Rs)
print "The annual depreciation charge is Rs",D
```

In [6]:

```
from __future__ import division
#Variable declaration
P = 200000 #Initial cost of transformer(Rs)
S = 10000 #Salvage value of transformer(Rs)
n = 20 #Useful life(years)
r = 0.08 #annual interest rate(%)
#Calculation:
q = (P-S)*r/(((1+r)**n)-1) #Annual payment(Rs)
#Results:
print "The annual amount to be saved is Rs",round(q)
```

In [7]:

```
#Variable declaration:
P = 1560000 #Initial cost of equipment(Rs)
S = 60000 #salvage value of equipment(Rs)
n = 25 #useful life(years)
t = 20 #years
#Calculation:
#(i) Straight line method:
D1 = (P-S)/n #Annual depreciation(Rs)
V1 = P-D1*t #Value of equipment after 't' years
#(ii)Diminishing value method:
D2 = 1-(S/P)**(1/n) #Annual unit depreciation(Rs)
V2 = P*(1-round(D2,3))**t #Value of equipment after 't' years
#(iii)Sinking fund method:
r = 0.05 #rate of interest
q = (P-S)*(r/((1+r)**n-1)) #Annual deposit in the sinking fund(Rs)
q1 = 31433*(((1+r)**20-1)/r) #Sinking fund at the end of 20 years(Rs)
V = P-q1 #Value of plant after 20 years(Rs)
#Results:
print "The depreciated values using:"
print "(i) Straight line method: Rs",V1
print "(ii)Diminishing value method Rs:",round(V2)
print "(iii)Sinking fund method: Rs",round(V)
```

In [8]:

```
#Variable declaration:
M = 50000 #Max demand(kW)
CC = 95*10**6 #Capital cost(Rs)
LF = 0.4 #annual load factor
C1 = 9*10**6 #Annual cost of fuel and oil(Rs)
C2 = 7.5*10**6 #taxes wages salaries etc(Rs)
i = 12 #interest & depreciation(%)
#Calculation:
E = M*LF*8760 #units generated(kWh/year)
AFC = i*CC/100 #Annual fixed charges(Rs)
T = C1+C2 #Total annual running charges(Rs)
TAC = AFC+T #Total annual charges(Rs)
c = TAC/E #cost per unit(Rs)
#Results:
print "Cost per unit generated = ",round(c,2)*100,"paise"
```

In [9]:

```
#Variable declaration:
C = 50000 #Installed capacity(kW)
E = 220*10**6 #units generated(kWh/year)
AFC1 = 160 #annual fixed charges per kW of C(Rs/kW)
RC = 0.04 #running charges(Rs)
#Calculation:
AFC = AFC1*C #annual fixed charges(Rs)
ARC = RC*E #annual running charges(Rs)
c = (AFC+ARC)/E #cost per unit(Rs)
#Results:
print "Cost per unit generated is ",round(c,4)*100,"paise"
```

In [10]:

```
from __future__ import division
#Variable declaration:
C = 160000 #cost of plant(Rs)
r = 12 #annual fixed charges(%)
r1 = 5 #interest(%)
r2 = 5 #depreciation(%)
r3 = 2 #taxes(%)
M = 100 #max demand(kW)
#Calculation:
AFC = C*r/100 #annual fixed charges(Rs)
#(i)when load factor is 100%
E1 = M*1*8760 #kWh/year
c1 = AFC/E1 #Rs
#(i)when load factor is 50%
E2 = M*0.5*8760 #kWh/year
c2 = AFC/E2 #Rs
#Results:
print "Fixed charges when:"
print "(i) load factor is 100% :",round(c1*100,2),"paise"
print "(ii)load factor is 50% :",round(c2*100,2),"paise"
```

In [11]:

