Algae-derived biofuel production and opportunites for sustainable bioenergy in Nigeria

Table of contents

Abbreviations and acronyms

Units and symbols

CHAPTER ONE INTRODUCTION
1.1 Nigeria and Its Resplendent Energy Profile
1.2 Kyoto protocol and the Nigerian renewable energy policies
1.3 Nigeria Action on Renewable energy
1.4 Renewable Energy in Nigeria
1.6 History of algae biofuel
1.6 Status of algae in biofuel generations
1.7 Diversity and suitability of algae
1.8 Classifications of algae strains
1.9 Biology and chemical compositions of algae

2 CHAPTER TWO PRODUCTION OF ALGAE BIOMASS
2.1 Open System
2.2 Closed Photobioreactors (PBR)
2.2.3 Types of photo bioreactor systems PBR
2.3 Heterotrophic Fermentation
2.4 Integrated Cultivation Systems
2.4.1 Biofilm Processing
2.4.3 Algal Turf Scrubbers (ATS)
2.5 Advanced Integrated Wastewater Pond System
2.6 Heterotrophic Fermenters
3 Processing of algae to biofuel
3.1 Harvesting and moist removal
3.2 Algal oil extraction
3.3 Conversion of oil to algae derived biofuel

CHAPTER four 4 SUSTAINABILITY OF ALGAE DERIVED BIOFUEL
4.1 Element of algae derived sustainability
4.1.1 Energy protection
4.1.2 Economic Structure
4.1.3 Environmental and resource control
4.1.4 Social affiliations
4.2 Indicators
4.3 Life-Cycle Assessment of Algae derived fuel
4.4 Scenario Analysis

CHAPTER FIVE ECONOMIC IMPLICATIONS OF ALGAE BIOFUEL
5.1 Alternative revenues

CONCLUSIONS

REFERENCES

Abbreviations and acronyms

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Units and symbols

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CHAPTER ONE INTRODUCTION

Algae, a group of living organisms uniquely adapted to aquatic environment; they exhibit conversion ability of radiation energy into carbon source aimed at reducing emission from conventional fuel. The most assured interest of algae as a biofuel agent is the abundance storage of lipid which is converted to various energy yields (Posten and Schaub, 2009).

Civilization, urbanization and competition of tillage land with crops for production of bioenergy have been among the challenges facing the bioenergy sector. However, an excellent panacea is the cultivation of algae from waste, non-waste water or industrial waste water, which has been found to be a positive platform for algae-derived biofuel (Kazamia et al, 2012); numerous attempts have been made by so many nations to reduce carbon emissions; amongst are the developments of frameworks for the prospective utilization of renewable energy resources, due to its abundance and sustainability. There is no gainsaying that countries in African are endowed with renewable energy resources, especially Nigeria. Lack of expertise, inadequate management and failure to adhere to policies has been a great challenge in actualizing the promising benefit of renewable energy and implementation in Nigeria (Nwulu and Agboola, 2011).

According to Ladokun et al (2013), Nigeria is a tropical rich zone which lies between latitudes 4°N and 14°N and longitudes 2°2’E and 14°30’E, it occupies wide coverage of 923 770 km2. Owing to its hydrological potentials which are considered as great assets to the algae biofuel energy industry. The country is a coastal region with boundaries along the southern area by the Atlantic Ocean. The country’s north-south part extents to about 1 050 km and its east-west extent is about 1 150 km, which is bordered to the western part by Benin Republic, also to the northern region by Niger and Chad, also boarded in the eastern part by Cameroon (Nkwunonwo and Okeke, 2013).

1.1 Nigeria and Its Resplendent Energy Profile

Nigeria is potentially productive in algae-derived biomass production due to its enormous strain of algae species, abundant water and solar radiation resources (Figure 1), which lead to green sources of energy.

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Figure 1: Map of Nigeria showing radiation across regions

Source: (SOLARGIS, 2011).

However, technological know-how has been a great challenge in Nigeria, coupled with political interests which have also been significant factors, especially with the country’s giant stake in the Organization of the Petroleum Exporting Countries (OPEC) forum. Nigeria is a country known for its large oil production with ranking among the first fifteen world’s largest oil-producing countries, this accounted for 96% of export value earnings and more than 75% of the federal government revenue of Nigeria in 2012 (EIA, 2013). About 90% of government income is sourced from over dependence on the oil sector which has negatively affected other prospective energy generation sectors.

