Since then US stock markets have seen a steady drumbeat of yieldco initial public offerings (IPOs) from major renewables developers — from Pattern last year, to NextEra, SunEdison and Abengoa over the past few months — and more are on the way.

There are differences between them — for instance, some include transmission and conventional power projects — but one thing can be said for all of them: their IPOs and subsequent performances on the stock market have been hugely successful.

Importantly,