**4. Potential of biomass in Africa**

*Biotechnological Applications of Biomass*

**100**

**Figure 2.**

Africa

Africa

**Table 1.**

*Percentage of forest cover in Africa [28].*

Southern and Eastern

Central and Western

**Region Forested land** 

**area (1000 ha)**

*Forest and wooded areas in Africa according to the FAO 2005 statistics [27].*

crops for biofuel production. The feedstock for such processes comes from: (1) first generation food crops such as cereals, sugarcane and vegetable oils, (2) from second generation crops such as wood, wastes and bagasse and (3) from third generation organisms such as algae. It is not easy to quantify the use of energy crops due in Africa due to their affiliated competition with food demands especially in famine prone areas of sub-Saharan Africa. Additional challenges including food-fuel competition exacerbated by corruption, weak governance, political instability and competition for land slow down efforts aimed at modernizing biomass for energy in most African countries [30]. IEA [32] expressed optimism that with the appropriate policies, African countries including Uganda, South Africa, Nigeria, Ghana and Mozambique could use biofuels to meet energy demands of their respective transport sectors. It is from this optimism that several examples of biomass use in Africa have been documented. These include bioethanol generation from sugarcane

Northern Africa 131,048 8.6 94,609 10,207

Total Area 645, 412 21.4 406,100 21,339

**% Land area Other wooded** 

226,534 27.8 167,023 10,345

277, 829 44.1 144,468 788

**land (1000 ha)**

**Other land with tree cover (1000 ha)**

The potential of biomass in Africa has been examined in a number of studies especially in relation to available land [34, 35, 37]. These studies however focus on productive areas compared to arid and semi-arid regions. In Africa however, most of the area is largely arid of semi-arid characterized by mismanaged natural resources, low productivity and high vulnerability to climate change and soil erosion, which worsens the continent's poverty crises. The potential of biomass is therefore generalized using two aspects: (1) the availability of land and the viable production systems (technical potential) and (2) the expenditure and income resulting from biomass production (economic potential) that vary from humid to arid and semi-arid areas. Ultimately, with these considerations, the economic potential of bioenergy generation is affected. The next section focuses on Africa's biomass potential in relation to its technical and economic potential.

#### **4.1 Technical potential**

The technical potential of biomass is classified into two: (1) available land for bioenergy production and (2) viable biomass production systems. Available land defines the land left after current high biodiversity, agricultural and unsuitable areas are excluded. In this context, unsuitable areas include steep slopes, deserts and cities while high biodiversity areas include wetlands, forests, biodiversity hotspots and protected areas. In this context, Africa has a great technical potential of biomass as it has ample land for growth of bioenergy crops [27] and has serious electricity supply problems especially in rural areas steered up by poverty and

**Figure 3.** *The suitability of growing (a) sugarcane, (b) maize and (c) sorghum in Africa [40].*


#### **Table 2.**

*Some of the bioenergy crops grown in Africa, their climatic conditions, estimated yield rates and producing countries [38–39].*

**Figure 4.** *The suitability of growing (a) cassava, (b) palm oil and (c) jatropha in Africa [40].*

these factors could stimulate the use of biomass as an alternative energy source [30]. Kemausuor [38] supported the suggestion that Africa has high biomass potential by showing that its available land, harvested residues and bioenergy crops are higher compared to those of other parts of the world as shown in **Figure 3**. The figures on the available land by FAO also confirm the sufficiency of land for production of fuel wood and other bioenergy crops. However, the characteristics of African land such as its vulnerability to soil erosion, low productivity and misuse of natural resources coupled with traditional biomass uses are limiting factors to its optimal exploitation [24, 30]. Africa has many biofuel options from the many production systems of plants such as sugarcane, corn, sweet sorghum,