In the African region, population of the country is around 166.63 million inhabitants in 2012; the country is a potential resourceful base for algae-derived fuel production with aquatic capacity of 221 000 km3 per volume per year in 2011 for freshwater availability. The aquatic hydrological resources are yet to be fully utilized, but utilization capacity of 31.45%, 52.44%, and 15.07% for domestic, agricultural and industrial usages have been observed respectively (FISHSTAT, 2013).

Nigeria is a highly favorable region for algae production, algae requires different condition which has made it realty in Nigeria. Climate resources in form of temperature, sunlight and proximity of season’s availability are justification for algae availability in the country. Figure 2 shows temperature zones in different continents; according to APEC (2011), 15°C of temperature or more is required for algae culture. Based on figure 2, the temperature of Nigeria, shown with a oval shape in the map falls around 30°C and 35°C, hence algae production is potentially viable for the Nigeria.

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Figure 2 Annual average temperatures of world zones scaled in Centigrade and Fahrenheit

Source: Climate Charts (2007)

1.2 Kyoto protocol and the Nigerian renewable energy policies

Climate change challenges have been a great global factor which has impacted negatively on humans and other creatures. All these have been attributed to Greenhouse Gas (GHG) emissions. Numerous natural cataclysms have been caused by it, however at the global level, outstanding and proactive commitment has been made in order to mitigate the effects. A common global direction of environmental protection through sustainable development of natural resources for the future has been the motive of several international policies on environmental protection and sustainable development. The most salient policy that addresses environmental protection in lieu of GHG emission reduction is the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) (Akanbi et al, 2012).

It consists of five main elements aimed towards the limitation of greenhouse gas (GHG) emissions and actively adopted by many developed nations. The protocol recommended three flexible mechanisms namely: International Emission Trading System (IETS), Joint Implementation (JI), and Clean Development Mechanism (CDM) in order to enhance the obligation of the agreed emission criteria (Anger, 2008).

Nigeria is an Organization of the Petroleum Exporting Countries (OPEC) nation; it belatedly became a signatory to the Protocol, however becoming the first OPEC nation to fully ratify the law. The Country ratified the UNFCCC and the Kyoto Protocol in August, 1994 and December, 2004 respectively (Climate Investment Funds, 2010). While on the 10th of March 2005, it finally entered the agreement into force.

There were possibilities and potentials for the country to benefit from the market-based mechanisms given by the treaty to achieve the targets by Annex 1 countries, ranging from gas utilization projects to development projects (Okafor, 2011). The Annex 1 countries are nations considered to be industrialized, including countries whose economies are averagely formidable and some other European countries. According to Hirschl (2009) the Kyoto protocol did not prominently address renewable energy, although green energy from renewable sources are among numerous solutions to environmental protection as well as ensuring sustainability of global resources. Apparently, algae-derived fuel is a type of renewable energy; it is also a potential cross point for Kyoto protocol because of the common motives of the consequence and mitigation practice which is evident in their mandates.

1.3 Nigeria Action on Renewable energy

According to Climate Investment Funds (2010), after showing strong commitment to the contribution of environmental protection, the Federal Republic of Nigeria domesticated the international commitment into its local policies. Therefore, producing its first national communication under the framework and convention on climate change in November, 2003. This largely recognizes potential opportunities for climate mitigation and adaptation.

On July 22, 2009, the Nigerian Senate passed a bill to establish the National Climate Change Commission as a statutory body and to vest with the responsibility to regulating and coordinating policies including actions on climate challenges. The commission planned to create a carbon market scheme and tackle the negative impact of global warming on Nigeria. The motives behind the strategic development of the Nigerian Energy sector are: to provide economic and commerce-driven incentives to attract private investments (local and foreign), hence facilitate the required energy capacity expansions in an emerging economy; to consolidate reforms of structural and economic interest for the creation of an efficient institutional and regulatory frameworks in the energy sector; to create secured supply of energy adopting the nation’s renewable energy resources to compliment energy usage.

1.4 Renewable Energy in Nigeria

The Nigerian Energy Master Plan (EMP) was launched in 2006 and identifies considerable potentials for generating green energy across the country. Pilot projects have been identified, and scaled-up. Therefore recognizing the potential of providing clean electricity from renewable energy, especially to Nigerians living in areas not served by grids, with the potential of about 100-200 MW within 5-10 years period. A major element of the strategy is to reduce greenhouse gas emissions without jeopardizing the economic motive for development. This is important to establish and generate a structured and viable domestic markets which promote the usage of clean natural gas for productive uses in the power sector, including the use of Liquefied Petroleum Gas (LPG) for cooking and other domestic purpose, also in the transportation industry as Compressed Natural Gas (CNG).

