A highly sustainable approach to biological hydrogen production and wastewater treatment is the microbial electrolysis cell (MECs), bioelectrochemical system. This technology is recognized for its environmental benefits, as it generates clean biohydrogen from various organic waste materials while maintaining less emission of greenhouse gas. The system utilizes an externally applied voltage to facilitate the oxidation of organic matter at the anode and the concurrent reduction of protons at the cathode. Nevertheless, the efficiency of bio-hydrogen production and the operational costs associated with MEC require further enhancement to support large-scale implementation. The transition from laboratory settings to practical applications in MEC technology has encountered several challenges. Despite the passage of over a decade since the debut of the first pilot-scale MEC, numerous initiatives have emerged to tackle these difficulties and propel the technology toward commercialization. This chapter provides an extensive evaluation of different scale-up efforts for MECs and identifies critical factors vital for their continued development. A comparative analysis of notable scale-up configurations is performed, assessing their performance from both technical and economic perspectives. Furthermore, we compiled the implications of scaling up on key performance indicators such as volumetric current density and hydrogen production rate, while also proposing strategies for system design and optimization. We find, through techno-economic analysis, that MECs exhibit the potential for profitability across diverse market conditions, independent of subsidy support. Additionally, we highlight the future developments required to promote the successful transition of MEC technology into the commercial marketplace.