Fuel

There are various types of fuel available to use in Factory Town:

Many Buildings require fuel in the recipes such as the Forge and Kitchen

In this picture below you can see an example of recipes in a Forge(old). It displays that to make 1 iron plate you require a fuel value of 2.

This means that you would need 2 Fertilizer, or 1 Wood every 4 seconds.

For the Gold Ingot recipe you would need 4 Fertilizer, 2 Wood, or 1 Coal every 8 seconds.