Energy-producing organelles are the

Cells responsible of making energy and performing respiration within the cell. Depending on what type of organism they are found at, they can be known as Mitochondria, if they are in animals; and if they are in plants, Chloroplasts.
Mitochondria create energy for the cell by breaking down sugars, fats, and other fuels consumed by the cell.
Chloroplasts, on the other hand, since they are found at plants, convert sunlight into energy.

Yes he thought they should be left to chance why, because he thought that was the best thing to do