Was Crocodile stronger at Marineford? Or was he holding back in Alabasta?

 During the Alabasta arc, Crocodile displayed a level of power that was initially considered overwhelming by the Straw Hat Pirates. He possessed the Logia-type Devil Fruit called the Suna Suna no Mi (Sand-Sand Fruit), which granted him the ability to control and transform into sand. He had a reputation as a Shichibukai and controlled the desert kingdom of Alabasta from the shadows. His strength was showcased through his battles with Luffy and others. At Marineford, Crocodile was present as part of the war that took place at Marine Headquarters. While he did participate in the battle, he didn't display the same level of dominance as some other powerful characters present. This has led fans to speculate that he might not have been as strong as initially portrayed in Alabasta. It's important to note that power scaling and character abilities can be subject to interpretation and development by the author. Oda often keeps details deliberately open-ended to keep the story intriguing.

How many people in the world depend on coal for their energy needs?

 It is difficult to estimate the exact number of people in the world who depend on coal for their energy needs, as the use of coal varies significantly from country to country and region to region. However, it is safe to say that a significant portion of the global population relies on coal to some extent for their energy needs. According to the International Energy Agency, in 2019, coal accounted for 27% of global primary energy demand and 38% of global electricity generation. This means that a significant portion of the global population relies on coal-fired power plants for electricity, which is a crucial source of energy for many households and businesses.

It is also worth noting that the use of coal for energy has been declining in recent years due to concerns about its environmental impact and the availability of alternative sources of energy. Many countries are transitioning away from coal and towards cleaner sources of energy, such as renewable energy sources like solar, wind, and hydroelectric power.