Access to "essential goods and services" (g&s-ess) has become a core component of the new international agenda, enshrined in the Sustainable Development Goals (SDGs). This framework of universal access marks a turning point in development policy, characterized by the growing significance of financialization and climate challenge. It encourages the institutionalisation of g&s-ess markets, aiming to broaden access by attracting investment, fostering innovation in green technologies, and promoting a variety of market configurations on the supply side. The g&s-ess market now encompasses a wide array of actors—including financiers, multinationals, start-ups, and impact businesses—along with public-private partnerships, socio-technical systems (networks, decentralized mini-grids, autonomous systems), variety of regulation and governance regimes (public, private, cooperative, hybrid) and modes of supply and payment. Drawing on a multidisciplinary approach, the MARSE project investigates the social, political, and economic dimensions of markets for g&s-ess. By integrating international, national, and local perspectives, it critically examines the concept of universal access, especially with respect to supply inequalities at the heart of sustainability issues. The analysis zeroes in on the water and electricity sectors as representative of "essential goods", aiming to examine the particular market dynamics and the intrinsic tensions they confront (market and solvency, globalisation from above and below, responsibility and profitability, universality and inequality, centralisation and decentralisation). Based on the case of Senegal, which presents interesting characteristics regarding such changes, the research addresses four critical levels of inquiry: the evolution of international policies for universal access to g&s-ess and the escalating participation of the private sector in development initiatives; the role of public action in enacting new market regulations at the national level; the emergence of market configurations that lead to a diversity of offerings with disparities in price and service; and, finally, the public debates and local conflicts that surface due to issues of service inequality. The methodology is founded on an interdisciplinary approach that combines the sociology of markets, institutional economics, and planning sciences. It employs a multi-scalar perspective, tracking the social construction of g&s-ess markets from international levels to local implementations, alongside a multi-sectoral analysis to discern patterns of convergence within the institutional mechanisms of market organisation. The knowledge produced by the MARSE project will contribute to significant scientific debates surrounding the financialisation of public policies, sovereignty of African states, the dynamics of contemporary capitalism in the interplay between the global North and South, and global energy/water justice. The collaboration between PACTE, CLERSE, and LEREPS, coupled with the association with two Senegalese universities, reinforces the synergies between areas of expertise such as development policy, the marketization of public services, and the governance of water and energy in Africa.