|
Bagasse-based Cogeneration
Introduction
In simple terms, cogeneration is the process
of using a single fuel to produce more than one form of energy
in sequence. Cogeneration of steam and electricity can significantly
increase the overall efficiencies of fuel utilization in process
industries. A minimum condition for cogeneration is the simultaneous
requirement of heat and electricity in a favourable ratio,
which is well fulfilled in the sugar industry. The thermodynamics
of electricity production necessitates the rejection of a
large quantity of heat to a lower temperature sink. In normal
electricity generation plants, this heat rejection takes place
in condensers where up to 70% of heat in steam is rejected
to the atmosphere. In cogeneration mode, however, the heat
is not wasted and is instead used to meet process-heating
requirement. The overall efficiency of fuel utilization can
thus be increased to 60% or even higher in some cases. Capacity
of cogeneration projects can range from a few kilowatts to
several megawatts of electricity generation a long with simultaneous
production of heat ranging from less than a hundred kW th
(kilowatts thermal) to many MW th (megawatts thermal).
Potential
The potential for cogeneration projects is estimated at 3500
MW of additional power generation from the country's existing
functional sugar mills.
Achievements
India, today, is perhaps the world leader in the implementation
of modern cogeneration projects in sugar mills. The achievements
merit attention not only because of the additional grid-connected
power generation capacity but also because of the large number
of sugar mills, which have implemented these projects. This
is noteworthy because of the diverse nature of operating conditions
across these mills. An additional power generation capacity
of 447 MW has been commissioned in 58 sugar mills as of March
2005. A further capacity addition of about 313 MW in 34 sugar
mills is reported to be under implementation. A state-wise
distribution of the commissioned and 'under implementation'
capacity is given in Table
State-wise distribution of commissioned
and 'under implementation' cogeneration capacity, as on 31
March 2005.
| State |
Commissioned |
Uner Implementation |
| Number of projects |
Capacity (MW) |
Number of projects |
Capacity (MW) |
| Andhra Pradesh |
12 |
73.05 |
7 |
55.71 |
| Gujarat |
- |
- |
- |
- |
| Haryana |
1 |
2.00 |
- |
- |
| Karnataka |
10 |
115.98 |
9 |
94.66 |
| Maharashtra |
8 |
32.50 |
7 |
69.80 |
| Punjab |
2 |
12.00 |
- |
- |
| Tamil Nadu |
15 |
138.50 |
3 |
28.50 |
| Uttar Pradesh |
10 |
73.00 |
8 |
64.30 |
| Total |
58 |
447.03 |
34 |
312.97 |
Technology and equipment
The technology for bagasse-based cogeneration has become
fairly well established in the country. The main equipment
required for these projects comprise high-pressure bagasse-fired
boilers, steam turbines, and grid-inter-phasing system. All
these equipment are manufactured indigenously. An extremely
competent and experienced group of technical professionals
capable of providing comprehensive project and operational
services has also been developed in the country to support
bagasse-based cogeneration projects.
Costs
The capital costs of installed bagassed-based cogeneration
projects in sugar mills are known to range between Rs 3 crores/MW
and Rs 4 crores/MW. It has been seen that for a typical sugar
mill having an average crushing season of 160 days, investments
for additional power generation through cogeneration will
turn out to be beneficial in the long term.
Financial Incentives
The present levels of interest subsidy offered by the MNES
for various categories of bagasse-based cogeneration projects
are detailed in Table
Interest subsidy for different categories
of bagasse-based cogeneration projects
| Category of projects |
Pressure configuration |
Interest subsidy |
| projects by cooperative/public/joint
sector sugar mills |
40 bar and above
60 bar and above
80 bar and above
100 bar and above |
3%
4%
5%
6% |
Projects in independent
power
producer mode in cooperative/
public/joint sector sugar mills |
60 bar and above
80 bar and above
100 bar and above |
2%
3%
4% |
| Projects by private sector
sugar mills |
60 bar and above
80 bar and above
100 bar and above |
1%
2%
3% |
However, these are subject to change from time to time and
the latest information on the scheme of incentives can be
obtained from the MNES website:
www.mnes.nic.in
Main Application: Energy
Contact:
Ministry of Non-Conventonal Energy Sources,
Govt. of India
Block-14, CGO Complex, Lodi Road
New Delhi – 110 003
Tel: 91 11 2436 0707/ 2436 0404
Fax: 91 11 2436 1298
|
