Much of the generating capacity to meet the needs of the future may be from generating stations in groups of two or three, each of 1000 Mw, located away from the growing urban areas. Transmission systems will become longer and be of higher duty; and a combination of popular demand and land cost will force the system underground at increasing distances from cities. The need for higher capacity cables to match the new overhead systems and for reduced capital and installation costs is forcing the search for better materials and new techniques. The vast size of the power industry implies that a breakthrough in technology would have dramatic consequences and even a small improvement in materials or techniques can be of significant economic importance.