Biofuels in Circular Economy

Today’s world faces two challenges: energy shortage and environmental pollution. Fossil fuels for power generation and transportation have caused high carbon dioxide emissions (CO₂) to the environment. Renewable energy plays a vital role in the global and domestic approach to the mitigation of energy and environmental issues. Some renewable energy sources, including solar energy, wind, bioenergy, geothermal energy, hydroelectricity, and ocean energy, have a lower environmental impact than fossil fuels. In comparison with fossil fuels, biofuels are a source of renewable energy that can guarantee the country’s economy while preserving the natural climate. It appears that only microalgae can replace fossil fuels as feedstock. It's common to grow microalgae in photo-bioreactors or huge open ponds. The carbon dioxide produced due to the combustion of biofuel is recycled in photosynthesis for biodiesel production. In coal co-firing, microalgae can produce electricity to reduce greenhouse emissions and lower coal consumption. Moreover, bioethanol and biodiesel can replace two primary fossil fuels (gasoline and diesel) used in the transportation sector.

This paper describes the biofuel economy and food security in the current scenario, focusing on the competing demands for food and fuel. The biofuel economy is expected to increase rapidly in the twenty-first century. This increase may, however, disrupt the agri-food system that threatens food security. Understanding the diverse aspects of the agriculture landscape to meet the demands for food and biofuel that rely on agricultural biomass is essential to satisfy the needs of the exponentially growing global population. The concepts of industrial symbiosis and circular economy offer potential solutions to sustain the biofuel economy without putting at risk the supply of food and utilizing wastes and residues from the farm, including the refuse from food processing plants, as raw materials for biofuel generation are probable ways to optimize the overall productivity of agriculture towards addressing the requirements for food and biofuel. Also, adopting Smart Agriculture/Agriculture 4.0 is explored for the management of the entire agri-food supply chain from pre-production to post-harvest stage to sustain the biofuels endeavour without disrupting the food supply. Agriculture 4.0 can provide a holistic view of the agri-food system crucial in a circular economy to ensure efficiency in biofuel production and food security.

The current sustainable transition plans seek to pursuit energy supply security with low carbon emissions. Although electrification is presented as a key factor to decarbonize demanding sectors (transport, buildings, and industry), energy provided by fuel combustion will be essential to cope with future demands. In this sense, it is necessary to rely on circular economy models based on low carbon biofuels. During the last decade, the biofuels industry transitioned from being sustainable and socially accepted to a deeply questioned solution due to the food versus energy debate. Therefore, using alternative feedstocks, such as wastes or residual biomass, is convenient to obtain biofuels creating new value chains during the transformation. This chapter is focused on the technologies developed for biofuel production capable of minimizing the carbon footprint. Production methods for gaseous biofuels and liquid biofuels are described. The possible integration of each technology is evaluated considering the availability of feedstocks and the emission savings obtained by main biofuels (bioethanol, biobutanol, and biomethane). This analysis reveals the need for diversification in feedstocks utilization and transformation and the intensification of waste management technologies. In this sense, a case study is presented considering the most extensive wastes produced worldwide (agricultural by-products) and the potential production of regular biofuels (bioethanol, biomethane, and biobutanol). Net energy production as biofuel and emission savings are analyzed for each case. This analysis reveals that bioethanol presents the best performance in terms of carbon neutrality. Finally, a revision of the most recent regulations affecting biomass transformation in biofuels and their role in the circular economy in Europe is included in the last section. This section provides a framework for the application of the technologies and the case study presented.

Current energy strategies address environmental challenges that are efficient and eco-friendly for fulfilling the energy requirements and enhancing energy utilization more sustainably. Increasing global demand leads to depletion of natural resources, continued expansion of population globally, and industrialized economy. Primary energy demand has grown that increased gas and oil production. Increased consumption of imported oil possibly will impede economic growth. Alternative energy production is a prominent issue in the research and development market due to the increased demand for fossil fuels and the resultant impact of global warming challenges. Bioenergy derived from biomass is a long-term alternative energy source that has acquired significant support in various sectors, including government laws, industry, and the public sector. It requires support from the government, the general public, industry, and research to ensure its long-term existence. Manufacturing processes, including chemical conversion, that is an inexpensive process, large-scale production of biofuels, have not been well explored and explained in this chapter. As a result, a cost-effective and efficient production process is necessary to commercialize biomass-based biofuels. This chapter includes and covers sustainable and renewable biofuel resources, as well as biofuel commercialization milestones.

