Economical tidal energy

The fundamental technology needed for large-scale electricity generation from tidal energy has long been available, but the execution of such projects presented problems of scale which became practicable only relatively recently. In the last few years, changed circumstances and the continuing refinement of schemes put forward have brought the prospective costs of tidal energy utilization into the area of serious commercial interest. The objective must be to achieve the most economical result which calls for an appreciation of the range of alternatives open, and of the important variables. Equally, there is need for proper definition and understanding of terms like "economical" and "optimum", as applicable in different contexts. The fluid and uncertain future prospect for power generation costs is warning enough that as criteria and methods of commerce and engineering have changed in the recent past, still more will they change in the future.