Solutions Manual
Introduction to Biomass Energy Conversions, 2E Sergio Capareda
Chapters 1-14
Chapter 1
Biomass as an Energy Source
1.9 Problems and Discussion Issues
1.9.1 Simple Definitions
P1.1 Define or explain the following terms and list their common English and metric units:
(a) Energy
(b) Power
(c) Heating value
Answers:
a. Energy – is the ability to do work and the common unit is Joule or Btu
b. Power – is the rate of doing work and the common unit is Watt (J/s) or Btu/hr
c. Heating value is the amount of energy contained in a biomass resource per unit of
weight. The common unit used is MJ/kg in metric units or Btu/lb in the English
system of units
1.9.2 Energy Units
P1.2 Convert the world's energy consumption of 418 EJ into units of BTU. Convert the BTU
units into Quads, since BTU is a relatively smaller unit.
Solution:
a. Convert 424 EJ into Btu
J
J
J J
, b. Btu units into Quads
1.9.3 Net Energy Trends in US
P1.3 Plot the net energy use in the US from 2010 to 2020 using data from Table 1.1
(consumption minus production). Describe the trends in net energy use in the US.
Solution:
a. Subtract consumption from production column from Table 1 and plot the net energy. The
net energy graph follows:
Net Energy Use (Consumption-Production)
25.0
20.0
Net Energy USe (Quads)
15.0
10.0
5.0
0.0
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
-5.0
Year
b. The net energy has decreased from 2010 to 2018 and became negative in 2019 and 2020.
For 2019 and 2020, simply based on production and consumption, the US is a net
exporter of energy instead of net importer.
,1.9.4 Contribution of Energy Sources in the US Economy
P1.4 Make a pie chart showing the percentage contribution of each energy source consumed in
the US in 2020. Discuss the sources that comprised majority of use. Please use Table 1.2 for this
problem. What was the percentage of use for renewables?
Solution:
a. The energy sources are added and percentage is calculated. The result is shown in the
graph below.
US Primary Energy Consumption in 2020
Renewables, 11.6,
12% Coal, 9.2, 10%
Nuclear, 8.2, 9%
Natural Gas, 31.5,
34%
Petroleum, 32.2,
35%
Coal Natural Gas Petroleum Nuclear Renewables
b. About 34% of consumption comes from natural gas, followed by petroleum (35%).
Reneewables comprised around 12%.
, 1.9.5 Moisture Removal in Biomass
P1.5 Algae biomass is harvested with around 87% moisture (wet basis). Determine the amount of
moisture to be removed per 1000 kg of algae if the ideal safe storage moisture content is 13%.
Solution:
a. The total amount of moisture in this algae biomass is 870 kg and the dry weight is 130
kg. These results can also be calculated from the equation provided in this chapter as
shown below:
b. However, not all of this moisture will be removed to keep the biomass at 13% moisture
content. The dry weight of the final product will be calculated using the above equation,
and with the moisture content of 13% to estimate the new total weight of the product at
13% MC as shown below:
c. The wet weight of the 13% MC product is 149.4 kg and of this, the amount of moisture
will be 19.4 kg. Thus, the amount of moisture to be removed will be (870 - 19.4) = 850.6
kg. This problem is a little bit tricky.
Introduction to Biomass Energy Conversions, 2E Sergio Capareda
Chapters 1-14
Chapter 1
Biomass as an Energy Source
1.9 Problems and Discussion Issues
1.9.1 Simple Definitions
P1.1 Define or explain the following terms and list their common English and metric units:
(a) Energy
(b) Power
(c) Heating value
Answers:
a. Energy – is the ability to do work and the common unit is Joule or Btu
b. Power – is the rate of doing work and the common unit is Watt (J/s) or Btu/hr
c. Heating value is the amount of energy contained in a biomass resource per unit of
weight. The common unit used is MJ/kg in metric units or Btu/lb in the English
system of units
1.9.2 Energy Units
P1.2 Convert the world's energy consumption of 418 EJ into units of BTU. Convert the BTU
units into Quads, since BTU is a relatively smaller unit.
Solution:
a. Convert 424 EJ into Btu
J
J
J J
, b. Btu units into Quads
1.9.3 Net Energy Trends in US
P1.3 Plot the net energy use in the US from 2010 to 2020 using data from Table 1.1
(consumption minus production). Describe the trends in net energy use in the US.
Solution:
a. Subtract consumption from production column from Table 1 and plot the net energy. The
net energy graph follows:
Net Energy Use (Consumption-Production)
25.0
20.0
Net Energy USe (Quads)
15.0
10.0
5.0
0.0
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
-5.0
Year
b. The net energy has decreased from 2010 to 2018 and became negative in 2019 and 2020.
For 2019 and 2020, simply based on production and consumption, the US is a net
exporter of energy instead of net importer.
,1.9.4 Contribution of Energy Sources in the US Economy
P1.4 Make a pie chart showing the percentage contribution of each energy source consumed in
the US in 2020. Discuss the sources that comprised majority of use. Please use Table 1.2 for this
problem. What was the percentage of use for renewables?
Solution:
a. The energy sources are added and percentage is calculated. The result is shown in the
graph below.
US Primary Energy Consumption in 2020
Renewables, 11.6,
12% Coal, 9.2, 10%
Nuclear, 8.2, 9%
Natural Gas, 31.5,
34%
Petroleum, 32.2,
35%
Coal Natural Gas Petroleum Nuclear Renewables
b. About 34% of consumption comes from natural gas, followed by petroleum (35%).
Reneewables comprised around 12%.
, 1.9.5 Moisture Removal in Biomass
P1.5 Algae biomass is harvested with around 87% moisture (wet basis). Determine the amount of
moisture to be removed per 1000 kg of algae if the ideal safe storage moisture content is 13%.
Solution:
a. The total amount of moisture in this algae biomass is 870 kg and the dry weight is 130
kg. These results can also be calculated from the equation provided in this chapter as
shown below:
b. However, not all of this moisture will be removed to keep the biomass at 13% moisture
content. The dry weight of the final product will be calculated using the above equation,
and with the moisture content of 13% to estimate the new total weight of the product at
13% MC as shown below:
c. The wet weight of the 13% MC product is 149.4 kg and of this, the amount of moisture
will be 19.4 kg. Thus, the amount of moisture to be removed will be (870 - 19.4) = 850.6
kg. This problem is a little bit tricky.
