Global energy demand has risen sharply, intensifying concerns over greenhouse gas emissions and climate change. Fossil fuel combustion remains the primary driver of increasing carbon dioxide levels. A rapid transition to clean energy sources is therefore imperative. Dark fermentative biohydrogen production (DFHP) has been investigated as a scalable, low-carbon hydrogen (H2) pathway that leverages organic waste and industrial waste heat. The study objectives were to quantify research evolution, assess techno-economic performance, and propose sustainable deployment pathways. Bibliometric analysis was performed on 435 Scopus records, yielding an annual growth rate of 19.6 % and 928 unique keywords. Besides, bibliometric trends were visualised using VOSviewer, Biblioshiny, and Graphica software. For techno-economic evaluation, H2 conversion efciencies, water requirements, and cost impacts under waste-heat integration were compared against conventional H2 production methods. DFHP was shown to operate in standard fermenters with negligible water demand. Wasteheat integration was demonstrated to eliminate external heating costs and lower levelized H2 costs. Key technical and operational challenges were identied, including feedstock variability, volatile metabolite inhibition, and mass- and heat-transfer limitations at scale. Sustainable pathways were outlined, emphasizing low-energy pretreatment, in situ metabolite removal, advanced reactor geometries, and inclusive capacity-building partnerships co-located with waste-processing facilities. Alignment with sustainable development goals (SDGs) for affordable clean energy, responsible consumption, and climate action was highlighted. A clear roadmap has been provided to advance global decarbonization efforts and to accelerate the deployment of a resilient H2 economy.