Where is biomass found

Herbaceous energy crops are perennial plants that live for more than 2 years grasses that are harvested annually after taking 2 to 3 years to reach full productivity. These include switchgrass, miscanthus, bamboo, sweet sorghum, tall fescue, kochia, wheatgrass, and others. Short-rotation woody crops are fast-growing hardwood trees that are harvested within 5 to 8 years of planting.

These include hybrid poplar, hybrid willow, silver maple, eastern cottonwood, green ash, black walnut, sweetgum, and sycamore. Many of these species can help improve water and soil quality, improve wildlife habitat relative to annual crops, diversify sources of income, and improve overall farm productivity.

Agricultural Crop Residue There are many opportunities to leverage agricultural resources on existing lands without interfering with the production of food, feed, fiber, or forest products. Agricultural crop residues, which include the stalks and leaves, are abundant, diverse, and widely distributed across the United States.

Toggle navigation. Biomass energy technologies use renewable organic resources, also known as biomass, to produce energy-related products. Electricity; liquid, solid and gaseous fuels; heat; chemicals; and other energy-related products can all be derived from biomass resources.

Biomass power is the largest source of renewable energy worldwide. Biomass comes from both human and natural activities. However, it is worth noting that direct use of biomass is not always feasible and in some cases require additional treatment biologically or physically to prevent the effects of conventional fuels [ 1 ]. This book chapter focuses on the various sources of biomass in Africa and assesses their potential in addition to having a candid discussion on the carbon neutrality of biomass.

Three categories of biomass including forestry biomass, energy crops and wastes or residues will be discussed. The prospects of the chapter will help in drawing a roadmap to providing reliable energy for socio-economic growth in Africa while at the same time, taking precautionary measures to conserve the environment.

Biomass, which is sourced from organic matter from the biosphere animal or plant origin and through transformation of wastes, is a promising source of energy. This renewable energy source can be classified into three: 1 forestry biomass, 2 energy crops and 3 biomass from wastes and residues.

These three forms of biomass will be discussed in the following sections. Forests as terrestrial ecosystems store and generate biomass, which justifies their applicability as energy sources since time immemorial [ 8 , 9 ]. This biomass form differs based on topography, stand structure, site and management systems. Irrespective of the variations, forest is a primordial energy source due to its uniformity and availability globally as well its carbon neutrality [ 10 , 11 ].

Forest biomass is removed as harvests or in silvicultural activities. Forest biomass is classified into two categories: 1 energy plantations and 2 timber systems where energy is produced as forest residues.

Energy plantations are distinguished from agricultural crops from the ability to enhance their biodiversity, their variability globally, harvest flexibility, economic variability, low risk and their capacity to perform phytoremediation [ 12 , 13 ].

A number of factors such as the management practices, harvest cycle, rotation, density and the selection of species are considered in the growth of energy crops [ 14 ]. Forest residues include stumps, stems, limbs and tops of trees and their production depends on tree species, stem quality and stand structure [ 8 ].

The current share of forest biomass use is limited despite the known advantages of its use in energy production including the ability to convert it to transportation fuels, heat and electricity. The use of bioenergy and renewable wastes for energy supply accounted for 9.

Among these biomass supplies, Wood, wood fuel and wood residues produce heat and electricity and can be used indirectly by power plants combined with heat and power or directly by end users. Examples of forest biomass sources include wood pellets, pine wood chips, pine bark, beech woos, willow wood, poplar and eucalyptus wood [ 17 ].

This rate is by far higher compared to higher income developing countries of India and China. Although projections by the IEA as noted by Stecker et al. Energy crops are wild and cultivated crops, which produce biomass for various purposes. They exist as woody, herbaceous, perennial, or annual and generate raw materials for gaseous or liquid biofuels in addition to solid biomass. A number of factors including maintenance of land productivity, improved soil fertility, use of crop rotation systems, climate change adaptation and crop characteristics influence the successful production of energy crops [ 19 ].

Energy crops are used for three main purposes: 1 biodiesel, 2 bioethanol and 3 electric and thermal production [ 20 ]. Some of the crops used to produce biodiesel include Cynara cardunculus, cotton, Glycine max, Helianthus annuus and Brassica napus.

Energy crops used in bioethanol production include Beta vulgaris , Zea mays and Sorghum bicolor , wheat among other cereals. Miscanthus giganteus , Eucalyptus globulus and Arundo donax are used in electric and thermal production. According to Lynd et al. A number of conversion technologies transform the crops to energy. These technologies include biological processes such as fermentation, lignocellulose hydrolysis and anaerobic digestion as well as non-biological processes such as transesterification, pyrolysis, gasification and combustion.

