If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:3:40

Video transcript

Corn husks burn quickly and turn to ash. These lumps burn hot like firewood, longer than charcoal, but are cleaner, greener, and less expensive than both. This is actually made from this. And I'm going to show you how. [MUSIC PLAYING] About three billion people in the world use charcoal today to heat their homes and cook their food. But charcoal can be expensive. It produces a lot of smoke when burned, and it's made from wood, which contributes to deforestation. In fact, 98% of Haiti's forests have been cut down for fuel. What we need is an alternative fuel source. Let's take a look at how charcoal is made. We have to first cut down trees for wood, which we then place in a closed vessel and deprive of oxygen. It carbonizes into charcoal instead of burning to ash. We then mix the charcoal with a binding solution and compress that into lumps called briquettes. This process creates a fuel source that works, but has its problems. So let's hack the charcoal production process to make everything about it better. Part of what makes the charcoal process so expensive is the equipment. Instead of a fancy vessel, you can make a simple kiln out of an oil drum by cutting a large hole in the top and several smaller ones in the bottom. Gather a couple of large rocks for the kiln to rest on, a lid for the top, and you have yourself a $15 kiln. We also need some kind of tool to mold the charcoal material from the kiln into briquettes. This is one of D-Lab's earlier designs for the hand press. We pour a mixture of charcoal and binder into the spout here, hammer down the piston, slide open the panel at the bottom, and the briquette pops right out. This design costs about $20 to manufacture. But the engineers at D-Lab wanted to do better. They changed the shape of the mold into a square, to make it easier to manufacture and significantly cut down on the amount of material used. This time, the mold itself is used to scoop the charcoal. Again, we hammer the piston, and the briquette pops right out. This design is easier to manufacture, it creates briquettes faster, and it only costs about $2 to make. Now that we've made the equipment less expensive, what can we do about making the fuel cleaner? If we can get all the smoke to burn off while the charcoal is being made instead of being used, we can decrease the amount of smoke released in people's homes. Leaving the kiln open for about five minutes at the beginning of the process will allow the smoke to burn off outside. So that why we cut a hole in the top of the oil drum. All right, final challenge. What can we do to make this fuel more sustainable? What if we replace the wood with something else-- something like dried corn husks or dried corn cobs, dried beanstalks, or even dried banana peels? These agricultural waste products, or ag waste would normally be discarded as trash. But we can use them to make charcoal, and poof! Your trash becomes a precious resource. And that's how you turn trash into treasure-- less expensive, cleaner burning, more sustainable treasure.