**103**

*The Potential of Biomass in Africa and the Debate on Its Carbon Neutrality*

**Africa**

0.07 0.07 0.05 0.08 0.08 0.07 0.08 0.05


36 35 69 57 37 26 40 39


7 10 15 9 6 7 7 6

20 20 93 22 22 20 22 93

0.3 0.3 4 0.4 0.4 0.3 0.4 1

2102 2226 1521 2332 2332 1998 2332 2102


12.4 9.5 8.7 7.4 8.1 12.4 10 5.5


2.7 2.5 2.3 2.7 2.6 2.4 3.1 2.5


4.9 8.9 4.8 2.8 3.4 7.5 3.8 2.3

**Senegal Mali Kenya Burkina** 

**Faso**

**Botswana**

cassava, palm oil and jatropha that are all energy crops [39]. The first three crops are collectively known as the ethanol crops while the last two are useful in biodiesel production. All the crops are economically and technically feasible in various parts of Africa based on their suitable conditions, yields from every hectare and some

*The labour, land, transport and fertilizer costs of energy crops in some African countries in comparison to their* 

Ethanol crops were initially developed for feed and crop production but their energy potential has suited the use of their biomass. Maize and sugarcane have greater potential since they are cultivated in many African countries at both smalland large-scale levels. Biodiesel crops include examples such as sunflower, castor oil, sesame, rapeseed, coconut, soya bean, jatropha and palm oil. However, for Africa palm oil and jatropha are focused on because of the high yield rates for every hectare and capacity to produce biofuel, respectively [39]. Areas where these energy

African producers summarized in **Table 2** [39].

*DOI: http://dx.doi.org/10.5772/intechopen.93615*

**Country Zambia Tanzania South** 

Transportation costs (US\$t−1km−1)

Transport distance for cassava Arid areas (km)

Semi-arid areas (km)

Semi-arid areas (km)

Land costs (US\$ ha−1y−1)

Labour costs (US\$ h−1)

Yield rate of fuelwood Arid areas (t ha−1 y−1)

Semi-arid areas (t ha−1 y−1)

Semi-arid areas (t ha−1 y−1)

Semi-arid areas (t ha−1 y−1)

**Table 3.**

*yield rates [27].*

Yield rate of cassava Arid areas (t ha−1 y−1)

Yield rate of jatropha Arid areas (t ha−1 y−1)

Fertilizer costs for NPK (US\$)

(km)

Transport distance for fuelwood and jatropha Arid areas


#### *The Potential of Biomass in Africa and the Debate on Its Carbon Neutrality DOI: http://dx.doi.org/10.5772/intechopen.93615*

#### **Table 3.**

*Biotechnological Applications of Biomass*

**production**

Corn Can grow everywhere with enough watering

and tropical areas

Cassava Above 1000 m attitude in tropical climate

Palm oil Above 700 m attitude in humid tropic climate

Jatropha Above 500 m attitude and as low

and tropical climate

**Suitable conditions for optimal** 

Sugarcane 1600 meters (m) above sea level 4000 liters/

2500 m attitude in dry temperate

as 300 mm rainfall in semi-arid

**Yield for every hectare**

hectare (l/ha) in Africa

1750 l/ha in Africa

3000 l/ha in Africa

*Some of the bioenergy crops grown in Africa, their climatic conditions, estimated yield rates and producing* 

**Producing countries**

Mauritius, Zimbabwe, Swaziland, Kenya, Sudan,

Nigeria, South Africa

Angola, Ghana, Mozambique,

Ethiopia, Nigeria

DR Congo, Nigeria

Ghna, DR Congo, Cote d'Ivoire, Nigeria

South Africa

700 l/ha in Africa Tanzania, Kenya, Ethiopia,

3000–6000 l/ha Burkina Faso, Sudan,

40–2200 l/ha oil Tanzania, Mozambique, Mali, Ghana

**Bioenergy crop**

Sweet sorghum

**Table 2.**

*countries [38–39].*

**102**

**Figure 4.**

these factors could stimulate the use of biomass as an alternative energy source [30]. Kemausuor [38] supported the suggestion that Africa has high biomass potential by showing that its available land, harvested residues and bioenergy crops are higher compared to those of other parts of the world as shown in **Figure 3**. The figures on the available land by FAO also confirm the sufficiency of land for production of fuel wood and other bioenergy crops. However, the characteristics of African land such as its vulnerability to soil erosion, low productivity and misuse of natural resources coupled with traditional biomass uses are limiting factors to its optimal exploitation [24, 30]. Africa has many biofuel options from the many production systems of plants such as sugarcane, corn, sweet sorghum,

