The problem with nuclear's use of water is that the water released is heated and causes problems with the ecosystem (ie, waste heat). In fact, Diablo runs at a

The problem with nuclear's use of water is that the water released is heated and causes problems with the ecosystem (ie, waste heat). In fact, Diablo runs at a lower power to prevent dumping too much waste heat back into the ocean ecosystem. From the wikipedia page: " and power is limited during operation so that water returned to the ocean is no more than 20 °F (11 °C) warmer than ambient temperature. "