The article states: "By 2020 Japan plans to place 140 wind turbines to produce over 1 gigawatt of electricity."
Then later says: "Harnessing wind in deeper waters off Japan could generate as much as 1,570 gigawatts of electricity, roughly eight times the current capacity of all of Japan's power companies combined."
I don't know if it is true but lets make some assumptions in their favor. The best data I could find on off shore wind farm capacity factors (ie the percentage of name plate power they produce over a year) was as follows: offshore wind – Minimum: 27%; Median: 43%; Maximum: 54%
Now this was from a pro wind power website. I will be generous and say they operate at 60% power all the time which is unrealistic but please bear with me. It says 140 wind turbines for over a GW so it is probably just barely over but I will say 100 turbines per GW power. That is 157,000 wind turbines at 5MW a piece operating at 100% CF at 60% it is almost 262,000 % MW wind turbines. To be fair they also said that is 8 times what Japan currently produces but it is unclear if that is what is being produced now or before Fukushima. I will give the benefit of doubt again and say before. They would still need 33,000 5MW wind turbines. This would take almost 80 years based on the best year for installing wind turbines in the EU at 418 in 2013. Then we can talk about the cost of the transmission cabling to get power from all the turbines on shore from tens of miles off shore, not to mention how would they survive a 30 meter Tsunami although the wave would be less in the deeper water. I fully believe that wind power is a part of a solid mix for electrical production but putting all the eggs in one basket has proven a bad thing throughout history. Stop hard selling and just disclose all the issues whether they are technologically difficult or expensive. People will decide to accept things if they are informed upfront.