In the mid-1970s, there was an increasing interest in biofuels when Brazil and USA started producing ethanol from sugarcane, though the consumption of biofuels had started in the late nineteenth century, and developed up to 1940s.

Global population growth and economic development increase energy consumption (primarily from fossil fuels) as well as waste generation. Energy resource depletion is unavoidable, and when it occurs, biofuels may be the ones to meet society’s energy demand in the future. According to the World Energy Council, global waste generation is estimated to double by 2025 to more than 6 million tonnes of waste per day (this waste is composed of a large number of biomass materials). The management of this waste is one of the major challenges facing society for the construction of green circular societies, and for this, the use of waste and its transformation into bioenergy is fundamental. Biogas presents itself as a clear ally for the transformation of economies, obtaining environmental, social, economic and safety of supply benefits. Biogas is a fuel gas (consisting mainly of CH₄ and CO₂) that is generated by biodegradation reactions of the organic matter, through the action of microorganisms. This process is called anaerobic digestion (AD). Currently, AD is largely applied in the agro-industrial sector for its ability to stabilize organic matter by recovering biogas, hence renewable energy, and organic fertilizer from the digestate. In the present chapter, we will define the concept of biorefinery applied to Two-Phase Olive Mill Waste (TPOMW) to demonstrate that it is a technically feasible and economically viable project in itself. In this case, there is another added environmental advantage: the joint industrial complex enters fully into the concept of Green and Circular Economy, thus closing the cycle of organic matter and applying the paradigm: “from waste to resource”.

To meet the ever-increasing energy demand, human society is reliant primarily on petroleum-based fuels in today’s environment, notably in the transportation sector. The high rate at which fossil fuels are used and subsequent emission into the atmosphere promote the concentration of greenhouse gases to rise. Biofuels are undoubtedly one of the most trustworthy alternatives for long-term transportation and economic improvement. E-fuels, solar fuels, and microalgal fuels can be strong next-generation sources for reducing the devastating environmental effects of conventional fuels. This article focuses on the history of the shift from conventional fuels to biofuels and the usage of biofuel as a viable option for long-term development.

Biofuels are getting attraction as an alternative to fossil fuels due to their environmental benefits and their renewable nature. Consumption of oil derivatives in combustion engines and boilers has increased carbon dioxide, resulting in the global warming effect. Besides this, oil production is reaching the near-term peak, and the subsequent decline in production has been already detected. The world production of liquid biofuels, mainly ethanol and biodiesel, has increased by over 160 billion litres (equivalent to 4 Exajoules). In addition, the production capacity of other fuels such as biomethane, biobutanol, bioethanol and biomethane is continuously increasing. In the transport sector, biofuel is a real alternative to fossil fuels with a contribution of just over 3% today. Indonesia, the USA and Brazil are the largest producers with more than 40% of the global production. Germany and France in Europe are increasing their production with a strategy based on biomethane. A case study is presented considering the economic revenues of the transformation of the most widespread agricultural wastes into the most promising common biofuels.

Bio-economy is a primitive economic sector, and an increasing bioenergy production by biotechnology transforms to the newest one. Renewable biofuel is the keystone to the current and future bio-economy. Mainly, bio-economy is termed as a set of economic activities connecting the invention, development, utilization and production of biological products and processes sustainably without lessening their availability for future generations. In most developing countries, the nexus between biofuel and bio-economy is crucial in gross domestic product (GDP) and employment. The Organization for Economic Cooperation and Development (OECD) mentioned that an advanced bio-economy would drive potential shifts in the global economy over the next 30 years. Still, renewable biofuel production has a positive and negative nexus with the development of the world’s bio-economy. The positive aspects of biofuel include proper utilization of biological resources, greenhouse gas mitigation, food security, job opportunities, poverty alleviation and human health improvement. Contrariwise, the negative aspects of biofuel involve biodiversity loss, indirect land-use change, forest alteration, water scarcity and pollution. Recently, negative impacts of biofuel expansion are specially marked as large constraints for globally sustainable bio-economic development. Governments of many countries have established participatory governance, policies and different financial initiatives toward achieving bio-economic sustainability by reducing constraints. In between 2000 and 2010, global biofuel yields increased sixfold, and a growing number of countries are taking bioenergy promotion policies. Private–public partnerships (PPPs) are also expected to be implementing incentives and innovative technologies for concerting sustainable development of biofuel and the bio-economy. In view of this, the current book chapter focuses on the relation between the increasing productivity of biofuel production and bio-economic development.

