According to Science Daily, chloroplasts move around the cell by circulating in response to external factors such as light, temperature and nourishment. Chloroplasts use a small portion of the light energy that they absorb from natural sunlight to fuel movement.
Any energy that chloroplasts do not use for themselves goes to other parts of the cell that need energy. Chloroplasts are the plant's equivalent of the mitochondria that are present in mammalian cells. Science Daily says that chloroplasts "are organelles found in plant cells and eukaryotic algae that conduct photosynthesis." Their function is unique among the many organelles found in the individual plant cell.