We have been working on open-top down draft, re-burn gasification of bioresidues for the past three years and have successfully implemented 7 projects ranging in size from 20 kWe to 2 MWe, in India and abroad, using a wide range of biomass feedstock such as Casuarina, Eucalyptus, coconut shell. The gasifiers can use practically any woody biomass fuel containing upto 15% moisture and are used by our clients for both thermal applications and for power generation.
The typical thermal applications are for high grade heat (upto 1100 Degree C) such as for heat treatment furnaces, thermic fluid heaters, hot air generators, where, depending on budget constraints, producer gas has either partially or totally replaced fossil fuels. The typical power applications are as captive island units and for grid connection. Power can be generated both in the dual fuel mode and in the 100% gas mode. With conventional Diesel/HFO generators without any modifications, we have achieved liquid fuel replacement of upto 90% in the dual fuel mode. Power can also be generated with Diesel/HFO generators retrofitted with spark ignition systems enabling power generation on 100% producer gas. The cost of unit generation ranges from 3.65 cents in the 100% gas mode to 5.70 cents in dual mode using commercially available biomass (without considering any govt. handouts and subsidies, which always distort the cost structure). With some specific fuels like coconut shell, rice husk and cashew nut shell, we have also obtained by-products such as Activated Carbon, Precipitated Silica and CNSL resp.,thus reducing the effective cost of generation to 1.55 cents on 100% gas mode and 3.60 cents in the dual mode. Our systems are work horses with PLC controls and are built to last . Some of them have clocked more than 7500 hours in the industrial mode.
The technology is already proven and more than 24 installations in India and abroad are living proof of this. The technology package is provided by Professor Mukunda's team at Indian Institute of Science, Bangalore, India, and we undertake turn-key project implementation involving detail engineering of civil,mechanical, electrical, instrumentation and data acquisition through site identification, obtaining letting and permissions, system manufacture, installation and commissioning to on-site training of operating plant personnel and system performance monitoring. We also undertake O & M contracts and annual AMCs and are in the process of finalising some more projects on BOO & BOOT basis in India. We have recently moved our office to the following address :
Generalisations about gasification economics which may not be valid for all countries. While it is true that the cost of biomass harvesting (a labour intensive activity) in developed economies may be quite high and the soil productivity lower thus rendering the cost advantage unattractive, the situation in India (and other tropical countries) is entirely different.
For instance, we have installed several gasification systems for both thermal and electrical applications (replacing fossil fuels such as Light Diesel Oil, High Speed Diesel & Heavy Furnace Oil) at various geographical locations in India, and in most cases the total capital investment has been recovered from 12-18 months. The brief economics are as follows. I have given the figures in US currency (and in Indian Rs. in brackets) considering exchange rate of Rs. 48/00 per US $.
1) Landed cost of biomass/kg = 2.08 US cents (Re. 1.00)
2) Calorific equivalence of High Speed oil Diesel (or other oil) to biomass = 1:3.5 (Considering cold gas efficiency 85%)
3) Equivalent cost of biomass for 1 Lt. of = 2.08 x 3.5 = 7.29 cents (Rs. 3.50)
4) Cost of O & M on the gasification system/ lt of oil equivalent = 3.65 cents ( Rs. 1.75)
5) Interest and amortisation costs/lt. of oil equivalent = 4.06 cents(Rs. 1.95)(@ 17.5% p.a. on straight-line basis)
6) Total cost of biomass energy/ lt of oil equivalent = 15 cents (Rs. 7.20)
7) Landed cost of oil/lt. = 40.21 US Cents (Rs. 19.30)
8) Savings in diesel in switching to biomass gasification/lt of oil equivalent = 25.21 cents (Rs. 12.10)
You will therefore find that biomass is extremely attractive on economic considerations alone in this neck of the woods. The numbers are valid for both thermal and electrical applications and, from 01-04-02, the delivered cost of fossil fuels is benchmarked to world prices (barring cross subsidies to the transport and domestic sectors). Since the cost of diesel is currently partly cross-subsidised by gasoline, the real savings would certainly be brighter in a more equitable world.
Regards.
T R Krisnaswamy,
Energreen Power Ltd.,
First Floor, 'Ashroff',
# 1, Second Street,
Nandanam Extension,
Chennai, TN, India - 600 035.
Tel : 91(44) 4321339, 4322499
e-mail : energreenpower@lycos.com
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