African countries such as Kenya, Zimbabwe, South Africa, Tanzania, Ghana and Ethiopia have embraced the use of these biomass crops as energy sources in addition to the use of forest biomass, residues and other forms of wastes [ 21 ]. Municipal solid waste commonly known as garbage comprises of leather and wood by-products, leaves, clippings from grass, food wastes, cardboard, paper and biogenic material from plants and animals. All these form biomass and can be transformed to energy for heating or steam for electricity generation.

This has been done in developed countries such as the USA where in , 14 billion kilowatt-hours of electricity from combusting The remaining combustible weight was from non-biomass materials such as plastics. Landfill gas also made from biomass material is transformed to methane gas and used in energy production.

In Africa, the use of municipal solid waste for energy production has high potential as Scarlat et al. Bioenergy from biomass is the primary source of energy for more than 2. A similar trend is evident in the sub-Saharan Africa as shown in Figure 1b. Figure 1c Total biomass energy supply for the entire continent is at 28, petajoules PJ while in sub-Saharan Africa it is 21, and 15, PJ including and excluding South Africa, respectively, according to the IEA data of [ 18 , 26 ].

Apart from contributing to the primary energy demand in Africa, biomass also contributes significantly to the total final consumption. In poorer countries of Africa especially those of sub-Saharan Africa excluding South Africa, the tendency to use biomass for energy is even higher according to Dasappa [ 27 ]. Usually the uses are traditional referring to the inappropriate use of animal dung, agricultural residues, animal dung, tree residues and fuel wood for space heating, lighting and cooking.

This could be contrasted to modern biomass technical and effective use of energy characterized by high efficiency. Most of poor African population relies on traditional use of biomass for its energy uses despite the unsustainability of these trends, the rarity of quality biomass energy in these areas and the need for food security usually sourced from biomass sources [ 18 ]. The traditional uses of biomass via inefficient stoves is associated with indoor air pollution, soil degradation, forest degradation, ample time spent collecting firewood and ultimately, poverty [ 24 ].

These challenges necessitate a comprehensive analysis of biomass potential in Africa to find solutions towards having high quality, effective and efficient biomass.

The following sections discuss the various biomass types with specific production levels in Africa and thereafter the potential of biomass in the continent.

The area covered is a fifth of the continent though the distribution of this resource is uneven with the Congo Basin and some areas of central and western Africa taking the largest share as shown in Figure 2. In the regions, production of wood products and round-wood is a key source of employment and African forests account for 0. Due to the lack of recent statistics, this study used the Food and Agriculture Organization [ 29 ] data to show the forest product statistics for some African countries as shown in Table 1.

Regions of central, west, east and South Africa have larger forested and wooded regions compared to the north. This could be because the latter has a considerable share of fossil fuel resources compared to other African regions. Biomass was the largest source of total annual U. Biomass continues to be an important fuel in many countries, especially for cooking and heating in developing countries. The use of biomass fuels for transportation and for electricity generation is increasing in many developed countries as a means of avoiding carbon dioxide emissions from fossil fuel use.

Biomass contains stored chemical energy from the sun. Plants produce biomass through photosynthesis. Biomass can be burned directly for heat or converted to renewable liquid and gaseous fuels through various processes.

Direct combustion is the most common method for converting biomass to useful energy. All biomass can be burned directly for heating buildings and water, for industrial process heat, and for generating electricity in steam turbines.

Thermochemical conversion of biomass includes pyrolysis and gasification. Both are thermal decomposition processes in which biomass feedstock materials are heated in closed, pressurized vessels called gassifiers at high temperatures.

They mainly differ in the process temperatures and amount of oxygen present during the conversion process. Pyrolysis entails heating organic materials to — o F — o C in the near complete absence of free oxygen. Biomass pyrolysis produces fuels such as charcoal, bio-oil, renewable diesel , methane, and hydrogen. Hydrotreating is used to process bio-oil produced by fast pyrolysis with hydrogen under elevated temperatures and pressures in the presence of a catalyst to produce renewable diesel, renewable gasoline, and renewable jet fuel.

Syngas can be used as a fuel for diesel engines, for heating, and for generating electricity in gas turbines. It can also be treated to separate the hydrogen from the gas, and the hydrogen can be burned or used in fuel cells. The syngas can be further processed to produce liquid fuels using the Fischer—Tropsch process.

A chemical conversion process known as transesterification is used for converting vegetable oils, animal fats, and greases into fatty acid methyl esters FAME , which are used to produce biodiesel.