Biorefinery is a sustainable tool to generate manifold bioenergy products along with valuable biomolecules by utilization of relevant conversion technologies. Since the last decade, there is high attention on green concepts like bio-economy and circular economy for eco-friendly sustainable development. Recently, the conjoint economy concept known as circular bio-economy has come up to the light. It is with the prominence of holistically marking the environmental, economic, and social aspects of the industrial sector. In this context, a biorefinery could act as an effective tactical mechanism by adapting the realization of a circular bio-economy. This chapter gives a comprehensive overview of the bio-economy, circular economy, and the conjoint circular bio-economy. It illustrates different biorefinery models and the adoption of biorefineries in a circular bio-economy. It also describes the biorefinery framework for adapting circular bio-economy and methodology for assessment of biorefineries’ sustainability and information of biorefineries w.r.t. circular bio-economy. It focuses on the strengths and weaknesses of the biorefineries w.r.t. circular bio-economy. Furthermore, it highlights some challenges and magnificent recommendations for the adoption of biorefineries in a circular bio-economy.

The renewable biofuels invention has caught substantial attention worldwide over the last decades. Edible and non-edible sources of biofuels have witnessed major changes in the approaches in the form of three generations. The first-generation biofuels, refer to liquid fuels derives from starchy food crops and vegetable oils, and these are the renewable energy sources. The second-generation biofuels are liquid and gaseous fuels from non-food crops such as lignocellulosic biomass. Biofuels comprised of algae; and other photosynthesizing microorganisms are named as the third-generation biofuels. Biofuels production is crucial in improving environmental, economic and social sustainability. Recently, in developed and developing countries, biofuels utilization has increased significantly as it ensures economic security through poverty reduction. The major biofuel producing countries in Asia are China, Indonesia, India, Thailand and Malaysia. In these countries and in poorer nations, the biofuel expansion is an additional income source and employment generating opportunity. Therefore establishement of biofuels production industry has the potential to reduce poverty and increase rural welfare by injecting new economic activity. For example, a bioethanol industry in Mozambique is estimated to create around 56000 jobs directly through feedstock and processing activities by 2025. Moreover, innovations in biofuel industries are having a direct benefit to farming community especially women who are involved in biomass production activities. At present, biofuels development creates gender empowerment, improves land rental values, increase income, minimizes oil price, lowers transportation costs and reduces electricity cost. However, the biofuel production is a  contentious issue and demands investment in research and development for achieving the economic security for the poor. In view of its projected opportunities for sustainable energy production coupled to accelaration of economic security and reduction of poverty, we have focussed on a detailed narration on this globally relevant topic.

The concerns of escalating greenhouse gas (GHG) footprint and fast dwindling stock of fossil fuels have given impetus to the alternate sources of energy and production processes by adopting a circular economy, optimally utilizing all aspects of wastes. The microalgal refinery can use the complete waste stream, secondary recycled products, and co-products while producing biofuel. Unutilized biomass can be converted into electricity through combustion. Biofuel from microalgae is emerging as a viable liquid fuel to satiate the growing demands of the transportation sector. Microalgae are metabolically versatile microorganisms with the scope of viable feedstock in the biofuel, nutraceutical, pharmaceutical, and cosmetic industries. Microalgal refineries have the potential to mitigate waste through efficient biomass processing for energy, polymers, food additives, nutraceuticals, bioactive compounds, co-products, etc. The objectives of this chapter are to (i) assess the economic viability of decentralized microalgal refineries along the Indian west coasts and (ii) audit algal refineries considering all possible pathways for microalgal biomass. The analyses considered costs associated with (i) cultivation, (ii) harvesting, (iii) processing and extraction of biofuel, and (iv) processing of residues towards minimizing waste and ensure circular economy with the extraction of value-added products. The techno-economic (TE) analysis results demonstrated an estimated yearly profit ranging between ₹ 35,296 INR/ha and 209,190 INR/ha, depending on the level of external inputs during algal cultivation. The production cost of biodiesel with crude glycerol and biogas as the value-added products varied between INR/kg and 59.52 INR/kg of biodiesel with an estimated payback period of 0.98–2.97 years. The last section of the chapter presents the scope for a diverse mix of products towards a circular economy.