```
#Variable declaration:
PC = 50 #plant capacity(MW)
LF = 0.4 #annual load factor
C1 = 1.2*10**7 #capital cost(Rs)
C2 = 4*10**5 #annual cost of wages, taxation etc.(Rs)
C3 = 1.0 #cost of fuel,lubrication, maintenance etc.(paise/kWh)
r1 = 5 #interest rate(%)
r2 = 6 #depreciation(%)
#Calculation:
T1 = (C1*(r1+r2)/100)+C2 #Total annual fixed charges(Rs)
E = PC*10**3*LF*8760 #units generated(kWh/year)
C4 = E*C3/100 #Cost of fuel, lubrication etc.(Rs)
T = T1+C4 #total annual charges(Rs)
c = T/E #generating cost(Rs/kWh)
#Results:
print "Cost per kWh is ",round(c*100),"paise"
```

In [12]:

```
#Variable declaration:
PC = 300 #plant capacity(MW)
CF = 0.5 #capacity factor
LF = 0.6 #annual load factor
C1 = 9*10**7 #Annual cost of fuel, oil etc(Rs)
C2 = 10**9 #capital cost(Rs)
r1 = 10 #annual interest and depreciation(%)
#Calculation:
L = CF*PC #avg load(MW)
M = L/LF #max demand(MW)
RC = PC-M #Reserve capacity(MW)
TC = C1+C2*r1/100 #total cost(Rs)
E = L*10**3*8760 #units generated(kWh/year)
c = TC/E #cost per kWh
#Results:
print "The minimum reserve capacity of the station is",RC,"MW"
print "Cost per kWh generated is ",round(c*100),"paise"
```

In [13]:

```
from __future__ import division
#Variable declaration:
PC = 50 #plant capacity(MW)
CC = 1000 #capital cost(Rs/kW)
r1 = 10 #annual depreciation charges(%)
r2 = 20 #part of salaries, maitenance to fixed charges(%)
M = 40 #max demand(MW)
LF = 0.60 #load factor
C1 = 700000 #Annual cost of salaries, maintenance charges etc.(Rs)
R1 = 1 #royalty(Re/(kW*year))
R2 = 0.01 #royalty paid for using the river water for generation(Re/kWh)
#Calculation:
#for annual fixed cost
E = M*10**3*LF*8760 #kWh/year
C = CC*PC*10**3 #capital cost(Rs)
T1 = r1*C/100+r2*C1/100 #total annual fixed charges(Rs)
C2 = T1/(M*10**3)+R1 #Cost per kW(Rs)
#for running cost:
C3 = ((1-r2/100)*C1)/E+R2 #Cost per kW(Rs)
#Results:
print "Total generation cost in two part form is given by:"
print "Rs (",C2,"* kW +",round(C3,4),"* kWh)"
```

In [14]:

```
#Variable declaration:
M = 60 #plant capacity(MW)
LF = 0.5 #load factor
C1 = 5*10**6 #capital cost of building and equipment(Rs)
C2 = 900000 #annual cost of fuel,oil,taxation and wages(Rs)
r1 = 10 #interest and depreciation(%)
C3 = 5000000 #annual cost of organisation and
#interest on cost of site etc.
#Calculation:
E = M*10**3*LF*8760 #kWh/year
a = C3 #Rs
T2 = r1*C3/100 #Annual semi-fixed cost(Rs)
b = T2/(M*10**3) #cost per kW
c = C2/E #cost per kWh
#Results:
print "The required values are:"
print "a = Rs",a,", b = ",round(b,2),", c = Re",round(c,4)
```

In [15]:

