Give counter examples. Nuclear energy powers the Sun. Sunlight is energy source for plants, which decompose unto coal, for gasoline, for example.
Plants also feed animals and feed people, for one form of chemical energy.
Sunlight evaporates water which forms clouds which rain more water,and so on. Running water is then used in hydrolectric power. Sunlight heats the Earth unevenly, eventually generating wind and waves which can be harnessed to make electricity. Discuss why or why not. Yes, their densities could differ.