Answer to Question 1
There is a real danger that OTEC could affect climate. That is because we are
extracting energy from exchange of cooler underlying water with warmer surface water and
thus bringing cooler water to the surface. The temperature difference between the surface
and the cooler lower layers of water is important for driving the ocean conveyor that
circulates surface water from near the north pole and rises again. Cessation of the conveyor
would seriously alter climate, especially in northern Europe.
Answer to Question 2
Each dam is built in place, so that is not a place for economies of scale to act. It is
hard to see, in fact, how economies of scale could possibly work in dam construction.