```
#Variable declaration:
PC = 100 #installed capacity(kW)
CC = 3000 #plant cost(Rs/kW of PC)
r1 = 5 #interest(%)
r2 = 2 #depreciation(2%)
r3 = 2 #operation & maintenance(%)
r4 = 1.5 #insurance, rent(%)
r = 12.5 #losses in transmission and distribution(%)
DF = 1.25 #diversity factor
LF = 0.4 #load factor
M = 0.8*PC #max demand(kW)
#Calculation:
L = M*LF #avg demand(kW)
C1 = CC*PC #Capital cost(Rs)
T1 = (r1+r2)*C1/100 #annual fixed charges(Rs)
T11 = T1/(DF*M) #annual fixed charges(Rs/kW)
RC = C1*(r3+r4)/100 #annual running charges(Rs)
E = L*8760 #kWh/year
E1 = E*(1-r/100) #units reaching the consumer(kWh)
RC1 = RC/E1 #annual running charges(Rs/kWh)
T = T1+RC #total charges(Rs)
C2 = T/E1 #cost per kWh(Rs)
#Results:
print "Total generation cost in two part form is given by:"
print "Rs (",T11,"* kW +",round(RC1,3),"* kWh)"
print "Overall cost of generation per kWh is ",round(C2*100,1),"paise"
```

In [16]:

```
#variable declaration:
M = 1000 #max demand(kW)
LF = 0.5 #load factor
#for (i)a private oil engine generating plant:
CC1 = 12*10**5 #capital cost(Rs)
c1 = 0.005 #Cost of repair and maintenance(Rs/kWh)
c2 = 1600 #Cost of fuel(Rs/1000kg)
r1 = 10 #Interest and depreciation (%)
w = 0.3 #fuel consumption(kg/kWh)
c3 = 50000 #wages(Rs)
#for (i)Public supply company:
#Rs 150 per kW of maximum demand plus 15 paise per kWh
#Calculation:
E = M*LF*8760 #kWh/year
#for(i) Private oil engine generating plant:
W = w*E #annual fuel consumption(kg)
C1= W*c2/1000 #cost of fuel(Rs)
T1 = C1+c1*E+r1*CC1/100+c3 #total annual cost(Rs)
#for(ii)Public supply company:
T2 = 150*M+.15*E #total annual cost(Rs)
#Results:
print "(i)For Private oil engine generating plant,"
print " total annual charges is Rs",T1
print "(ii)Public supply company, total annual charges is Rs",T2
```

In [17]:

```
from __future__ import division
#Variable declaration:
LF = 0.3 #load factor
M = 100 #max demand(MW)
#steam:
cc1 = 1250 # Capital cost/kW installed(Rs)
r11 = 12 # Interest and depreciation(%)
c11 = 5 # Operating cost/kWh, paise
tc11 = 0 # Transmission cost/kWh
#hydro:
cc2 = 2500 # Capital cost/kW installed(Rs)
r21 = 10 # Interest and depreciation(%)
c21 = 1.5 # Operating cost/kWh,paise
tc21 = 0.2 # Transmission cost/kWh,paise
#Calculation:
E = M*LF*8760*10**3 #kWh/year
#(i)steam station in conjunction with a hydro station:
Eh = 100*10**6 #units supplied by hydro station(kWh)
Es = E-Eh #units supplied by steam station(kWh)
Pmh = 40 #max o/p of hydro stn.(MW)
Pms = 60 #max o/p of steam stn(MW)
#(i)(a)for steam station:
Cs1 = cc1*Pms*10**3 #capital cost(Rs)
Ts1 = r11*Cs1/100+c11*Es/100+0 #total cost(Rs)
# (b)for hydro station:
Ch1 = cc2*Pmh*10**3 #capital cost(Rs)
Th1 = r21*Ch1/100+c21*Eh/100+tc21*Eh/100 #total cost(Rs)
Ta = Ts1+Th1 #total annual cost(Rs)
OC1 = Ta/E #kWh
#(ii)Steam station:
Pm2 = 100*10**3 #max o/p of steam plant(kW)
Cs2 = cc1*Pm2 #capital cost(Rs)
Ts2 = (Cs2*r11/100)+c11*E/100 #Rs
OC2 = Ts2/E #overall cost(Rs)
#(iii)Hydro station:
Ch3 = cc2*Pm2 #capital cost(Rs)
Th3 = Ch3*r21/100+c21*E/100 #Rs
OC3 = Th3/E+tc21/100 ##overall cost(Rs)
#Results:
print "(i)steam station in conjunction with a hydro station:"
print " for steam stn., overall cost is ",round(OC1*100,2),"paise"
print "(ii) Steam station, overall cost is ",round(OC2*100,2),"paise"
print "(ii) Hydro station, overall cost is ",round(OC3*100,2),"paise"
```

In [18]:

