Why does coal burn faster than wood?

There is very little water in charcoal, and therefore there is no energy expended in heating water from liquid to gas.

Charcoal is a kind of pre-burnt, which means that many stages of combustion have already taken place. “Fire” is actually a complex set of reactions that takes in large fuel molecules, breaks them down into smaller molecules, and then converts them into typical combustion products: carbon dioxide (CO2) and water (H2O). Thus, some of the combustion can be completed, but the final stages, which require oxygen to produce H2O and CO2, cannot.

Then, when you use the charcoal, all the setup work is already complete and you just need to follow the final steps of the combustion process. Therefore, these last steps (formation of H2O and CO2) generate the most heat.