Gather up agricultural leftovers, blast them with pyrolysis (high heat, low oxygen), and what you get is a crumbly, black matter that could save the world. Making biochar generates clean energy, and at the same time sequesters carbon dioxide in a charcoal-like substance that just happens to work fertile wonders on crops and gardens. Jason Aramburu is the young whit behind Re:Char, a fledgling startup developing micro-scale reactors, which he hopes to see pumping out biochar on every continent. (He also provided TreeHugger with a special report on mountaintop removal last June.) Jason was a Social Innovation Fellow at this year's Pop!Tech conference, which is where we caught up with him and got the scoop on biochar and his new venture.
Special thanks to Pop!Tech for making this interview possible.
Full text after the jump...TreeHugger: So what the heck is biochar?
Jason Aramburu: Biochar is very similar to the charcoal that you find in your barbeque grill except that biochar is made from waste, things that are left over after we grow food, things like husks, pits, stalks, leaves, even waste wood. We make biochar by taking that biomass, the waste, and heating it up in the absence of oxygen, and we get this charcoal product. We also get a lot of energy. It's an exothermic reaction, which means it's really hot. So our technology harnesses that energy and makes power.
TreeHugger: If I were using your technology and setting out to make biochar, what would the process look like, what would I do, and what would come out the other end?
Aramburu: The first step is to collect your waste. Most farmers are already collecting this kind of waste--they might mulch it or compost it. So you take that waste and the first step is you need to get it down to the right consistency. So it's got to be very fine particles. We use some mulching and threshing equipment to get the waste down to the right size, then we process it in our reactor. That converts it into the char and a fuel product, which we use to run a generator.
That's how they generate power. They take that biochar and actually put it back on their fields, actually burying it about six inches in the ground. And by doing that, you can both sequester atmospheric carbon and improve crop yield. So the biochar actually acts as a great soil amendment.
TreeHugger: So it's good for crops?
Aramburu: Good for crops, gardens, forests, everything.
TreeHugger: So the type of stuff you put in, can it be food waste like actual scraps, or does it have to be an industrial agricultural by-product?
Aramburu: Well, it can be any kind of biomass. The main consideration is the moisture content. The drier the feed stock, the drier the stuff you put in, the better. Food wastes tend to be very wet and soggy, so if they can be dried with air drying or solar drying, then it's a possibility.
TreeHugger: What does this mean for the amount of carbon dioxide in the atmosphere?
Aramburu: This has potentially huge applications. If we can scale it, get it out there in large enough quantities, we can take a huge amount of CO2 out of the atmosphere. The way to think about it is this: we're growing plants--they take CO2 out of the atmosphere--and then we turn them into charcoal. By doing that we immobilize that carbon on the earth in the form of biochar so that it can't get out.
We're finding that the carbon in biochar has a residence time of at least 2,000 to 2,500 years. That's what we can identify so far. If you bury that, it's not going to get back into the atmosphere anytime soon.
TreeHugger: Even if it is used as an amendment for a crop that's being harvested, tilled, trampled around on by livestock, it's still sequestered? It's still stuck in the ground?
Aramburu: Exactly. Even in disturbed agricultural soils where you're constantly turning over the soil, it still stays in the ground.
TreeHugger: This is a private company, Re:Char, so why the approach to make it for-profit versus a non-profit venture?
Aramburu: Well, we think a big driver to develop technologies is the notion of profit. To get investors, they want to see a return; they want to know that the business is sustainable and that it can sell itself. We think if we're going to really convince people about the importance of carbon mitigation, they also need to see it in their pocketbook. For a technology company it's hard to get investors on board if you're non-profit. We think that being for-profit allows us to have the greatest reach and the greatest expansion possibility.
TreeHugger: What's an example of a real-life community that would be getting financial and ecological benefits from a process like biochar?
Aramburu: An ideal community would be a small farming village in Africa where they're likely off-grid, so they don't have grid power, but they have a need for the power. They want to run their lights, they want to run their cell phones, maybe they want to run refrigeration equipment for food and medicine. These are sites where they're producing just the right amount of biomass. In general, these farms are about one or two acres in size. With several of them aggregated, that's plenty of biomass to feed the reactor. It's also producing enough power to meet their needs.
On the biochar side, it's producing enough biochar that they can reduce their dependence on chemical fertilizers.
TreeHugger: Compare this to a technology like solar. If a village were to install a photovoltaic system to supplement their energy needs, how does something like that compare to the pros and cons of using biochar?
Aramburu: Solar is great, and renewables like solar and wind are obviously crucial to reduce the emissions we're putting out. But there are a couple of problems with solar. Number one, you need a storage mechanism if you want to use the power at night, which in most cases you do. You need batteries or some way to store it. The same with wind: the wind only blows at certain times.
Another issue with solar is cost. It's still pretty expensive. And then finally, waste is a big problem. Using pyrolosis to make biochar, you actually dispose of the waste.
Then perhaps most importantly, solar is not going to do anything for the carbon we've already put out. We're at about 387 parts per million of CO2 in the atmosphere. Most scientists like James Hanson are saying we need to get down to around 350.
To do that in a reasonable amount of time we have to go beyond carbon neutrality. We have to be carbon negative, so actually sequestering carbon.
TreeHugger: If a village like you mentioned were to invest in your reactor, what are they looking at spending?
Aramburu: At this point we're still in the pilot stage so we're just developing and iterating the technology, validating that it works. We believe that we can achieve cost parity with traditional biomass, which is already on the low end of clean tech.