```
from __future__ import division
from sympy import *
#Variable declaration:
M = 150*10**3 #maximum demand(kW)
#Steam plant:
cc1 = 1600 #Rs/kW
oc1 = 0.06 #operating cost(Rs/kWh)
r1 = 7 #interest(%)
#Hydro plant:
cc2 = 3000 #Rs/kW
oc2 = 0.03 #operating cost(Rs/kWh)
r2 = 7 #interest(%)
#Calculation:
x = symbols('x') #total no. of units generated
#for steam plant:
cs = cc1*M #capital cost(Rs)
Ts = r1*cs/(x*100)+oc1 #total cost(Rs)
Ts1 = Ts #Rs/kWh
#for hydro plant:
ch = cc2*M #capital cost(Rs)
Th = r2*ch/(100*x)+oc2 #total cost(Rs)
Th1 = Th #Rs/kWh
L = solve(Ts1-Th1,x)
LF = (L[0])/(M*8760)
print "Load factor is ",round(LF*100,1),"%"
```

In [19]:

```
from __future__ import division
from sympy import *
#Variable declaration:
Eo = 40*10**6 #units needed to generate
#Hydro Steam
cc1 = 2100; cc2 = 1200 #Capital cost(Rs/kW)
rc1 = 3.2; rc2 = 5 #Running cost(paise/kWh)
r1 = 7.5; r2 = 9 #Interest & depreciation(%)
RC1 = 33; RC2 = 25 #Reserve capacity(%)
#Calculation:
#Let x kW be the maximum demand.
#Let y be the annual load factor at which cost/unit
#of steam and hydro stations is the same.
x,y = symbols('x y')
E = x*y*8760 #units generated per annum(kWh)
C2 = x+RC2*x/100 #installed capacity of steam station(kW)
C1 = x+RC1*x/100 #installed capacity of hydro station(kW)
#steam station:
CC2 = cc2*C2 #capital cost(Rs)
OC2 = (r2*CC2/100+rc2*E/100)/E #Overall cost/kWh
#hydro station:
CC1 = cc1*C1 #capital cost(Rs)
OC1 = (r1*CC1/100+rc1*E/100)/E #Overall cost/kWh
LF = solve(OC1-OC2,y)[0] #load factor
E2 = 8760*x*LF #kWh
M = solve(E2-Eo,x)[0] #max. demand(kW)
C = (135*M + 438*M*LF) #cost of generation(Rs)
#Results
print "Load factor is ",round(LF*100,2),"%"
print "Required cost of generation is Rs (",round(C/10**6,1),"* 10**6 )"
```

In [14]:

```
from __future__ import division
from sympy import *
#Variable declaration:
#Let x = Installed capacity of station B in kW
#y = Hours of operation of station B
x,y = symbols('x y')
M = 50000 #max demand(kW)
#Calculation:
PCa = M-x #installed capacity of stationA(kW)
Eb = (1/2)*x*(8760*x/M) #Units generated/annum by station B
Ea = (1/2)*8760*M-Eb #Units generated/annum by station A
Cb = 50000+50*x+0.03*Eb #Rs
Ca = 75000+80*(50000-x)+0.02*Ea #Rs
C = Ca+Cb #total operating cost(Rs)
#After differentiating C w.r.t x, we get C1 as
C1 = -30+0.00174*x
x1 = solve(C1,x)[0]
PCb = x1 #kW
PCa = M-PCb #kW
t = 8760*PCb/M #hours of operation of station B
#Results:
print "Installed capacity of station A is ",round(PCa),"MW"
print "Installed capacity of station B is ",round(PCb),"MW"
print "No. of hours of operation of plant B is",round(t/10)*10,"hrs"
```