vanadium batteries - the good ol' days

http://www.theage.com.au/national/power-to-the-people-20111027-1mlym.html

A lament for Australia's pathetic support for commercializing new technologies (Sounds like not only the original Pinnacle/Federation attempted battery but the suceeding Gen2 and Gen3 batteries also failed to get commercial).

I am curious as to why the vanadium battery is so difficult to commercialize given that the zinc bromine battery being sold by ZBB has been (comparatively) so successful.