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

Summary of country study – Bangladesh 147
What if the electricity price escalates faster?
Internal Rate of Return (IRR)
50%
45%
40%
35%
30%
6% 7% 8% 9% 10% 11% 12% 13%
Escalation Rate of Electricity Price
From the sensitivity analysis of the potential cogeneration alternatives for the vegetable oil
refinery, the reciprocating engine power match option meeting power requirement of 520 kW
is found to be the most suitable cogeneration system. It represents an initial investment of 22
Million Taka and leads to an internal rate of return of 40.3 per cent.
3.3.3 Textile spinning mill
This factory operates 24 hours a day and 350 days a year. Natural gas is used in boiler to
generate steam that is required for the process. The production is greatly affected by any
fluctuations or micro-cuts in the power supply.
Analysis of the monthly electricity and steam consumption data of 1997 led to the following:
• Total Electricity Consumption in 1997: 20,096 MWh
• Maximum Electricity Demand: 2,500 kW
• Minimum Electricity Demand: 2,350 kW
• Total Thermal Energy Consumption in 1997: 66 TJ
• Maximum Steam Demand: 3.520 ton/hr
• Minimum Steam Demand: 3.225 ton/hr
The power-to-heat ratio of the site was estimated as 1.1 for 1997. Typical cogeneration
system for this site would be based on reciprocating engine. However, steam turbine and
gas turbine cogeneration systems were also considered as potential alternatives. Results of
the feasibility study are summarized in Table 3.7.
As expected, the steam turbine option is not suitable: (i) with steam turbine thermal match
(STTM), less than 10 per cent of the power requirement is met; (ii) with steam turbine power
match (STPM), 770 per cent excess heat is generated.
With the reciprocating engine thermal match (RETM) option, 62 per cent excess power is
generated. The project profitability will depend on the buy-back rate. This may not be a good
option as the purpose is not to earn from electricity sale. Reciprocating engine power match
(REPM) option seems feasible as almost all the power requirement can be met though the
heat generated is largely inadequate to meet the demand. An auxiliary boiler will be
necessary to make up for over 65 per cent shortfall in the heat supply.
REPM
GTPM
GTTM