A bomb has gone off near a disused electricity station near Zaragosa in north-eastern Spain. No one was injured.The Basque separatist group ETA had reportedly warned the Basque highway agency before the blasts but there had been confusion over where the bomb was located. The group has repeatedly targeted Spain’s electricity infrastructure in the past. It is the second bomb in four days apparently planted by ETA. A car bomb exploded at an industrial park in central Spain on Saturday in the first attack in two months by the group.