*The suitability of growing (a) cassava, (b) palm oil and (c) jatropha in Africa [40].*

*The labour, land, transport and fertilizer costs of energy crops in some African countries in comparison to their yield rates [27].*

cassava, palm oil and jatropha that are all energy crops [39]. The first three crops are collectively known as the ethanol crops while the last two are useful in biodiesel production. All the crops are economically and technically feasible in various parts of Africa based on their suitable conditions, yields from every hectare and some African producers summarized in **Table 2** [39].

Ethanol crops were initially developed for feed and crop production but their energy potential has suited the use of their biomass. Maize and sugarcane have greater potential since they are cultivated in many African countries at both smalland large-scale levels. Biodiesel crops include examples such as sunflower, castor oil, sesame, rapeseed, coconut, soya bean, jatropha and palm oil. However, for Africa palm oil and jatropha are focused on because of the high yield rates for every hectare and capacity to produce biofuel, respectively [39]. Areas where these energy crops are grown in Africa based on their suitability and according to the IIASA / FAI [40], statistics are shown in **Figures 3** and **4**.

#### **4.2 Economic potential**

Economic potential of biomass focuses on its production for profitable gains and with economic viability. To assess this biomass potential in Africa, costs of energy crop production such as inputs, labor, land and transportation costs from the farm until the last stage of energy conversions are considered. Other considerations according to Dasappa [27] include taxes, retail and wholesale margins, fertilizer and distribution costs. They help in comparing the economic viability of biomass energy with conventional energy prices. Some of these costs in eight named countries of Africa in comparison to the average yields of fuel wood, a biodiesel (jatropha) and ethanol (cassava) crop and according to literature are summarized in **Table 3** [27].

From the estimates of literature, the costs vary based on countries and there is need to adopt modern biomass uses that focus on efficiency and effectiveness even at the production levels [33, 34]. The costs in arid areas are higher compared to the semi-arid areas due to the challenges of land aforementioned in this chapter. The estimates are however, a simplification of the actual situation and more accurate and region specific estimates are needed as Dasappa [27] highlighted.

#### **5. The carbon neutrality debate of biomass**

Bioenergy or biomass energy has received a lot of attention globally as a viable alternative to conventional energy sources from fossil fuels because of its capacity to enhance energy security, result to economic growth and at the same time, cause minimal environmental impacts [41]. With this high attention drawn to biomass production and its subsequent conversion to bio power, researchers, government agencies, biomass feedstock generators and environmentalists are equally paying attention to its carbon neutrality issue. The carbon neutrality debate revolves around the ability of biomass production and conversion to energy processes resulting to zero increase in the greenhouse gas (GHG) levels in the atmosphere following a full life cycle basis. The debate influences future adoption to biomass sources and legislation on their use. During the contest, some bioenergy generators and biomass feedstock farmers support that associated energy resources are neutral since carbon released during biomass generation originates from feedstock that withdrew carbon from the atmosphere during growth. On the other hand, some environmentalists argue that bioenergy is not carbon neutral since the GHG emissions released in production of a unit of energy in a case such as combustion could even be higher than those of fossil fuels depending on the biomass type. Van Renssen [42] bases the debate on carbon neutrality of biomass energy sources to the inaccurate GHG emission assessment, which could result to long-term environmental issues.

