CHAPTER TWO: LITERATURE REVIEW 2.0 Introduction The accelerating pace of climate change has catalyzed global interest in sustainable energy systems. Central to this transformation is the shift from fossil fuel-based energy systems to renewable sourc

## CHAPTER TWO: LITERATURE REVIEW ### 2.0 Introduction The accelerating pace of climate change has catalyzed global interest in sustainable energy systems. Central to this transformation is the shift from fossil fuel-based energy systems to renewable sources, a process integral to carbon emission reduction. This chapter synthesizes theoretical and empirical studies to provide a comprehensive understanding of how renewable energy contributes to mitigating greenhouse gas emissions. Key focus areas include definitions, types of renewable energy, relevant theoretical frameworks, empirical evidence, and socio-economic implications. It also includes challenges in transitioning to renewables, as well as conceptual frameworks that can guide future research in this domain. ### 2.1 Defining Renewable Energy Renewable energy refers to energy harnessed from resources that are naturally replenished on a human timescale. These include sunlight, wind, rain, tides, waves, geothermal heat, and biomass. Unlike fossil fuels, the extraction and use of renewables typically result in negligible or zero net carbon emissions, making them critical to global decarbonization strategies. The United Nations Environment Programme (UNEP) articulates that the adoption of renewable energy systems is vital not merely for environmental benefits but as a means to access clean energy and create resilient economies aligned with the Sustainable Development Goals (SDGs). Numerous definitions highlight the multi-dimensional aspects of renewable energy, ranging from its physical resources to social, economic, and policy contexts (Söderholm & Klaassen, 2007). ### 2.2 Types of Renewable Energy The following review highlights specific types of renewable energy, their operational mechanisms, and implications for sustainability: - **Solar Energy**: Captured through photovoltaic (PV) cells or solar thermal systems, solar power offers scalable solutions for both grid-connected and off-grid applications. The International Renewable Energy Agency (IRENA, 2021) reports that global solar capacity has doubled since 2018, further supported by decreasing costs and technological advancements. - **Wind Energy**: Generated through the kinetic motion of air, wind energy has become increasingly competitive in cost and efficiency. According to the Global Wind Energy Council (GWEC, 2020), the global installed wind capacity has grown significantly over the past decade, supporting job creation and investment. - **Hydroelectric Power**: This energy form harnesses water flow through dams or rivers to generate electricity. The World Commission on Dams (2000) discusses both the ecological impacts and benefits, noting that hydroelectric power can offer reliable power supply while also supporting regional conservation initiatives. - **Biomass**: Biomass energy is produced from organic materials such as agricultural residues, wood, or animal waste. While combustion releases CO₂, it is often considered carbon-neutral if feedstocks are sustainably managed. The FAO (2018) has highlighted biomass as an important factor for rural economies. - **Geothermal Energy**: By tapping into subterranean heat, geothermal energy provides a continuous base-load power source with minimal emissions and land use. The potential of geothermal energy is discussed extensively in reports by the Geothermal Energy Association (GEA, 2020). ### 2.3 Theoretical Frameworks #### 2.3.1 Transition Theory Transition theory explores how socio-technical systems evolve over time. Geels (2002) posits that energy transitions involve complex interrelations between technological innovation, institutional change, and user behavior. This theory helps illuminate systemic changes that must accompany the large-scale adoption of renewable energy, framing transitions as multi-level processes influenced by external shocks, policy changes, and market dynamics. #### 2.3.2 Decarbonization Pathways Decarbonization frameworks such as those established by Rogelj et al. (2018) provide scenarios illustrating the trajectory to net-zero emissions across different sectors. These models underscore the necessity of renewable energy integration, emphasizing that synergy with energy efficiency improvements and robust carbon pricing mechanisms is vital for decreasing carbon footprints. #### 2.3.3 Life Cycle Assessment (LCA) Life Cycle Assessment (LCA) is a cradle-to-grave evaluation technique that assesses the environmental impact of a product or system. Renewable energy technologies exhibit significantly lower lifecycle emissions compared to fossil fuel systems, underscoring their role in sustainable development (Weidema et al., 2008). As emphasized by Gallagher (2020), LCA can reveal trade-offs and inform decision-making processes in renewable energy policy and planning. ### 2.4 Comparative Analysis of Energy Sources A comparative examination underscores the stark differences between fossil fuels