A hypothetical estimation of emission reductions in a

biomass power plant project

Dr. Oscar Coto

II National CDM Workshop

Belize

August 2011

General description of the project

• Electricity generation using rice husk that otherwise would have been burned in open sky non controlled combustion.

• Construction and operation of a new 20 MW with an energy conversion efficiency of 30%.

• Plant is scheduled to enter into operation on January 1st 2012.

• Estimated electricity generation of 147,627 MWh/year equivalent to 531 TJ/year.

• Rice husk has a calorific value of 0.013 TJ/ton rice husk.

• Area of influence of the project produces around 0.9 million tons of rice husk per year and only 0.3 million tons are currently used for other uses in the area.

• Boilers are going to be using supplemental fuel oil at a rate of 6 m3 per start of the boilers during an estimated 5 times a year.

• It is estimated that 15 ton diesel operated trucks are going to movilize the rice husk on trips that will average 120 km round trip for each trip.

Basic data

• Emission factor of the electricity grid is 0,5 t CO2/MWh.

• Emission factor of the diesel trucks transporting the rice husk is 0,001097 t CO2/km.

• Density of fuel oil is 890 kg/m3.• Calorific value of the fuel oil is 0,0402 TJ/t.• The CO2 content of the fuel oil is 75,96 t CO2/ TJ• GWP of methane is 21 times that of CO2. • TJ represents 1012 J

Some basic questions to answer

• Quantity of energy to be supplied by the rice husk to the boilers in TJ/year?

• Amount of rice husk that will need to be supplied to the power plant in tons?

• Fraction of the available rice husk available in the area that will be used by the project?

• Make a diagram of the boundaries of the project?

• Which types of sources and types of greenhouse gases should be considered for the purpose of emission reduction estimates?

• Estimate emissions of the baseline?

• Estimate project emissions?• Estimate leakage emissions?• Estimate emissions reduction on a

per year basis?• If the crediting period is 10 years

under the CDM what is the expected total emissions reductions for the project?

1. Quantity of energy to be supplied by the rice husk to the boilers in

TJ/year?

• 531 TJ-year/0.3 = 1,770 TJ/year of energy in the rice husk to be supplied to the power plant.

2. Amount of rice husk that will need to be

supplied to the power plant in tons

• Amount of energy supplied by rice husk / calorific value of the rice husk

• 1,770 TJ/ year x 1/0.013 TJ/ton

• 136,153 tons of rice husk

3. Fraction of the available rice husk in the area that will be used by

the project?

• Available biomass in the area = 0.9 million ton (produced) – 0.3 million tons (currently being used by other users) = 0.6 millions tons rice husk available

• Fraction = 136,153 tons / 600,000

• Fraction = 22.69% meaning that …

4. Make a diagram of the boundaries of the project

5. Which types of sources and types of greenhouse

gases should be considered for the purpose of emission

reduction estimates?• Baseline: grid emissions• Project: combustion of diesel oil in the

transportation trucks, combustion of fuel oil during boiler start ups

• Leakage: please discuss?• Which are the types of GHG involved in

each of the sources?

6. Estimate emissions of the baseline?

• BLE= Electricity generated x grid emission factor

• BLE = 146,627 MWh/year x 0.5 ton CO2/MWh

• BLE = 73.313 ton CO2/year

7. Estimate project emissions?

• Transportation• PET = Amount of km travelled by trucks

x fuel emission factor of the combustion of diesel in those trucks

• Amount of km travelled = tons of biomass to be moved / truck capacity x average travel distance per round trip

• Amount of Km travelled = 136,153 / 15 x 120

• Amount of km travelled = 1,089,224 km

• PET = 1,089,224 km x 0,001097 t CO2/km

• PET = 1,194.8 ton CO2/year • Auxiliary fuel oil use• PEAF = Amount of fuel oil used

per year x emission factor of the combustion of fuel oil

• Amount of fuel oil used = 6 m3 x 5 = 30 m3 of fuel oil per year

• Amount of fuel oil = 30 m3 x 890 kg/m3 / 1000 = 26.7 tons of fuel oil/year

• Equivalent to 26.7 tons x 0.0402 TJ/ton = 1.07 TJ/year

• PEAF = 1.07 TJ /year x 75.96 ton CO2 /TJ• PEAF = 81.27 ton CO2/year

• Project Emissions (PE)• PE = PET + PEAF• PE = 1,194.8 ton CO2/year +

81.27 ton CO2/year

• PE = 1.276 ton CO2 / year

8. Estimate leakage emissions?

• LE = ?

•0

9. Estimate emissions reduction on a per year

basis?Emissions reductions (ER) =

Baseline emissions (BLE) –

Project emissions (PE) –

Leakage emissions (LE)

• ER = 73,313 tons CO2/year – 1.276 ton CO2/year – 0

• ER = 72,037 ton CO2/year

• Over 10 years would amount to 720,370 tons CO2