Hywind is a test run, but the benefits for perfecting floating wind-farm technology could be extremely large. Out at sea, the wind is often stronger and steadier than close to shore, where all existing offshore windmills are planted. Deep-sea farms are invisible from land, which helps overcome the windmill-as-eyesore objection. If the technology catches on, it will open up vast areas of the planet’s surface to one of the best low-carbon power sources available.

1. The Hywind project uses totally new technology to ensure the stability of¡¡¡¡¡¡.¡¡

A. the cables which tie the spar to the ocean floor

B. the spar which is floating in deep-sea water

C. the blades driven by strong and steady sea wind

D. the stones filled in the spar below the sea surface