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

170 Part3: Summary of country studies – Bangladesh and Viet Nam
IRR (%) 31.7 17.1 25.2 27.9
NPV (million VND) 26,224 8,897 36,288 42,189
Total installation cost (million VND) 23,952 68,831 57,552 52,438
Pay back period (year) 6 13 7 6
The average power-to-heat ratio is 0.275, for which steam turbine cogeneration seems
suitable. Four alternatives are considered for the analysis, including steam turbine using coal,
reciprocating engine using fuel oil, and gas turbine using natural gas. The results of the
analysis for this company are shown in Table 4.5.
Alternative 1 seems to be the most attractive option since its IRR and investment cost are the
lowest among the four alternatives considered. The main advantage of this alternative is
derived from the use of coal, which is a cheap fuel. However, it can satisfy a little more than
30 per cent of the company’s electricity demand. Alternative 2 can take care of all the power
and heat demands of the factory but its IRR is the lowest and its investment cost is the
highest among the four alternatives.
Alternative 3 is also very attractive but its IRR is lower and investment cost is higher than
those for the first alternative.
The alternative 4 can also meet all the energy needs of the site and has a fairly high IRR but
natural gas is presently not available at the site.
4.3.4 Paper mill “D”
This is a big paper mill in Dông Nai province, with a capacity to produce 170 tons of paper per
day. The factory has a condensing steam turbine power generator but it is not used. The
company functions during 3 shifts per day, 300 days per year. It is presently connected to the
national grid to take care of all its power needs. The power supply reliability is essential for
the company for its production process. Self-generation with interconnection to the national
grid could be a good solution for the company in the existing difficult situation of the power
sector.
Analysis of the electricity and steam consumption data allows to conclude the following:
• Total Annual Electricity Consumption: 48,645 MWh
• Maximum Electricity Demand: 7.66 MW
• Minimum Electricity Demand: 3.84 MW
• Total Annual Fuel Oil Consumption: 13.8 million litres
• Total Annual Steam Use: 164,721 tons
• Maximum Steam Demand: 29.1 tons/hr
• Minimum Steam Demand: 11.1 ton/hr
With an average power-to-heat ratio of 0.39 for the factory, the steam turbine cogeneration
configuration seems the most suitable. The analysis for the Paper Company “D” was done
with three configurations, including steam turbine, reciprocating engine and gas turbine, in
order to make a comparison. The results of the analysis for this company are shown in Table
4.6.
Among the above four alternatives, Alternative 2 seems to be the best since it gives a high
IRR and taking fuel supply availability into consideration. The alternative 4 with natural gas as
fuel seems to be the most attractive option but natural gas is not presently available at the
site.