Activist: Accidents at the Three Mile Island and Chernobyl nuclear plants have shown the dangers of nuclear power. It was earlier argued that nuclear power was necessary because fossil fuels will eventually run out. Recently, however, a technology has been developed for deriving from sewage sludge an oil that can be used to generate power. This new technology, therefore, together with the possibility of using alternative sources of energy like solar, wind, and hydroelectric power, raises the hope that we can dispense altogether with nuclear power and that we can meet our energy needs in a way that better protects the environment from harm than we do at present.

Which one of the following considerations is LEAST relevant in evaluating the degree of practicability of the hope expressed by the activist above?