Exercise REN.1
A country produces the following types of wood for commercial purposes.
Type of wood / Quantity in m3 / Density (kg/m3) / kt (thousand tonnes)Mukarati / 300,000 / 865
Mushamba / 210,000 / 530
Mupfuti / 900,000 / 705
TOTAL / 1005 kt
1. Calculate the total production of wood in m3 and kt.
The total amount of wood produced = 300000*865/10^6+210000*530/10^6+900000*705/10^6 = 1005 kt
2. Calculate the weighted average density of the wood production in kg/m3.
The weighted average = (300000*865 + 210000*530 + 900000*705) / (300 000 + 900 000 +210 000) = 713 (Kg/m³)
3. Using the information below, determine the indigenous production that should be reported in the questionnaire
This locally produced wood is consumed in such way:
Ø 500 kt are used to make charcoal
Ø 55 kt are used as fuel by a company that produces paper
Ø 200 kt are used for heating and cooking in households
Ø 150 kt are used to build furniture <= Do not report in the Biomass Questionnaire
Ø The rest is used for heating purposes by a company producing glass
4. Open “Exercise_REN.1.xlsm” and enter the indigenous production and the consumption of wood in the Biomass questionnaire.
Indigenous production to be reported = 1005 – 150 = 855 kt
5. Calculate the charcoal production.
The energy efficiency of the Charcoal production plant is 40 % (provided by the plant). Use this figure to calculate the output (in kt) of charcoal.
Note the default calorific values of wood and charcoal are written in the questionnaire.
Wood used to make charcoal in energy units = 500*14000/1000 = 7000 TJ
Charcoal production = 7000*0.4 = 2800 TJ = (2800/30800)*1000 = 91 kt
6. Enter the charcoal data in the appropriate areas of the Biomass questionnaire.
Out of the charcoal production 50 kt are used to heat charcoal manufacture facilities and the rest is used for heating/cooking in restaurants
7. Report the following information on wood in the questionnaire.
According to a survey, 200 kt of firewood is self-collected by households and farmers. We assume that half of the amount is for domestic use and the other half is for heating the barns and storage buildings in farms.
Exercise REN.2
Open the file “Exercise_REN.2.xlsm”.
1. Enter the following data into the Biomass questionnaire:
A solid waste treatment site produces landfill gas naturally by the decomposition of organic material, such as food and yard waste (2 860 TJ net). The municipality consumes 1 180 TJ for heating purposes. Also, the waste disposal site uses the rest of the above gas to produce electricity to use for their waste treatment activity.
The same municipal waste treatment site also has an incinerator that burns waste directly (300 000 tonnes) to produce electricity. We can assume that half of the waste burnt has a non-renewable origin.
Beware: the Biomass questionnaire reports only waste from renewable origin.
This country also produces 13 543 kt of biogasoline. It also imports 2 922 kt, exports 11 525 kt and consumes 891 kt directly as fuel in agriculture. All the biogasoline left is blended with motor gasoline.
2. After having reported all the information, go to the Electricity Questionnaire. What do you notice?
In the Electricity questionnaire now we can see in Biomass a quantity in TJ of fuels used as input to produce electricity. This means that there will have to be a corresponding output reported in the electricity questionnaire too.
Exercise REN.3
1. Use the information given below to fill out the yellow cells in the OLADE wood estimation tool (“Wood estimation tool.xlsx”).
A recent population and household survey conducted in country A revealed the following information:
· The total population is 3 000 000 people out of which 2 000 000 people live in urban areas. The rest live in rural areas.
· The average number of persons per household in urban areas is 3.5 and for rural areas it goes up to 5 persons per household.
· In urban areas, 15% of households use only firewood as fuel, 7% use firewood as primary source of fuel and 20% use it as secondary fuel as complement to another primary fuel.
· In rural areas, 50% of households use only firewood as fuel, 14% use firewood as primary source of fuel and only 2% use it as secondary fuel as complement to another primary fuel.
2. What is the total wood consumption in country A? 1008.0 kt
Another survey in Country B reveals the following:
· The total population of 10 000 000 people out of which 4 000 000 people live in urban areas. The rest live in rural areas.
· The average number of persons per household in urban areas is 2 and for rural areas it goes up to 6 persons per household.
· In urban areas, 5% of households use only firewood as fuel, 10% use firewood as primary source of fuel and 40% use it as secondary fuel as complement to another primary fuel.
· In rural areas, 60% of households use only firewood as fuel, 25% use firewood as primary source of fuel and only 1% use it as secondary fuel as complement to another primary fuel.
3. What is the total wood consumption in country B? 4786.9 kt
4. Make a comparison of the results between both countries.
· Wood consumption in Country B is 4 times bigger than Country A and this might be because of the following reasons:
ü Note the difference in total population in the 2 countries. Country A = 3 millions and Country B = 10 millions.
ü In Country A the majority lives in urban areas whereas in Country B the majority lives in rural areas.
ü Since more people live in rural areas in Country B this results in wood used more often as single or primary source of fuel. In urban areas people tend to use more modern fuel like LPG for cooking.
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