part 1: overview of cogeneration and its status in asia - Fire

Sample case study in a pulp and paper mill 111
2.3 Calculation of Costs and Benefits
After evaluating the technical potential of the alternative cogeneration systems, the different
sources of revenues and expenses of the systems are determined so that the evaluation of
the economic potential of each system could be followed.
Table 2.7 Summary of the results for the gas turbine
Thermal Matching
5,000 kg/hr 13,000 kg/hr
Power Generating Capacity, kW 2,493 6,482
Power Generation, MWh/year 18,673 48,550
Excess(+)/Deficit(-) Power, MWh/year 5,958 35,835
Excess(+)/Deficit(-) Heat, TJ/year -55 111
Fuel Consumption, TJ/year 269 699
Power Matching
1,500 kW 2,430 kW
Heat Generating Capacity, kJ/kg 3,008 4,873
Heat Generation, TJ/year 62 101
Excess(+)/Deficit(-) Heat, TJ/year -96 -57
Excess(+)/Deficit(-) Power, MWh/year -1,480 5,485
Fuel Consumption, TJ/year 162 262
2.3.1 Costs
(a) Total installation cost
The installation cost of each cogeneration system can be roughly estimated by the formula
taken from the report on “Industrial and Commercial Cogeneration”, Office of Technology
Assessment, Washington D.C., U.S.A.:
• Steam Turbine (Oil-Fired):
C = [962.761- (9.119 x10 -3 x M) - (1.314 x 10 -7 x M 2 ) + (2.782 x 10 -11 x M 3 )] x M x E
• Diesel Engine:
C = [915.14 - (6.531 x 10 -2 x M) + (4.56 x 10 -6 x M 2 ) - (1.424 x 10 -10 x M 3 )] x M x E
Where, C = installation cost, Peso
M = installed capacity, kW
E = peso - dollar exchange rate, assumed 26 Peso/$ in 1996
(b) Operating costs
The operating costs in this case study include:
• Fuel Costs: cost of fuel consumed by the cogeneration unit.
• Operating and Maintenance Costs: These are taken as 2.5 per cent of the total installation
cost of the cogeneration unit.