Power cables have been connected to all six reactors at Japan's damaged nuclear plant, a significant step in bringing the complex under control.
In making the announcement after days of anxious waiting by the public, the Tokyo Electric Power Company warned that much needed to be done before the electricity can be turned on.
Workers are checking all additional equipment for damage to make sure cooling systems can be safely operated.
In another advance, emergency teams dumped tons of seawater into a nearly boiling storage pool holding spent nuclear fuel, cooling it to 50C, Japan's nuclear safety agency said.
Steam, possibly carrying radioactive elements, had been rising for two days from the reactor building, and the move lessens the chances that more radiation will seep into the air.
Added up, the power and concerted dousing bring authorities closer to ending a nuclear crisis that has complicated the government's response to the catastrophic earthquake and tsunami that devastated Japan's north-east coast 11 days ago.
The Fukushima Dai-ichi nuclear complex has leaked radiation that has found its way into vegetables, raw milk, the water supply and even sea water across a band of Japan.
The resulting fears of radiation mean the impact has reverberated well beyond the disaster area and the families of the hundreds of thousands of displaced and of the estimated 18,000 dead.
"We must overcome this crisis that we have never experienced in the past, and it's time to make a nationwide effort," Chief Cabinet Secretary Yukio Edano, said in his latest remarks meant to soothe public anxieties.