Nigeria is known as the most populous African country that is grossly enriched with abundance of renewable energy resources including biomass (another form of algae-derived fuel resource). The Renewable Energy Master Plan (REMP) (2005), recognizes abundance of sunlight resources, a great requirement for algae production, with annual average daily solar radiation of 3.5 kWh/m2/day in the Southern region and 7 kWh/m2/day in the northern arid region. The value of the sun would greatly support great algae production. The region is also endowed with river basins for water availability and usage. There are about 11 river basins, which is flows across the country in all geographical locations namely. The River Basins are in the regions of Anambra-Imo, Benin Owena, Chad River, Cross River, Hadejia-Jama’are, Benue River, Lower Niger, Niger Delta, Ogun-Osun, Upper Benue and Upper Niger River, Sokoto-Rima. The run off flows of the rivers is evidently seasonal. More than 160 dams are in Nigeria for agriculture electricity generations and water supply for communal and domestic use (Akanmu et al 2007). The potentials are not only limited to inlands waters, however there are abundant aquatic opportunities in the marine environment of the Country. In line with boosting the renewable energy interest, the plan of the renewable energy plan was based on the National Economic Empowerment and Development Strategy (NEEDS) and the Millennium Development Goals (MDGs) which is now replaced by the Sustainable Development Goals (SDGs). This was envisioned by the National Energy Policy (NEP) on renewable energy, also promoted by the 2004 international commitments of world leaders in Bonn, Germany to spurt the utilization of renewable energy and develop opportunities for sustainable energy in Nigeria and the globe (REMP, 2005).

In a renewable perspective, the motive of the Nigerian renewable energy plan is to address national problems through simulative development and manipulation of renewable energy. This has enacted renewable energy policies, legal framework, technologies and commercial strategy to ensure actualization of its motive. The motive of the plan was to ensure sharing of energy supply through renewable energy and also the improvement and development of various energy technologies. Algae-derived form of energy is yet to be included in the energy plan, however categorized in the biomass section (REMP, 2005).

1.6 History of algae biofuel

According to Spolaore et al (2006), historic tribute to algae production has been pioneered with the cultivation of microalgae beginning in 1960s in Japan by Nihon Chlorella, where Chlorella spp was cultured. The use of algae for energy production has been initiated due to the 1973 inadequate supply of fossil fuel, which eventually became a crisis, although different from the motive to mitigate CO2 release purportedly, the research was funded by Exxon Research and Engineering Company (Williams and Laurens, 2010).

In the United States of America, around 1978, a unique programme for algae production called Aquatic Species Program (ASP) was launched under the Department of Energy with financial commitment of $25 million, afterwards the project was terminated due to inadequate funding in 1996 (Sheehan et al, 1998). At the end of the ASP research, algae-derived biofuel promised to be an appreciable alternative pathway when compared to other biofuel programmes with great success in its biology, culture, biotechnological engineering and species categorization. A Japanese programme on algae biofuel was activated at a cost of $100 million but with little success. Around the late twentieth century an organized extensive algae research facility arranged in New Mexico, USA, however concluded that reduced cost of production of algae-derived biofuel was analytically feasible based on the report, it was later recommended that there is need for more research in order to overcome the high productivity challenges affecting alge biofuel (Mata et al, 2010). In 2007, the global algae biomass production was around 10 000 tons, 50% of the production has been from China, while countries such as United States of America (USA), and some other nations including Australia also contributed to the remaining half (Kanes and Forster, 2009). In late 2015, algae production for renewable energy began in South Africa at the Nelson Mandela Metropolitan University (NMMU).They combine algae grown in ponds with waste from coal to produce a coalgae fuel which has been tested with negative environmental impacts, they are presently planning a large scale use.

1.6 Status of algae in biofuel generations

According to Veillette et al (2012), first generation of biofuels are majorly derived from edible consumed food stuff, such as vegetables, sugars, oil producing plants. Due to sustainability concerns, these foodstuffs show various limitations namely; inadequate land availability and reduction of fertile land for production. For more effective biofuel biomass utilization, the second generations of biofuels adopt the use of non-edible foodstuff to produce cellulose based biofuel. The biofuels generated bio hydrogen, wood diesel, bio alcohol and bio-oil. Third generation of biofuels uses algae and microorganisms to produce bio diesel, jet biofuel, vegetable oil etc.

