The couple will spend their anniversary at a self-catering cottage after a day of official engagements.
Assad al-Nassasra was missing for weeks following last month's attack, in which 15 emergency workers were killed by Israeli troops.
However diversified Spain's energy mix is, the blackout required an enormous effort to get back up and running.
The company not saying who carried out the attack - or when their systems will be restored - suggests it's serious.
The author's new book The Rose Field will end the His Dark Materials and The Book of Dust trilogies.
The 38-year-old posted online before the planned violence and listed his targets.