Biogas Technology in Nigeria

Isaac Nathaniel Itodo, Eli Jidere Bala, Abubakar Sani Sambo

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000521719
• Edition: 1
• Topic: Tecnologia e ingegneria
• Subtopic: Risorse energetiche rinnovabili

This book provides comprehensive and simplified coverage of fundamentals of biogas such as production, purification, storage, methods of improving yield and utilization, types, construction, design and operation of biogas plants. It covers stepwise design and a manual for construction of biogas plants including a planning guide, profitability analysis and evaluation of biogas plants. The biogas energy profile in Nigeria is exclusively covered.

Features:

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• Explores planning for biogas plants as a pre-requisite to develop a functional plant balancing energy production and consumption.

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• Gives out detailed provision of the types of substances that are and can be used for biogas production covering animal, municipal, and industrial wastes.

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• Provides knowledge for aspiring biogas producers as well as decision makers, specifically in the context of Nigeria.

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• Covers use of digestrate for anaerobic digestion as a waste treatment method and on the input (feedstock) to the biogas plant.

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• Compares carbon dioxide emissions from biogas plants with fossil fuel plants.

This book aims at Graduate Students and Researchers in Agricultural, Environmental, Chemical, Civil and Energy engineering and related professional audience.

1 Biogas as a Renewable Energy

DOI: 10.1201/9781003241959-1

1.1 Renewable Energy in Nigeria

Renewable energy (RE), commonly referred to as non-conventional energy, is an inexhaustible energy that derives from the sun. The earth receives 95 billion MW of energy from the sun, which is about 95 million typical sized nuclear power plants. On a clear day, the insolation reaching the earth is about 1000 W/m². This value is influenced by atmospheric conditions, the earth’s position in relation to the sun, and obstruction at the location. The justification for the increasing use of RE is the increase in consumption of crude oil compared to production, which at current production will result in its complete depletion in a few years.

The use of RE is driven by governments of the world, providing favourable policies to accelerate the dispersal and deployment of RE technologies (RETs). The most successful government policies on RE include feed-in-tariff, tax incentives/rebate, tax relief, RE credits/carbon credits and interest-free loans and financing. The production of energy from renewable sources is increasing. The common types of RE in use include solar, which can be thermal or photovoltaic, wind, and biofuels: bioethanol, biodiesel and biogas.

Nigeria currently distributes about 3,000 MW of electricity for consumers which is far less than the estimated 36,000 MW required. Nigeria thus has a huge electricity deficit that cannot be met from the existing hydroelectricity sources. Nigeria’s electricity consumption of 18,140,000 MWh/year (12.2 W/capita) is ranked 71st in the world, which is only better than Chad (178th), Equatorial Guinea (179th), Guinea Bissau (184th), and Sierra Leon (185th) and lower than Algeria, Morocco and South Africa. The electricity consumption per capita in Nigeria is 135 kWh/capita, which compares poorly with the world and Africa’s averages (Figure 1.1). Nigeria currently generates a theoretical 3,900 MW of electricity while the demand is estimated at over 36,000 MW. There is, thus, a shortage of over 30,000 MW that can never be met from the existing sources. Also, the problem of transmitting grid-generated electricity to the rural areas through very difficult terrains makes electricity supply to the rural communities difficult.

FIGURE 1.1 Per capita electricity consumption of some countries compared to Nigeria.

The installed capacity of biogas plants, solar electricity, solar water pumping, bioethanol and small hydro-power in Nigeria as of 2017 is 586 m³, 11.16 MW, 1.05 MW, 15.3 million L/year and 37 MW electricity, respectively (Table 1.1).

TABLE 1.1 Installed capacities of renewable energy technologies in Nigeria as in 2017

Renewable Energy Source	Installed Capacity	No. of Installations	Estimated Cost Per Wp of Installed System (N)
Solar electricity for lighting	11.16 MW (excluding private installations)	-	17,000.00
Solar water pumping	1.05 MW (excluding private installations)	888	2,314.00
Biogas	586 m^3 (including private plants)	25 plants	-
Bioethanol	15.3 million litres per year	-	-
Small hydro-power	37 MW electricity	-	-

Source: Itodo et al. (2017).

