By Osamu Tsukimori TOKYO, Oct 30 (Reuters) - Nine Japanese power plant operators posted 717.5 billion yen ($5.9 billion) in net profit in April-September, thanks to a $4 billion boost from low fuel prices, but their full-year outlook is precarious amid prolonged nuclear plant shutdowns. A halving in crude oil prices since June 2014 helped utilities cut fuel import costs by a third, or nearly $10 billion, while power revenues have not fallen as much because it takes three to five months for the effect of falling fuel prices to be passed on to electricity bills. Tokyo Electric, effectively nationalised after an injection of public funds following the Fukushima disaster, posted a record-high recurring profit of 365.1 billion yen, up 50.4 percent on year, helped by a 221 billion yen boost from the time-lag effect as fuel costs declined by $3.6 billion. "We got lucky on the first-half results from the time-lag (effect)," Tokyo Electric President Naomi Hirose told reporters. "This is temporary, and profits are not an underlying trend." Of the 43 commercial reactors in Japan, only two reactors run by Kyushu Electric have resumed power generation. The eight other nuclear operators are still struggling financially despite the rate hikes they resorted to in the face of increased fossil fuel costs amid nuclear shutdowns. Kyushu Electric on Friday posted net profit for the first time in five years in the first half of its fiscal year, helped by the restart of the Sendai nuclear plant. Average household power fees have declined only about 5 percent since June 2014 to around $63 a month despite cheaper fuel, partly because of the time-lag and partly on a doubling in the surcharge charged to support renewable energy projects, to more than $3.40 per month. The following table shows the power companies' net profit/loss results for the six months ended on Sept. 30 in the business years 2014/15 and 2015/16. Figures are in billion yen.

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