In cells, ATP is the “currency” of energy transfer. ATP is created by the processes of glycolysis (does not require oxygen) and oxidative phosphorylation (requires oxygen). read more
They get energy from Adenosine Triphosphate. Which in simpler terms is one Adenine molecule and 3 phosphate groups. This energy is produced by the sugars or carbohydrates that you consume, and then get turned into energy for your red blood cells. read more
The way, functional red blood cells produce energy is by fermentation, via anaerobic glycolysis of glucose followed by lactic acid production. As the cells do not own any protein coding DNA they cannot produce new structural or repair proteins or enzymes and their lifespan is limited. read more