1.2 Biomass Energy

Energy is the ability to do work. Work means offering services such as lighting, cooking, heating, cooling and transporting. Energy consumption is a measure of a nation’s index of development and standard of living. It is estimated that in the world today about 1.6 billion people have no access to energy and about 2.6 billion rely on biomass energy sources for cooking. Energy from agricultural wastes is commonly referred to as bio-energy because it derives from organic materials (biomass). Typical examples of bio-energies, which are also called biofuels, are biogas, bioethanol and biodiesel. Biomass is the most renewable source of energy and is most widely used within the energy system. In Nigeria, the use of biomass for energy has majorly been for cooking and heating and not for electricity generation. The livestock population of 289.7 million generates about 61 million tonnes of waste in a year, 50% of which can generate 40 MW of electricity in a year when subjected to biological gasification. This amount of electricity represents 0.2% of Nigeria’s electricity needs. According to the Energy Commission of Nigeria’s projection, biomass will add 3,345 MW of electricity by 2025, although Nigeria presently has no single biomass-fired electricity-generating plant despite the abundance of biomass.

1.3 Biofuels

Biofuels are solid, liquid and gaseous fuels derived from organic matter. The common liquid biofuels in use are bioethanol and biodiesel, while the most popular gaseous biofuel is biogas. The global biofuel production increased by 10 billion litres in 2018 to reach a record of 154 billion litres. The USA, China and Brazil are the largest biofuel producers in the world. Biofuel output is anticipated to increase by 25% in the period between 2019 and 2024 to reach 190 billion litres.

Currently, biofuel production and its use in Nigeria is almost zero except for a few biogas plants. There is no commercial production of bioethanol and biodiesel. Forecast shows that there will be an increasing role of biofuels as anticipated due to the demand of the various energy sources (Table 1.2). The demand for RE fuels and electricity will increase from 0% to 17% in 2030. It is expected that the biofuels share of RE in transport in 2024 will be about 90%.

TABLE 1.2 Energy demand in Nigeria, breakdown by sector

Source	2010	2030	REMap 2030
Oil, PJ	341.0	1,941.0	1,619.0
Bio-gasoline, PJ	-	-	194.0
Biodiesel, PJ	-	-	132.0
Share of RE fuels, electricity	0%	0%	17%

Source: IRENA (2018).

1.4 Biogas Technology

Biogas is a methane-rich gas that is produced from the anaerobic digestion of cellulosic matter. The composition and properties of biogas are provided in Tables 1.3 and 1.4, respectively. The main interest in biogas is from Asia and the Pacific region. Biogas has had very little impact in Latin America. The West sees biogas technology as appropriate, while the Developing Countries think that it is a second-class technology. Biogas is used in Tanzania, Burundi, Cameroon, Benin Republic and Nigeria. About 150 mtoe of biogas will be produced globally by 2040, over 40% of which is in China and India.

TABLE 1.3 Composition of biogas

Constituent	Composition (%)
Methane	55–65
Carbon dioxide	25–45
Oxygen	0.1
Carbon monoxide	0.1
Hydrogen	1–10
Nitrogen	1–3
Hydrogen sulphide	Trace

TABLE 1.4 Properties of biogas

Property	Value
Heating value	22.0 MJ/m^3 (15.6 MJ/kg)
Density	1,200 kg/m^3 at atm. pressure
Combustion speed	40 cm/s
Air requirement	5.7 m^3/m^3 of air

1.4.1 Why Biogas?

Biogas technology is becoming increasingly important and acceptable for the following reasons:

1. The increasing reality of the Hubbert Peak has led to an increase in unit price of fossil fuel across the globe. The Hubbert Peak is the point of maximum production of oil. The point half of the recoverable oil that ever existed on the planet has been used. Alt...

Table of contents

• Cover
• Half Title Page
• Title Page
• Copyright Page
• Table of Contents
• List of figures
• List of tables
• Foreword
• Preface
• Acknowledgement
• Authors
• 1 Biogas as a Renewable Energy
• 2 Planning for a Biogas Plant
• 3 Economic Analysis and User Evaluation of Biogas Plants
• 4 Determining the Acceptance of Biogas Plants
• 5 Production and Purification of Biogas
• 6 Biogas Plants
• 7 Design of Biogas Plants
• 8 Construction of Biogas Plants
• 9 Operating a Biogas Plant
• 10 Biogas Stove
• 11 Utilization of Biogas and Effluent from Biogas Plants
• 12 Renewable Energy Policies and Standards in Nigeria
• 13 A Biogas Curriculum for Nigerian Schools
• Appendices
• References
• Index