This is a 2-kg coffee roaster powered by a 150 gasifier. This unit paid for itself in less than one hour of operation. It uses less than one-watt hour of electricity per kg of coffee beans. The gasifier uses waste biomass such as rice hulls and coffee husks as fuel.
It is easy to combine the roasting of coffee with the making of biochar. A gasifier/roaster can be used to roast green beans, and as it does so, it makes a beautiful biochar. Coffee shops in many places throughout the world could use gasifier/roasters and could save a lot of money.
In the case of commercial grade coffee beans, one kg of roasted beans sells for about 6 times more than one kg of green beans. In the case of specialty grade coffee beans, one kg of roasted beans sells for about 10 times more than one kg of green beans. Furthermore, when the magnificent aroma of coffee being roasted fills the air, this makes a great advertisement for a coffee shop.