National Exhibition and Seminar (Title : Climate Change Mitigation : Role of Renewables) on Renewable Energy . Dhaka, Bangladesh, 24-25 March, 2008
Focus on Climate Change Mitigation: Role of
Renewable
Electric Power Generation From Rice Husk
Khursheed-Ul-Alam, German Technical Cooperation (GTZ), Dhaka
Shahidul I. Khan, Deptt of Electrical & Electronic Engg, BUET
At a glance
• Electric power from Rice Husk and Technical and economic feasibility
• Type: Stand alone or grid connected power plants
• Range: 200-250 kW or 1-6 MW
The potential & Location of Power Generation Plants
• Annual paddy production: 40 – 45×105 MT
• Assuming 20% of weight is converted into husk, ~ 8 – 9 ×105 9 MT of husk annually.
• 2 kh husk equivalent to 1 kWh electricity production.
• Theoretically, 400 MW power plant with 4 × 105 9 MT husk.
• 100,000 rice mills in Bangladesh
• Dinajpur, Sherpur, Naogaon, Chapao Nawabganjk, Ishwerdi, Kaliakoir
• Maximum are small capacity mills, 5 -10 MT/day
• 490 Lower-mid sized mills, 25 – 50 MT/day
• 50 Large sized mills, 30 – 120 MT/day
• Realistic estimatiom: 100 MW from rice husk, generating unit sizes 250 – 300 MVA.
Rice
Husk - the appropriate Biomass
Fuel for Bangladesh
• WHY RICE HUSK ??
• Rice Husk is an unique Biomass Fuel of good calorific value
• (Heat Value : Abt.14 MJ (or 14,000 kJ) per kg & ‘Carbon-neutral’
• Bangladesh is a major ‘Rice Country’. It produces on the average about 40,000,000 MT of Paddy per Year, the Husk
production (@ 20% of Paddy), being about 8,000,000 MT/Year
• Bangladesh has over 100,000 Rice Mills all over the country which uses both thermal energy (of steam produced by burning rice husk for Parboiling of Rice) & Electric Power (from grid).
for entire operation of the mill (milling, boiler pumps, lighting etc.)
The Potential for Power Generation from Rice Husk [ Ptheor & Ptech.]
Ptheor (MW) = 417 MW, say about 400 MW
50% of 8,000,000 MT/Yr. Rice Husk x 1000 kg / MT
2 kg Husk / kWh x 16 hrs per operation day x 300 d/Yr. x 1000
Ptech. (MW) = 100 MW, considering a whole range
of practical parameters. [ About 500 Rice Mills x 200 kW
which are of mid to larger sizes and are or will be having sufficient husk surplus
for power generation due to efficient Boilers - existing and to be improved]
Husk Mass Balance Flow Chart to match thermal & Electrical Energy need of a 36,000 kg/day Paddy Processing Capacity
TECHNO-ECONMIC VIABILITY OF HUSK-BASED POWER PLANTS
• Assumptions : (i) 100% Producer Gas based Engine-Gensets
(ii) Husk consumption : 1.6 - 1.8 kg per kWhr.
(iii) Husk Price : Tk. 20/20 kg Bag (Tk.1.00/kg)
(iv) Fixed Bed Gasifier for 250 kVA, Fluidized Bed
for > 600 kVA (up to MW ranges)
Small / Medium-large Captives Central MW range Plants
Plant Size 200 kW 600 kW 2 MW 6 MW
Fin. Aspects
• INVESTMENT(US$) 250,000.- 500,000.- 1,400,000.- 3,900,000.-
• FIRR (%) 13.82 18.75% 24.61% 26.92%
STRATEGIC ACTION PLANS & GoB POLICY SUPPORTS
RECOMMENDED FOR IMPLEMENTATION
a detailed survey of size distribution & energy situation (both thermal & electrical) of rice mills located in cluster areas to be conducted immediately
2) one small (e.g. 250 kva) and one mid-large sized (e.g. 600 kw) rice mill should be supported by technical assistance & funds to test the 100% producer gas based technology & the profitability on a fast track basis (captive ‘flagships’)
3) based on results of detailed survey (as under sl. above megawatt range central plants in rice mill
cluster areas to be encouraged (north bengal)
4) special power purchase tariffs to be introduced
by berc to encourage husk based ret power.
