Charcoal factories are an important part of your city’s economy. They provide the Charcoal that is used in many of your buildings and is required to keep your resource production buildings running at full efficiency. The Mint buildings responsible for producing gold, also require Charcoal. So if you want to get more gold in Rise of Empires: Ice and Fire, make sure to keep your Charcoal Factories supplied with Lumber, and you will be well on your way to a prosperous city.