To understand the debate around the carbon neutrality of biomass, this chapter does a summative focus on the carbon cycle. The cycle involves many pathways where carbon is exchanged between land, water and the atmosphere. Anthropogenic activities emit CO2 and contribute to the carbon cycle. The contribution of CO2 by humans is considerably small compared to other sources but once released to the environment; CO2 is taken up by oceans, soils and vegetation at a slower rate compared to the emission rate [43]. Unless there are available CO2 sinks in ocean and on land, the gas is likely to accumulate in the atmosphere causing modifications on the climatic conditions of the earth. Energy production is one of

**105**

*The Potential of Biomass in Africa and the Debate on Its Carbon Neutrality*

energy production activity occurs in three ways: [43].

ronment compared to the emission rates.

lower net increments of GHG emissions.

transportation processes should sum up to zero.

the human activities that releases significant amounts of CO2. The net result of any

1.Carbon positivity, which defines activities that release CO2 to the environment.

2.Carbon negativity, which defined activities that draw CO2 more from the envi-

3.Carbon neutrality that defines activities leading to CO2 absorption and release

To be carbon neutral, biomass has to meet the following four conditions

1.Compared to conventional energy sources, biomass sources should result to

2.Emissions of biomass overall life cycle from the cultivation, harvesting and

3.If biomass cultivation draws more atmospheric CO2 compared to resultant

4.If by nature, biomass sources are carbon neutral then their products will be

A number of policies consider the burning of biomass as carbon neutral irrespective of their sources. Concurrently, the policies acknowledge the presence of carbon emissions using fossil fuels to process biomass but fail to narrow it down to CO2 [45]. Through this error when computing emissions from bioenergy, they conclude that all biomass-based energy sources are carbon neutral. According to Haberl et al. [41] such policies are inaccurate. In another assumption, carbon neutrality is assumed since combustion of biomass releases the carbon that was initially drawn from the atmosphere as the plants were growing. This is a baseline error since the ideology fails to acknowledge that if energy crops were not harvested, they would

The suppositions by Miner [44] are contentious and escalate the carbon neutrality debate. For example, the assumption that biomass is carbon neutral naturally, fails to account for GHG emissions that occur during energy crop tendering processes such as fertilization. Additionally, the demand to remove CO2 resulting from biomass growth equally means more planting of such crops. To assess the carbon neutrality of biomass compared to conventional fossil fuels, it is important to focus on their specific carbon cycles and identify differences as shown in **Figure 5**. Bioenergy has renewable sources of carbon in that plants can be re-grown and result to stable carbon concentrations compared to fossil fuel energy with finite sources of carbon that lead to additional CO2 concentrations. Emissions from biofuels mainly occur from bio power technology type, feedstock production and transformation. This fact therefore suggests that the use of biomass as an alternative to conventional energy sources eliminates or reduces emissions from fossil fuels but also results to its own emissions and cannot possibly be carbon neutral as Bird et al. [45] suggested. The authors cited the example of combusting a metric ton of bone-dry wood that emits 1.8 tons of atmospheric CO2. These differences coupled with the fact that feedstock growth consumes CO2 could justify the ideologies of biomass as carbon

*DOI: http://dx.doi.org/10.5772/intechopen.93615*

of equal measure.

according to Miner [44].

emissions.

neutral too.

neutral according to Bracmort [43].

*Biotechnological Applications of Biomass*

**4.2 Economic potential**

[40], statistics are shown in **Figures 3** and **4**.

crops are grown in Africa based on their suitability and according to the IIASA / FAI

Economic potential of biomass focuses on its production for profitable gains and with economic viability. To assess this biomass potential in Africa, costs of energy crop production such as inputs, labor, land and transportation costs from the farm until the last stage of energy conversions are considered. Other considerations according to Dasappa [27] include taxes, retail and wholesale margins, fertilizer and distribution costs. They help in comparing the economic viability of biomass energy with conventional energy prices. Some of these costs in eight named countries of Africa in comparison to the average yields of fuel wood, a biodiesel (jatropha) and ethanol (cassava) crop and according to literature are summarized in **Table 3** [27]. From the estimates of literature, the costs vary based on countries and there is need to adopt modern biomass uses that focus on efficiency and effectiveness even at the production levels [33, 34]. The costs in arid areas are higher compared to the semi-arid areas due to the challenges of land aforementioned in this chapter. The estimates are however, a simplification of the actual situation and more accurate

and region specific estimates are needed as Dasappa [27] highlighted.