Recently, waste to energy projects regained international interest due to environmental concerns and sustainability agenda oriented to reduce waste generation while using these materials as feedstocks to produce low carbon energy. Biodiesel is a renewable fuel derived from vegetable and animal triglycerides. It is obtained through a transesterification reaction between a triacylglycerol and alcohol in the presence of a catalyst. Nowadays, the primary commercial feedstocks are edible vegetable oils. However, waste cooking oil (WCO) and residual fats are alternative feedstocks that can also produce biodiesel. They are available at a reasonable cost in urban areas, where food processing residues, either from residential, commercial, or industrial sectors, are relevant sources. These feedstocks have the lowest carbon emissions per litre of produced biofuel compared to fresh oil biodiesel. In 2019, the Mexico City government launched a Sustainable Energy Strategy to increase the contribution of renewable energies in its energy matrix. Particularly, in the case of the transport sector, the government has promoted, in alliance with Academic Institutions and public companies, the production of biodiesel from WCO to be consumed as a B10 blend in a pilot program for public transport. This model is expected to maximize the environmental, economic, and social benefits from the production of biodiesel since the four steps of the life cycle system would be located at the city perimeter, minimizing transport and distribution burdens. Thus, this chapter analyses the Biodiesel Program for Mexico City as a case study of biodiesel in the circular economy.

The application of circular economy has positioned as one of the pillars of the sustainable global agenda through the insertion of waste biotransformation into a variety of high-value compounds such as biofuels, which significantly reduce the concerns associated with environmental pollution such as the generation of greenhouse gases and final disposal expenses. In this context, the production of biofuels using lignocellulosic biomass is attractive since they are generated in large volumes, as well as the minimization, generation, treatment and disposal of wastes. This review addresses the sustainable production of biofuels through the use of microbial consortia in consolidated bioprocesses (CBP), presenting advantages and drawbacks of the use of synthetic microbial consortia (e.g., those designed by different mechanisms such as genetic modification) against native consortia (NC) isolated from different ecosystems to reduce costs and residence times. In addition, challenges and current perspectives to apply NC towards the generation of biofuels are comprehensively revisited since these consortia present excellent stability and resistance to change in environmental conditions or system disturbances. This offers an outstanding capacity to biodegrade numerous biomass resources (i.e., substrate), since they split complex metabolic tasks to achieve a remarkable performance, replacing the metabolic design representing a cutting-edge option for CBPs implemented in a sustainable biorefinery to generate biofuels in order to potentiate the use of biomass in the circular economy.

Over the last two decades, global biofuels production has grown significantly. While several types of renewable biofuels exist, the significant share consists of ethanol and biodiesel. The biofuels trade is mainly driven by the adoption of greenhouse gas (GHG) emissions reduction policies by the developed countries, including the U.S., E.U., and Brazil. Among several renewable fuels, biofuels are considered to have diverse environmental, social, and economic impacts. Therefore, the biofuels industry in general needs to consider the importance of these factors while evaluating the future perspective of biorefineries. On a global scale, the current and future issues, including energy security, food security, rural development, agriculture and industrial policy, trade, and GHG emissions reduction related to biofuels, need to be considered. Policies always drive biofuel production, use, and trade. Given the importance of policy within the biofuel industry, this chapter summarizes country-specific policy objectives, instruments, and priorities—case studies of major biofuels producing countries are presented as a critical element. We find that while ethanol trade and production have faced more targeted policies and tariffs than biodiesel, the future of biodiesel trade will depend on how the importing countries implement the sustainability requirements. Domestic ethanol use has been saturated in the USA as it hits the gasoline blending capacity. Thus, in the future the U.S. ethanol demand will depend on export market, and how the foreign countries adopt their domestic biofuels use mandate. Competition from other global ethanol producing countries, particularly Brazil can not be ignored too.