(UPDATE-2) Common Spent Fuel Pool cooling is scheduled to resume at 8AM on March 20.
(UPDATE) Jiji Tsushin reports that TEPCO hopes to resume cooling of the SFPs of Reactor 3 and Reactor 4 at about 8PM (Japan Time). (It's about 3:45PM in Japan now.)
Information from NHK Kabun (Science and Literature) tweet, about 20 minutes ago:
At about 2:20PM on March 19, power was back on at Fukushima I Nuclear Power Plant. Cooling of Reactor 1 Spent Fuel Pool resumed.
No information about other Spent Fuel Pools or other facilities. No details as to what caused the power failure to begin with.