Standards and certifications, as ‘scientific’ instruments of public and private governance, have recently emerged as ways to deal with growing concerns about the triple P sustainability of global supply chains for renewable energy. Focussing on a chain for sourcing ‘sustainable’ biokerosene for use by a major European airline, this article studies the practice of a pilot certification project aimed at thousands of Tanzanian smallholders who cultivate Jatropha oilseeds (one of the few known feedstocks suitable for biokerosene production). In particular, we study the tense interactions and encounters between a ‘universal’ biofuel sustainability standard, designed in an ostentatiously participatory process in the Netherlands, and the socio-ecological realities of the smallholders in Tanzania. As a result of these encounters, many provisions in the standard and certification protocols were found to constitute cases of ‘excess governance’, which made little or no sense in the Tanzanian smallholder context. At the same time, the standard was found to exhibit instances of ‘deficient governance’ leaving several critical issues outside its purview. Most importantly however were the cases where the provisions in the standard were deemed legitimate by the project’s implementers. Operationalization of these provisions in the smallholders’ surroundings however relied on major translation efforts involving significant brainstorming in Tanzania, conducting remedial research for problem-solving, and perhaps most importantly, significant improvisation in the field. As a result of this operationalization, many of the standard’s provisions had to undergo modifications that were initially resisted by the standard’s designers. These modifications may have resulted in a standard that is more aligned with the local realities encountered in a particular region of Tanzania. But other frictions, similar and different from the ones discussed in this article, are bound to crop up as this ‘adjusted’ standard moves to newer locales and encounters diverse social realities. In concluding, we call for regional or niche standardization strategies, rejecting the idea of universal standards that can be applied globally. A niche standardization strategy, while serving the intended purpose of the standards (in terms of ‘social’ and environmental sustainability), should facilitate the poorest farmers from reaping the benefits of the sustainability of their existing practices, a sustainability they cannot afford to prove ‘scientifically’.