Against competition from cities such as Bonn, where the agency was founded, and Vienna, with its pool of well-connected diplomats, the emirate seemed a long shot.

The argument that IRENA should be based in a developing country seemed ­undercut by the fact that Abu Dhabi’s per-capita income is on a par with that of The Netherlands.

Moreover, the agency’s intention to become a beacon of green light in a smoggy world seemed ill-served by Abu Dhabi’s status as one of the world’s leading oil-producing states.

In