Bioenergy or biomass energy has received a lot of attention globally as a viable alternative to conventional energy sources from fossil fuels because of its capacity to enhance energy security, result to economic growth and at the same time, cause minimal environmental impacts [41]. With this high attention drawn to biomass production and its subsequent conversion to bio power, researchers, government agencies, biomass feedstock generators and environmentalists are equally paying attention to its carbon neutrality issue. The carbon neutrality debate revolves around the ability of biomass production and conversion to energy processes resulting to zero increase in the greenhouse gas (GHG) levels in the atmosphere following a full life cycle basis. The debate influences future adoption to biomass sources and legislation on their use. During the contest, some bioenergy generators and biomass feedstock farmers support that associated energy resources are neutral since carbon released during biomass generation originates from feedstock that withdrew carbon from the atmosphere during growth. On the other hand, some environmentalists argue that bioenergy is not carbon neutral since the GHG emissions released in production of a unit of energy in a case such as combustion could even be higher than those of fossil fuels depending on the biomass type. Van Renssen [42] bases the debate on carbon neutrality of biomass energy sources to the inaccurate GHG emission assessment, which could result to long-term environ-

To understand the debate around the carbon neutrality of biomass, this chapter does a summative focus on the carbon cycle. The cycle involves many pathways where carbon is exchanged between land, water and the atmosphere. Anthropogenic activities emit CO2 and contribute to the carbon cycle. The contribution of CO2 by humans is considerably small compared to other sources but once released to the environment; CO2 is taken up by oceans, soils and vegetation at a slower rate compared to the emission rate [43]. Unless there are available CO2 sinks in ocean and on land, the gas is likely to accumulate in the atmosphere causing modifications on the climatic conditions of the earth. Energy production is one of

**5. The carbon neutrality debate of biomass**

**104**

mental issues.

the human activities that releases significant amounts of CO2. The net result of any energy production activity occurs in three ways: [43].


To be carbon neutral, biomass has to meet the following four conditions according to Miner [44].


The suppositions by Miner [44] are contentious and escalate the carbon neutrality debate. For example, the assumption that biomass is carbon neutral naturally, fails to account for GHG emissions that occur during energy crop tendering processes such as fertilization. Additionally, the demand to remove CO2 resulting from biomass growth equally means more planting of such crops. To assess the carbon neutrality of biomass compared to conventional fossil fuels, it is important to focus on their specific carbon cycles and identify differences as shown in **Figure 5**. Bioenergy has renewable sources of carbon in that plants can be re-grown and result to stable carbon concentrations compared to fossil fuel energy with finite sources of carbon that lead to additional CO2 concentrations. Emissions from biofuels mainly occur from bio power technology type, feedstock production and transformation. This fact therefore suggests that the use of biomass as an alternative to conventional energy sources eliminates or reduces emissions from fossil fuels but also results to its own emissions and cannot possibly be carbon neutral as Bird et al. [45] suggested. The authors cited the example of combusting a metric ton of bone-dry wood that emits 1.8 tons of atmospheric CO2. These differences coupled with the fact that feedstock growth consumes CO2 could justify the ideologies of biomass as carbon neutral according to Bracmort [43].

