"The basis of (prior) calculations grew detached from real conditions," says the report. "Wind potential must be reevaluated based on the latest analytical methodology while factoring in wind power technological development of recent years and current geographical data."
The research calculates geographical area suitable for wind plant construction based on wind velocity and a variety of social conditions. A previous JWPA study, in 2007, concluded that Japan's landscapes could accommodate 81GW. The JWPA says that besides using newer, more accurate geographical survey data, the new study also adds forests to the categories of land open to development.
The new study finds that far more locations are suitable for both onshore wind and offshore wind - using turbines tethered to the seabed. The area suitable for floating turbines, a still-nascent technology, is smaller. But the assumption is that turbines of greater rated capacity will be available.
The JWPA concludes that 65GW of onshore wind is judged feasible, compared to 25GW cited in its earlier study. It also considers it feasible to install 29GW of offshore wind using tethered turbines, compared to 18GW in the earlier report. The potential installed capacity of floating turbines is 39GW, little changed from the earlier projection of 38GW.
The JWPA presents a plan for Japan to satisfy 10% or more of its electricity demand with wind power by 2050, compared to 0.3% in 2008. This calls for installation of 50GW of wind power capacity distributed across the country and comprises 26GW of onshore wind, 7.5GW of capacity from tethered offshore turbines and 16.5GW from floating units.
But current trends do not bode well. The plan's figure for installed wind power capacity is 3GW this year, the national target. But with only 2GW of installed capacity so far, Japan is likely to fall far short.