Final answer:
Nuclear energy is the alternative energy source least dependent upon weather, providing consistent, reliable power independent of external conditions. Geothermal energy also has low weather dependence but nuclear typically has higher capacity and broader implementation.
Step-by-step explanation:
The alternative energy source expected to be the least dependent upon the weather would be nuclear energy. Unlike solar and wind energy, which are subject to the whims of weather patterns and daylight hours, nuclear power does not depend on external weather conditions. Nuclear reactors can produce electricity continuously and are considered baseload power sources due to their ability to consistently supply power without interruption. While natural disasters can pose risks to nuclear power plants, the actual operation of a nuclear plant and its energy output are not typically affected by day-to-day weather.
Geothermal energy is another alternative energy source with low dependence on weather. It harnesses heat from within the Earth, which is both abundant and constant, meaning geothermal power plants can operate all year round without significant impact from weather conditions.
Therefore, comparing the two, nuclear energy would generally be less affected by the weather compared to even geothermal energy, because while both are non-intermittent, nuclear plants are often built to a capacity that can far exceed the energy generation of geothermal plants and are more widespread as a global energy source.