Dr. J. R. Meshram*
Gargi Malik**
Think
of a sugar mill, not only producing sugar but also generating power as a
by-product. Bagasse, a residue of crushed sugarcane used in sugar mills is the principal
fuel used to raise steam in sugar mills. With the technological innovations,
the high pressure steam generated in boilers can in turn be used to rotate the
turbo generator blades to produce electric current. The process employed here to generate power is
called cogeneration which essentially implies the production of two forms of
energy, electricity and heat. The power thus generated can be used for meeting
the requirements of the sugar mill and the surplus can be fed into the grid.
Cogeneration
or production of electricity in combination with another industrial process is
not limited to sugar mills alone. There are several other industries such as
paper and pulp, textile, fertilizer, petroleum, petrochemicals and food
processing which require electrical as well as thermal energy for their
operations and therefore can use cogeneration as a process. The total fuel
consumption is significantly reduced when “co-generation” or “combined heat and
power” (CHP) is applied. The overall efficiency of energy use in cogeneration
mode can be up to 85 per cent and above in some cases.
In the present scenario, where price of
fossil fuels is shooting up and there is shortage and non-availability of coal,
cogeneration appears to be a promising development. The thrust on distributed
generation and increasing awareness for cutting green house gases emissions
increases the need of processes like cogeneration. Also it helps in controlling
pollution from fossil fuels.
The Ministry
of New and Renewable Energy is promoting cogeneration through various incentive
based schemes. Biomass Cogeneration programme in India is currently divided into two
components (i) Bagasse based (ii) Non-Bagasse based . While bagasse
cogeneration is essentially sugar mills oriented non-bagasse biomass
cogeneration can be used in biomass industry.
Bagasse Based
Cogeneration
As
already explained, the bagasse based cogeneration is mainly centred in sugar
mills. India
is the world’s second biggest producer of sugarcane. Indian sugarcane production
during 2010-11 is estimated at 340 million tonnes. India’s 527 working sugar
mills crush around 240 million tonnes of cane per year and generate 80 million
tonnes of wet bagasse (50% moisture), of which they consume around 70 million
tonnes for meeting captive requirements
of power and steam. Thus, electricity production through cogeneration in
sugar mills in India
is an important avenue for supplying low cost, non-conventional power.
Indian
efforts for promotion of bagasse cogeneration started with two pilot projects
taken up in cooperative sugar mills in Tamil Nadu in 1988-89 for generation of
surplus power and feeding it to the grid. Though possibilities of additional
power generation through cogeneration in sugar industry has been known for long,
but their usage started in a significant manner only after 1994, after
announcement of programme on bagasse based cogeneration by the Government.
A
capacity of around 1854 MW of surplus power generation has so far been
commissioned in 170 sugar mills in the states of Andhra Pradesh, Bihar,
Haryana, Karnataka, Maharashtra, Punjab, Tamil
Nadu, Uttar Pradesh and Uttarakhand. More than 200 MW of projects in about 20
private sector sugar mills are under construction. Optimum bagasse cogeneration
benefits not only the sugar mills but also the sugarcane farmers as the value
addition to their cane is enhanced and thus they can realise more money for it.
Power Cogeneration in
Industries (Non-Bagasse) Programme
The
industrial sector today consumes approximately 35% of total electricity
generated in the country. At the same time, high quality stable power is
required to attain the higher growth rate projected for this sector. Majority
of industries in India
require both electrical and thermal energy. Today, they either buy power from
the State Electricity Boards, or generate their own power largely through
diesel generators and meet their thermal energy requirements through captive
means mostly utilizing fossil fuels such as coal, oil or natural gas. As fossil
fuels are limited, and have adverse environmental impact, it would be
appropriate to use non-conventional energy sources including biomass resources
such as crop residues and agro-industrial wastes for generation of energy in
the industries mainly through biomass gasification technology for meeting their
total/partial requirements for both electrical and thermal energy.
Industrial
co-generation has in the past not received adequate attention, as cheap power
and fuel were abundantly available. However, with increasing tariffs, and
unreliable supply of grid power, there is considerable opportunity for the
industrial sector to tap the potential for producing electricity and thermal
energy in the co-generation mode. In particular, there is significant potential
in breweries, caustic soda plants, textile mills, distilleries, fertilizer
plants, paper and pulp industry, solvent extraction units, rice mills,
petrochemical plants, etc. Furthermore, co-generation projects based on
conventional fuels such as coal, oil, lignite, gas and un/semi-utilized
wastes/rejects like dolochar, coal rejects and refinery mud, etc. can also be
installed in industry for meeting their power and energy requirements.
To meet the requirement of captive
power and thermal energy, the installation of biomass cogeneration projects
(excluding bagasse co-generation ) is
being promoted in industry, with at least 50% of power for captive use,
and a provision for the surplus power to be exported to the grid.
This has increased the use of non-conventional energy sources and conserves the
use of fossil fuels such as coal, oil and natural gas. Use of maximum of 25%
conventional fuels has been allowed in such projects. The promotional schemes
also provide for Grants-in-Aid to State Nodal Agencies, NGOs and other
concerned institutions for organizing seminars, workshops, training/orientation
programmes, technology validation, strategic studies, industry-wise sectoral
studies and performance monitoring & evaluation, etc.
New Initiatives for Promotion
of Cogeneration in India
BOOT
(Build, Own, Operate, Transfer) Model Cogeneration Projects in Cooperative
Sugar Mills: Provision for Central Financial Assistance has been made
for bagasse cogeneration projects taken up through BOOT model in cooperative
sector sugar mills set up by Special Purpose Vehicle or an Independent Power
Producer. In this case, the investment in cogeneration power plant with
concurrent modernisation is done by BOOT developers. This model has advantage
in terms of non-requirement of equity and loans by cooperative sugar mills and
nil liability to repay and limited risks. The cogeneration plant and assets
after BOOT period are to be handed over to cooperative sugar mills. The
Ministry of New and Renewable Energy has supported the BOOT model projects in Maharashtra and Tamil Nadu. BOOT model projects in 12 Co-operative Public
sector sugars mills in Tamil Nadu of aggregate capacity 180 MW and BOOT model
cogeneration projects in two cooperative sugar mills of Maharashtra
of total capacity 80 MW are under implementation. The Ministry plans to extend
this effort in the Co-operative/Public sector sugar mills in the states of
Karnataka, Andhra Pradesh, Gujarat & Uttar Pradesh, during the next two to
three years.
Boiler
Modification in Cooperative Sugar Mills: A number of recently
installed cooperative sugar mills have already employed the configurations to
enable them to undertake cogeneration power projects with minimum investment
through modification of existing boiler and matching turbine. Ministry of New
and Renewable Energy has modified the scheme for providing Central Financial
Assistance for boiler upgradation of cogeneration project in such sugar mills.
The
incentive based schemes and the technical support to the industry by the Ministry
of New and Renewable Energy for installing cogeneration based projects is
expected to give a big push to the non-conventional energy programme during the
twelfth Plan Period. (PIB Feature).
*******
*Scientist ‘F’,
Ministry of New & Renewable Energy, New
Delhi.
**Assistant
Director, Press Information Bureau, New
Delhi.
SS-30/SF-30/01-02-2012
RTS/HSN