Regarding the May 26 article "Renewable energy quest to tap ocean-based sources": I am delighted that the government is planning to tap ocean-based energy sources. I fear that the article does a disservice in calling out wind power as an example. Tides and temperature differences are much more predictable.

Japan has another renewal energy source in abundance: geothermal. The Japan Times has many times noted objections to geothermal based on the need to build in national parks. If one looks to the Dinorwig pumped-storage hydroelectric plant in Llanberis in Wales' Snowdonia National Park, one can see that this does not have to be a problem. The power station is built inside a mountain and the transmission lines are buried to the boundary of the park, 9 kilometers away. Nothing is visible.

Dinorwig's purpose is to level the load by pumping water to an upper reservoir during off-peak hours (or times when the wind is blowing) and letting it drop back through the turbines during peak times. Japan has geography well suited to this type of facility, which would be a useful adjunct to both renewable and nonrenewable power sources. I think Japan's construction industry would love giant projects like building power stations inside mountains and, for a change, the money would be well spent.

The opinions expressed in this letter to the editor are the writer's own and do not necessarily reflect the policies of The Japan Times.

mark callow