Your beautiful and well maintained lawn can be one of the best carbon sequestration devices in existance. Lawn grass, because of its abundance, captures more ambient CO2 than any existing or proposed technology. The plants in home landscaping are well watered, well fed and well cared for (generally) and grow at optimum rates, which means optimum carbon dioxide uptake. If this captured carbon dioxide can be diverted and sequestered the power of this resource can be realized. Well now it can.
How? By converting your weekly yard waste into biochar using your backyard BBQ. Once your yard waste has been reduced to its native carbon it can be bagged and disposed of ease with the trash, added to your compost heap or buried in that old family Cold War era bomb shelter.
Now that summer is here most of will be mowing the grass and firing up the BBQ. For those of us with a charcoal BBQ the leftover coals can be put to good use. I haven't tried with a gas grill yet, but I will. What we're going to do is make a simple biochar reactor and use the BBQ, some charcoal and a small fan to turn it into biochar.
Here's some helpful hints:
hint #1: Don't be an idiot. Make sure you produce more charcoal than you burn.
hint #2: Check your local burning regulations
hint #3: This stuff is hot, really hot, be careful
Step 1: Bill of Materials
Biochar is produced by combustion of organic material, normally plant material, in the abscence of oxygen. To do that we going to take a steel can and drill some holes in the side. Then we're going to fill the can up with grass trimmings and seal it up. Then we're going to heat it up and see what happens....
Okay, you're going to need a lawn...or yard waste from a lawn...
Also you'll need a backyard charcoal BBQ with a cover. I'm using a small Weber brand for the proof concept. The cover may be optional, I remember a traditional style BBQ with a wind shield. That could work as well since the wind shield will capture the fan breeze.
A method for lighting the charcoal. I'm using petroleum based charcoal lighter fluid. I've seen the starters cans that use newspaper and they work pretty well. I may get one....
A small fan. I'm using a standard electric fan but I recommend a small battery powered fan with a solar recharger.
A steel can with a lid. I'm using a 1 gallon paint can I picked up at my local paint store for $2. It will do for this purpose and fits inside the small Weber. The can must have a lid which can be secured in a way that will withstand heat. I've got an idea for another reactor design I got from homedistillers.org I will update this if that works out. To scale up use a full size Weber kettle and a 5 gallon paint can from the paint store.
A drill and drill bit for drilling ventilation holes in the steel can. This will vent the methane and other gasses produced into the fire where it will be consumed.
Okay with all of that we're ready to start....