This review evaluates the feasibility of using microalgal culture for sustainable energy production, emphasizing microbial fuel cells (MFCs) and biophotovoltaics (BPVs). This study’s uniqueness is rooted in its thorough examination of recent developments (2014–present) in microalgal strain selection, bioreactor design, and electrode materials. Furthermore, this review combines microalga cultivation with wastewater treatment, highlighting its importance. Notably, it examines advanced methodologies, such as the use of genetic engineering to enhance microalgal traits, nanotechnology to optimize electrode efficacy, and artificial intelligence (AI) to optimize bioelectrochemical systems. In addition, this study identifies possible future research avenues by examining microalga–bacterium consortia and cascaded biobattery systems. Consequently, the incorporation of case studies illustrating microalga biobatteries’ practical applications in low-power devices and wastewater treatment underscores the technology’s promise. Similarly, this study examines significant problems with enhancing farming methods, reconciling cost and yield, and integrating renewable energy sources with the grid, offering vital insights for academics and policymakers. Ultimately, this review emphasizes the need for economical cultivation methods, waste stream utilization, and scalable bioreactor designs, thereby considerably advancing sustainable energy options.

Microalgae are becoming increasingly identified as a novel solution for the production of clean electricity. The chapter discusses their twin function as biological solar panels and biochemical factories, being highly capable of using sunlight and waste feedstocks to produce sustainable energy. The chapter starts with a description of the biological characteristics that render microalgae particularly suitable for energy applications, including energy-rich macromolecules and light-absorbing pigments. In addition, emerging cultivation methods—from open ponds to sophisticated photobioreactors—are assessed for their potential to optimise growth while, at the same time, reducing the use of resources. The following chapter presents a comparison and contrast of two varied electricity generation approaches: direct systems exemplified by microbial fuel cells utilising bioelectrochemical processes and indirect systems that transesterify algal biomass to biodiesel, biogas, or hydrogen for energy use. These technologies have in-built environmental benefits, for example, wastewater treatment and carbon sequestration from industrial exhausts. Despite this, there are still difficulties in the sustainable economic development of the technologies, most conspicuously in balancing energy input and output and optimising large-scale agronomy. Future developments in genetic manipulation and bioreactor technology are expected to increase both efficiency and cost-effectiveness. This chapter outlines the potential of microalgae to enhance renewable sources of energy, alongside addressing critical issues of the environment. It does this by reconciling key concepts in science and practical implementations and thus presenting a motivating vision towards sustainable development for the twenty-first century.