and renewable energy. The Intergovernmental Panel on Climate Change (IPCC, 2021) indicates that fossil fuel combustion contributes to approximately 65% of global CO₂ emissions. This lays bare the urgency of transitioning to renewable options. Renewables, contrastingly, exhibit substantially lower emissions across their lifecycle, reinforcing their central role in achieving international climate targets. Empirically, studies affirm that different renewable energy sources vary in their emissions profiles. For example, a meta-analysis by Chen et al. (2021) reveals that while wind and solar energy bear minimal operational emissions, the broader lifecycle impacts must be continuously assessed against policy frameworks that promote sustainable practices. ### 2.5 Emission Reduction Potential In a comprehensive meta-analysis, Mason et al. (2020) demonstrate that aggressive renewable energy adoption can reduce global CO₂ emissions by up to 70% by 2050. This potential is consistent across various renewable applications—especially solar, wind, and hydroelectric—indicating that timely implementation can yield significant mitigative outcomes on a global scale. Supporting this, the International Energy Agency (IEA, 2022) projects that investing in renewables can result not only in emission reductions but also lead to enhanced energy access, thus also aligning with the goals of energy equity. ### 2.6 Socio-Economic Implications #### 2.6.1 Job Creation The labor-intensiveness of renewable technologies in manufacturing, installation, and maintenance presents significant employment opportunities. According to IRENA (2020), the sector employed over 11 million individuals globally, with expectations of substantial growth, particularly in developing regions. Studies indicate that solar and wind jobs are proliferating faster than fossil fuel jobs (U.S. Bureau of Labor Statistics, 2021). #### 2.6.2 Energy Security Diversifying energy portfolios through renewable sources enhances energy independence and security, reducing vulnerability to fuel price shocks and geopolitical conflicts (Sovacool, 2012). A shift toward locally sourced renewable energies can fortify a nation's economy and bolster energy resilience against external shocks. #### 2.6.3 Social Equity Equity concerns are paramount, especially concerning the distribution of benefits and access to renewable technologies. Wenner et al. (2021) advocate for inclusive policies that address socio-economic disparities in energy access, emphasizing that renewable energy transitions must consider marginalized communities to be truly sustainable. ### 2.7 Challenges in Transitioning to Renewables Despite the remarkable promise that renewable energy systems present, transitioning poses several challenges: - **Intermittency**: The inherent variability of solar and wind energy complicates grid management and necessitates the development of advanced storage solutions (Borenstein, 2019). Current technological innovations such as battery storage and demand response strategies are pivotal in addressing these intermittencies. - **High Upfront Costs**: Initial infrastructure and capital investment requirements can be barriers, particularly for developing economies (IRENA, 2021). Supportive financing mechanisms and international cooperation can mitigate these hurdles. - **Policy Gaps**: Inadequate regulatory frameworks and insufficient incentives can stall progress. As outlined by Smil (2016), effective policy design—including subsidies, tax credits, feeding tariffs, and carbon pricing—remains critical for facilitating a successful transition. ### 2.8 Conceptual Framework To further inform the discourse on renewable energy, a conceptual framework integrating socio-economic, technological, and policy dimensions can be established. This framework emphasizes interdependencies among various factors—policy environments influencing technology adoption rates, social attitudes shaping market acceptance, and economic implications determining financial viability. 1. **Policy Environment**: The regulatory frameworks and incentives that govern the deployment of renewable technologies, shaping market behaviors. 2. **Technological Advancements**: The innovation process driving improvements in renewable technologies and their cost-effectiveness focuses on efficiency gains and novel applications. 3. **Social Acceptance**: Public perception and attitudes significantly impact the successful adoption of renewable solutions, necessitating engagement and educational initiatives. ### 2.9 Conclusion The literature reveals a consensus regarding the transformative potential of renewable energy in carbon mitigation. Theoretical insights and empirical data demonstrate clear environmental and socio-economic benefits aligned with global sustainability goals. However, realizing this potential necessitates strategic investments, inclusive policies, and continuous technological innovation. As society grapples with the multifaceted challenges of climate change, adopting a holistic framework will guide policymakers, researchers, and practitioners in creating effective and equitable solutions in the renewable energy landscape.