Carbon neutrality and reduction of non-anthropogenic carbon dioxide is one of the benefits of the two later biofuel generations, although according to Christi, (2007) a ton of algae biomass deplete about 1632.93 kg of carbon dioxide while first generation reduce greenhouse emission by percentage around 41%. Algae biofuel production is highly advantageous compared to other biofuel products. Based on Kanes and Foster (2009), CO2 is one of the major requirements for algae production, one ton of algae requires about two tons of CO2, and capable of producing about one ton of oxygen, this evaluation can successfully bio-refine around 3.5 barrels of biodiesel; the carbon dioxide from various fossil operations can be a beneficial input to the algae production. In addition, some algae such as red algae (Chondria armata), green algae (Stichococus bacillaris), Chlorella vulgaris, can absorb harmful hazardous metals, nitrogen oxides and sulphur oxides emissions (Skowronski and Ska, 2000).

1.7 Diversity and suitability of algae

Selection of algal strain is highly necessary in biofuel production, all over the world there are about 300 000 species (Stott et al, 2010). Nigeria is well-endowed with algae species both micro and macro algae, which is attributed to ecological richness of the tropical environment. The country is highly diverse in algae species; there are different strains of the species which are suitable for algae fuel production. According to Onyema, (2008) it is reported that the following algae species are predominant in Nigeria: Chlorophyceae group; a total of ten species were recorded for the green algae namely: Akistrodesmus spp., Cladophora glomerata, Gonatozygon monotaenium, Gonotozygon spp., Microspora flocci, Straurastrum paradoxum var cingulum, Pediastrum simplex, Spirogyra africana, Scenedesmus obliquus and Scenedesmus quadriqauda. In the country, overabundance of algae are more in the dry season than in the wet season because of the unrestricted growth of algae in the tropical region. Over Ninety strains of species have been reported in the coastal region of the country especially in Lagos lagoon (Onyema, 2008). According to Akin-Oriola, (2003), abundance of some specific algae species have been observed in Nigeria: the blue-greens (Cyanophycea e) Microcystis aeruginosa, green algae (Chlorophycea e) and Pediastrum boryanum.

There are 10 taxonomic groups of algae which are great strains for algae derived biofuel; the green algae (Chlorophyceae), diatoms (Bacillariophyceae), yellow-green (Xanthophyceae), golden algae (Chrysophyceae), red algae (Rhodophyceae), brown algae (Phaeophyceae), dinoflagellates (Dinophyceae), Prasinophyceae and Eustigmatophyceae (Hoek et al, 1995; Williams and Laurens 2010). According to NRC, (2012), the following algae are of great importance to algae-derived fuel: diatoms (Bacillariophyceae), Green algae (Chlorophyceae), golden-brown algae (Chrysophyceae), prymnesiophytes or Haptophytes (Prymnesiophyceae), and eustigmatophytes (Eustigmatophyceae) as illustrated in Table 1.

Accumulation of lipid increases with different categories of algae strains under many conditions, according to Singh et al (2011), based on international standard, the alkyl ester in lipid determines the efficiency of the biofuel, although induced biotechnological techniques such as omics (proteomics, genomics or metabolomics) methodologies are highly obtainable in the future to improve strain constituent suitable for algae production; sunlight; nutrient and iron content which are major accumulating factors for better biofuel strain. All these contribute to the quality of oil used for biofuel production. Species of algae which are high in lipid contents are mostly important for biodiesel production, algae species with high carbohydrate in form of starch are usually considered for ethanol production, and species whose highest compositions are heat are mostly used in the bio-power industry to produce electricity. Some algae species are highly important in the biotechnological and biochemical industry to produce nutraceuticals (nutrition and pharmaceutical), useful foods, dye products and production of pigments used to enhance vitamins e.g. β-Carotene C40H56 (Kanes and Forster, 2009).

Table 1 Features of Algae with possibilities for biofuel.

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Source: NRC (2012)

Photosynthetic efficiency in form of sunlight has also been regarded as a tool for algae production; it will in turn enhance their sustainability, although it is a way to differentiate different algae strains. Another differentiating tool is resistance to external environmental constraints like competitions, pathogens, salinity, temperature and pH. The rigidity of algae to withstand harsh conditions is considered to be a great factor in choosing a very good strain. According to Tillman (2004), algal species with large cell walls are likely to be more resistant to predation than unicellular strains. Ability to survive in every climatic situation has proven worthy for strain collection. Harvesting as a criteria for algae strain selection has also been reported by Tang et al (1997), algae with forming ability have better chance of harvest which subsequently do not require centrifugation because of their floating ability and ability to be meshed out of the crop.