A number of policies consider the burning of biomass as carbon neutral irrespective of their sources. Concurrently, the policies acknowledge the presence of carbon emissions using fossil fuels to process biomass but fail to narrow it down to CO2 [45]. Through this error when computing emissions from bioenergy, they conclude that all biomass-based energy sources are carbon neutral. According to Haberl et al. [41] such policies are inaccurate. In another assumption, carbon neutrality is assumed since combustion of biomass releases the carbon that was initially drawn from the atmosphere as the plants were growing. This is a baseline error since the ideology fails to acknowledge that if energy crops were not harvested, they would

**Figure 5.**

*Carbon cycles of bioenergy compared to fossil fuel sourced energy [43].*

continue to absorb atmospheric CO2. The resultant carbon reductions are included in the global estimates of CO2 emissions in future and this in not precise since it results to double counting. Ritcher et al. [46] emphasized the computational error of carbon neutrality using the example of a hectare of cropped land that is left to reforest. In this case, the growing plants absorb atmospheric CO2 to form biomass. Some of the biomass is eaten by microorganisms, fungi and animals and released to the atmosphere while the other is stored in soils and vegetation during growth processes. The overall effect would be reduced CO2 emissions and a negative effect on global warming. On the other hand, if energy crops were cultivated to be combusted in power plants, fossil fuel based emissions would reduce but carbon emissions from the plants' chimneys would arise. Bird et al. [45] supported this line of thought claiming that for every unit of energy, CO2 emitted from the power plants would even be higher that fossil fuels because (1) the efficiency of combusting biomass compared to fossil fuel is lower and (2) biomass has lower unit energy potential compared to natural gas or petroleum based power. Therefore growing energy crops draws CO2 from the atmosphere but it foregoes the sequestration of this gas that would occur if the land was forested. The foregone CO2 atmospheric

**107**

*The Potential of Biomass in Africa and the Debate on Its Carbon Neutrality*

carbon emissions indirectly under the following circumstances:

withdrawals are not accounted in existent biomass GHG emission computation methods. The growth of forests in Ukrainian forests for instance after abandoning farmland resulted more carbon sinking at the rate of one ton per hectare of forested land annually [47]. The growth of energy crops causes more carbon to be sequestered in underground fossil fuels though the advantage has an opportunity cost of less carbon being stored in soils and plants. Biomass energy sources would reduce carbon emissions to be considered neutral if the former effect outweighs the latter. The use of food crops such as maize, cassava, sorghum for energy crops is a perfect scenario to demystify the carbon neutrality debate. The process does not compensate the emissions from its use and does not directly lead to additional growth of plants [48, 49]. However, the energy crops can significantly reduce

1.The crops sequester carbon from the atmosphere for longer periods since humans and animals consume them and then return carbon during respiration. If the crops are not replaced, they result to net carbon reductions and their consumption emits less CO2. However, the approach is not sustainable in

2.If more crops are concentrated per unit land, more carbon is absorbed. In the event more land is cultivated, carbon withdraws from the atmosphere are

In these two scenarios, carbon fluctuations due to land-use changes must be determined accurately. From the many considerations on biomass carbon neutrality made in this chapter, the main issue in the debate is the failure to consider the emissions that would result if bioenergy was produced from other alternatives apart from energy crops. This error results to incorrect GHG accounting [41]. Therefore, accurate GHG accounting should reflect the carbon stock losses during production of biomass, the energy consumed and consider the carbon withdrawals that would result if bioenergy was not used at all. In forested areas of countries at the northern hemisphere, biomass accumulation occurs [46, 50] resulting to more carbon sequestration. In events that the harvest of biomass does not surpass forest growth, carbon stocks are estimated to be constant and consequent GHG emission reductions can be realized [43, 51]. If forests are left to regrow following harvest, they realize the same carbon sequestration levels as the unharvested ones when carbon stock build up slows and stops at maturity. At that point, biomass use is considered carbon neutral. Such a realization could take many years and as such, atmospheric CO2 is retained longer in the atmosphere before removal by plants, which is the cause of climate change [48, 49]. Increasing the harvest times for forests in the long term for sustainable fuel wood supply decreases the carbon stocks resulting to a carbon debt that is repaid after longer periods even if forest conservation occurs [51]. Holistic GHG emission accounting from biomass sources of energy should consider plant growth rate in the presence and absence of bioenergy generation and the changes in

carbon storage in soils and plants as a result of the initiatives or otherwise.

