This article gives some elements of definition on concepts related to the longevity of projects, infrastructures and institutions.
In the field of project evaluation and public development policies, the longevity of impacts is one of the most frequently cited criteria. It is thus one of the six evaluation criteria prioritized by the Development Assistance Committee of the OECD, translated as“sustainability” in English in the OECD glossary.
However, the use of “sustainability” requires some clarification.
The word “sustainability” has indeed acquired strong environmental, economic and social resonances since the Brundtland Report of 1987 which defines “sustainable development” as meeting “the needs of the present without compromising the ability of future generations to meet their own needs”. In this definition, the idea of sustainability relates to the absence of negative impacts for future generations, often represented by the tree-fold concept “social – economic – environmental”. Recently, the Sustainable Development Goals (SDGs) and the Sustainable Development Agenda, which refer to the 17 SDG indicators, have also broadened the scope of the word “sustainable”.

Another, neighbouring concept, is “viability”. It usually has a fairly strong economic connotation, representing the idea of medium and long-term financial equilibrium, of correspondence between costs and expenditure to ensure the survival of a company, for example. It is often associated with concepts related to economics, with expressions such as “economic viability”, “financial viability”, “commercial viability”, etc1
Finally, the word “longevity” seems to focus mainly on temporal aspects, as illustrated by this definition of the Cambridge dictionary: “living for a long time”. This definition is relatively neutral with no reference to what is “living for a long time”.
In conclusion, in this research notebook, we will use:
- the word “viability” to describe the financial, economic or commercial aspects of sustainability
- the word “sustainability” will be avoided because of its many meanings. It will be used mainly in connection with concepts such as “sustainable development” to refer to global agreements, reports and goals such as the Sustainable Development Goals. We might also use the word “sustainable” with associated concepts to describe specific aspects, such as “institutional sustainability”, “environmental sustainability”, and so on.
- the word “longevity” that will be preferred to describe, generally speaking, the continuity over time of systems, institutions, technical objects such as solar mini-grids for rural electrification.
This research notebook will tackle later related concepts such as institutionalization, routinization and ownership.
- The titles of these publications illustrate, for example, the economic connotation of “viability”:
Chakrabarty, Sayan, et Tawhidul Islam. « Financial Viability and Eco-Efficiency of the Solar Home Systems (SHS) in Bangladesh ». Energy, PRES 2010, 36, no 8 (1 août 2011): 4821‑27. https://doi.org/10.1016/j.energy.2011.05.016.
Namuli, R., P. Pillay, B. Jaumard, et C. B. Laflamme. « Threshold Herd Size for Commercial Viability of Biomass Waste to Energy Conversion Systems on Rural Farms ». Applied Energy 108 (1 août 2013): 308‑22. https://doi.org/10.1016/j.apenergy.2013.03.037.
Hossain Mondal, Md. Alam. « Economic Viability of Solar Home Systems: Case Study of Bangladesh ». Renewable Energy 35, no 6 (1 juin 2010): 1125‑29. https://doi.org/10.1016/j.renene.2009.10.038. [↩]
OpenEdition vous propose de citer ce billet de la manière suivante :
Emilie Etienne (23 août 2021). Sustainability, a multi-facetted word. Sustainability in the Global South. Consulté le 1 mai 2025 à l’adresse https://doi.org/10.58079/umpd