1.8 Classifications of algae strains

According to Kanes and Forster (2009) algae are classified based on structures and biological life cycles, some of the classes are listed below:

- Diatoms (Bacillariophyceae): they are unicellular algae species predominantly considered to inhabit the oceans. Some of the diatoms are euryhaline; they can be found in reduced saline waters or middle saline aquatic environment, about 10 000 000 of the species can be cultured in 1mm of water i.e. 10 percent of water volume. The size ranges from about 5µm to 5mm in size. They store carbon in form of oil or chryrsolaminarin.
- Green Algae (Chlorophyceae): They are unicellular algae which exist as colonies; they can survive in low saline environment with highest temperature for production considered to be around 32°C. Starch has been considered as their form of carbon stored in the cell.
- Blue-green Algae (Cyanophyceae): The blue-green algae are known as a eurythermal type of algae. They have the capacity to survive at temperature between -60°C and 85°C and have been considered to be freshwater organisms; they also play a key role in nitrogen fixing processes and have the ability to grow in any kind of illumination condition.
- Golden Algae (Chrysophyceae): They are mostly freshwater species. The golden algae are known for their shiny varieties of colors, they have advanced pigment system and store appreciable amount of lipid and starch.

1.9 Biology and chemical compositions of algae

Numerous algae exist in nature, their suitability for algae culture depend on the lipid quantity (Sheehan et al, 1998). Algae species contain substantial quantities of lipids with oil yield (Table 2).

Table 2 Lipid contents and productivity of different microalgae species.

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Adapted from (Mata et al 2010).

According to Mata et al, (2010), Chlorella spp is a good prospect for biofuel production; however factors to be considered for selection include development of the algae strain under available nutrients, environmental conditions and fatty acids composition.

Algae species consist majorly of lipids and they procreate at a faster rate. According to Christi (2007) growth rate of multiplication are up to 3.5 h. They are unicellular organisms with capacity to photosynthesize and are highly abundant in the Nigerian environment, their habitat ranges from higher marine to lowest freshwater habitat (Falkowski and Raven, 2007). A typical algae is composed of organelles embodied by double layers of molecules. They are composed of four major biochemical molecules namely: carbohydrates, proteins, nucleic acids and lipids (Mata et al, 2010).

Table 3 Biochemical constituents of typical algae.

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Adapted from (Williams and Laurens, 2010)

As photosynthesis is a peculiar process of algae formation, carbohydrate is the key product of formation, including different constituents of monosaccharides and polysaccharides. Up to 50 percent of the dry weight of algae is made of carbohydrates (Dismukes et al 2008).

Algae consist of commonly known polysaccharide, the chrysolaminarin, found in the chloroplast (Mata et al, 2010).

For the rapid growth of algae, the protein operates in a structural and metabolism functions, they support the chlorophyll in the chloroplast. Lipids serve as energy reserves for cells. The simple fatty acid triglycerides are important energy reserves. The lipid constituents are deducted from fatty acids components and molecular structure. The calorie values are estimated based on the higher heating values which are similar to bomb calorific value. The calorific values of protein and nucleic acids are derived from values of their component molecules (Williams and Laurens, 2010). Calorific value of biofuel is averagely lower in biofuel than fossil fuel, the calorific value represents the value of heat used during combustion which is a function of energy in the biofuel.

High energy considerably indicate high calorific value in the fuel. These values are important for fuel users because of energy transferred in engines (Oliveira & Da Silva, 2013).

2 CHAPTER TWO PRODUCTION OF ALGAE BIOMASS

There are several systems of algae production all over the world, some of these production systems are motivated by the need for fuel and other useful products. Water, land or space, carbon dioxide and light are essential nutrients. The level of management also contributes to the environmental effects. From inception, the evolution of algae production creates the open and closed systems including the Photo bioreactor (PBR). Different media has emanated due to research and technological advancement. Hence, various differentiated pathways systems namely, the hybrid systems, closed photo bioreactors, heterotrophic fermentation, and integrated bio fixation systems have been developed and are currently in use (Ryan, 2009).

2.1 Open System

Open systems are set of simple and cheap cultivation systems; they are mostly done using open ponds, outdoors compartments or controlled houses. They are constructed in circular lagoons, or raceway. The raceway is commonly used for extensive commercial algae production due to their open nature; they absorb radiant light from sunlight. Algae in the open system pond are sometimes nourished with sewage water from waste water collection systems; this reduces the cost of sewage disposal or recycling plants. It also requires a small amount of power because algae requires mixing to enhance growth; therefore activated pedals with the aid of a motor is used, the power can also be minimized with solar energy.

It is easy to maintain. Most of the open ponds are made of concrete in order to avoid seepage, motors are usually kept up to avoid waste accumulation, and constant exchange of water is required to control the high temperature which vaporize water from the pond. Based on a typical design of an open pond for algae production, the specifications below show dimensional measurements:

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