Biomass is a useful energy source in most African countries and is used for thermal applications in addition to cooking and producing electricity. As an alternative source of energy, it is essential as large part of the continent do not have direct access to electricity and other conventional energy sources. Additionally the use

**6. Conclusions and recommendations**

*DOI: http://dx.doi.org/10.5772/intechopen.93615*

reducing GHGs.

likely to increase.

#### *The Potential of Biomass in Africa and the Debate on Its Carbon Neutrality DOI: http://dx.doi.org/10.5772/intechopen.93615*

*Biotechnological Applications of Biomass*

continue to absorb atmospheric CO2. The resultant carbon reductions are included in the global estimates of CO2 emissions in future and this in not precise since it results to double counting. Ritcher et al. [46] emphasized the computational error of carbon neutrality using the example of a hectare of cropped land that is left to reforest. In this case, the growing plants absorb atmospheric CO2 to form biomass. Some of the biomass is eaten by microorganisms, fungi and animals and released to the atmosphere while the other is stored in soils and vegetation during growth processes. The overall effect would be reduced CO2 emissions and a negative effect on global warming. On the other hand, if energy crops were cultivated to be combusted in power plants, fossil fuel based emissions would reduce but carbon emissions from the plants' chimneys would arise. Bird et al. [45] supported this line of thought claiming that for every unit of energy, CO2 emitted from the power plants would even be higher that fossil fuels because (1) the efficiency of combusting biomass compared to fossil fuel is lower and (2) biomass has lower unit energy potential compared to natural gas or petroleum based power. Therefore growing energy crops draws CO2 from the atmosphere but it foregoes the sequestration of this gas that would occur if the land was forested. The foregone CO2 atmospheric

*Carbon cycles of bioenergy compared to fossil fuel sourced energy [43].*

**106**

**Figure 5.**

withdrawals are not accounted in existent biomass GHG emission computation methods. The growth of forests in Ukrainian forests for instance after abandoning farmland resulted more carbon sinking at the rate of one ton per hectare of forested land annually [47]. The growth of energy crops causes more carbon to be sequestered in underground fossil fuels though the advantage has an opportunity cost of less carbon being stored in soils and plants. Biomass energy sources would reduce carbon emissions to be considered neutral if the former effect outweighs the latter.

The use of food crops such as maize, cassava, sorghum for energy crops is a perfect scenario to demystify the carbon neutrality debate. The process does not compensate the emissions from its use and does not directly lead to additional growth of plants [48, 49]. However, the energy crops can significantly reduce carbon emissions indirectly under the following circumstances:


In these two scenarios, carbon fluctuations due to land-use changes must be determined accurately. From the many considerations on biomass carbon neutrality made in this chapter, the main issue in the debate is the failure to consider the emissions that would result if bioenergy was produced from other alternatives apart from energy crops. This error results to incorrect GHG accounting [41]. Therefore, accurate GHG accounting should reflect the carbon stock losses during production of biomass, the energy consumed and consider the carbon withdrawals that would result if bioenergy was not used at all. In forested areas of countries at the northern hemisphere, biomass accumulation occurs [46, 50] resulting to more carbon sequestration. In events that the harvest of biomass does not surpass forest growth, carbon stocks are estimated to be constant and consequent GHG emission reductions can be realized [43, 51]. If forests are left to regrow following harvest, they realize the same carbon sequestration levels as the unharvested ones when carbon stock build up slows and stops at maturity. At that point, biomass use is considered carbon neutral. Such a realization could take many years and as such, atmospheric CO2 is retained longer in the atmosphere before removal by plants, which is the cause of climate change [48, 49]. Increasing the harvest times for forests in the long term for sustainable fuel wood supply decreases the carbon stocks resulting to a carbon debt that is repaid after longer periods even if forest conservation occurs [51]. Holistic GHG emission accounting from biomass sources of energy should consider plant growth rate in the presence and absence of bioenergy generation and the changes in carbon storage in soils and plants as a result of the initiatives or otherwise.
