Officially released live audio material is quite a tragic, sometimes also a rather ashaming aspect in ABBA's history all throughout. There even isn't a soundtrack for ABBA The Movie with complete versions of the songs used in the film.
However, there have been ideas for live albums more than once.
ABBA were considering a (double) live album release, probably for February/March 1980, but those plans were dumped by the ABBA members, apparently because of too many songs being on the album Greatest Hits Vol. 2 already. Well, whatever the logic behind this was...
In 1981 Agnetha and Frida mentioned new ideas for a live album during a Dutch TV interview, but as we know this didn't happen either.
A recent example for the weird and sad situation is that the live video snippets in the otherwise great documentary included in ABBA In Japan Limited Edition even are dubbed with studio audio. Again a chance was missed by not editing this documentary to publish some snippets at least.
2014 finally(!) saw the release of a proper live album, featuring an almost complete and unaltered Wembley concert with leaving out only the Tomas Ledin number. Hopefully this album will be joined by albums and recordings from other tours one day.
According to a schedule published in spring 2014 also a 15-minute bit of the concerts at Royal Albert Hall (1977) was planned to be released in 2014. Details about the actual content are unknown and in the end there was no such release that year. Later plans of releasing any 1977 material again were shelved. The release of live material prior to 1977 is not even rumored anyway.