The California Department of Forestry and Fire Protection (CAL FIRE) Wood Products and Bioenergy Business and Workforce Development Grants Program granted Caribou Biofuels half a million dollars to deploy and optimize their mobile biomass conversion unit. The innovative biomass conversion technology will assist in processing excess fuels in forest undergrowth as well as agricultural biomass. The unit provides an alternative to burning and composting of biomass, reducing greenhouse gases and sequestering carbon in the biochar produced. We spoke with Caribou Biofuels’ CEO Kieran Mitchell, who expressed excitement about the opportunity to deploy several commercially viable installations across the state and demonstrate the impact that mobile biomass conversion can have on climate change mitigation and forest and agricultural management.
Hello! Thank you for chatting with us today. Let’s start with you telling us your name and what your role is at Caribou Biofuels.
My name is Kieran Mitchell and I’m the CEO of Caribou Biofuels. I work with a technical team of engineers and scientists developing biomass to biofuel solutions, where those biofuels can be used to generate electricity or liquid fuel. It drastically reduces greenhouse gas emissions and helps sequester carbon in biochar.
Caribou Biofuels received California Climate Investments funding to help build a mobile biomass conversion unit. Can you tell us about the machine that Caribou Biofuels has produced? What will it do and what are the different applications for it?
The machine converts biomass into high-value outputs. Often the cost of moving biomass is very substantial, so having a mobile conversion unit that can go to where the biomass is located significantly reduces the cost of operation. We pitched CAL FIRE on the project of scaling up biomass conversion to manage forestry undergrowth and then received funding through California Climate Investments. The other application is in agriculture, since they have phased out agricultural burning [in the San Joaquin Valley]. The alternative to burning as of now is often compost, which produces higher emissions than our system, so our technology is very attractive to the air districts in agricultural areas. There’s also an economic advantage to managing biomass in an environmentally sustainable way through the process of gasification. The whole point is to make an industry so that forest management and agricultural management of biomass can be economically beneficial and accomplish the goals of sequestering carbon and lowering emissions.
Caribou Conversion Technology: Inclined Rotary Gasifier (IRG). Photo courtesy of Kieran Mitchell.
Are you seeing that this machine is mostly useful for the smaller biomass material, as opposed to the larger trees that could potentially be used for lumber?
We should keep selling the larger trees that have good value for lumber. It’s all of the scrap material that has no value that this technology is designed to address.
What issues does this biomass conversion unit address? How is it uniquely suited to addressing those issues?
There are a few key factors at play: Number one is the flexibility of the feedstock. Traditional gasification systems require very dry material that would have to be processed ahead of time. This machine can process material that is wet or contains rocks and dirt, making it very adaptable to different conditions. So, on the front end, you’re reducing your cost of processing the material. Then, on the back end, you’re creating a product of higher value.
Number two is the flexibility of the outputs. We are currently producing biochar and working with the University of California, Merced to increase the value of that biochar. We are hoping to upgrade to activated carbon for an even higher value output. We are also able to produce gas that can generate electricity or be converted into a liquid fuel that can be transported off site. This technology can also be used to generate hydrogen, a clean fuel alternative. It’s a very flexible system for outputs, and it can be tailored for specific applications.
The final factor that contributes to the success of this technology is its mobility. Because it’s a modular system, it can be permitted much more easily than a large factory. The air districts are actually suggesting that we obtain one permit that applies to air districts across the state. That allows us to move and process material in communities throughout California, which is both very advantageous for our operations and appealing to local communities. Many communities don’t like big stationary facilities or factories with trucks going in and out and causing traffic issues. There is a lot more acceptance for a machine that moves in for a job and moves on. There’s also the issue of weather variability in certain parts of the state. In areas like the High Sierras that receive snow over the winter months, you can’t establish a permanent processing site. This machine is able to move above the snow line during the warmer months and process material while conditions are favorable. When conditions don’t allow for processing of forest material, the machine can then be used for agricultural operations, giving it a purpose year-round.
How were you able to make the machine portable?
One of the core factors of the design of the technology is that it’s relatively small. We have a four-foot diameter reactor that can process two tons of biomass per hour. The unit, at around four or five feet wide, can fit easily on the back of a truck that’s eight or so feet wide. We’re trying to simplify it, and the prototype is just the beginning. We expect that the next generation will be simpler, lighter, and easier to deploy.
What are the short- and long-term goals for this project? What kind of impact do you hope this project will have?
Our short-term goal is to deploy several commercially viable installations across the state so the industry can see the economic viability of this technology.
Our second goal is to establish a production manufacturing line to manufacture these systems at a low cost. To achieve that, we partnered with the largest manufacturer of agricultural equipment, Flory Industries, which is headquartered in Salida, California and has a factory up in Yuba City. The first commercial machines are going to be the most expensive, and that’s why we’re working diligently to find partners to support these first few installations, set up the production lines, and get these systems out the door. Then, once they’re up and running, we see the cost being driven down and the revenue sources being driven up. But first you have to get those first few commercial systems established. And that’s our core goal.
What has been challenging in the design, development and deployment of this technology? What have you learned from these challenges that may be helpful to others taking on similar projects?
It’s very important to be flexible. Developing new technology is very expensive and you’re going to make mistakes. Having a flexible machine that can be used for a variety of applications, whether it’s electricity, hydrogen, or liquid fuels, is a core priority. A lot of biomass systems focus solely on biochar, missing a significant opportunity on the fuels or electricity side. From our perspective, it’s very hard to justify just making biochar. Biochar is great as a soil amendment, but we also need to upgrade that to higher value outputs. Liquid fuels, electricity, or hydrogen outputs are what really put the economics of this type of technology over the top. It can’t just be focused on biochar from our perspective. You have to have other outputs, or it just doesn’t make financial sense. That’s the biggest lesson we learned.
What advice do you have for others applying for funds? Was there anything you learned through the application process that you think others should know?
Be persistent. Make mistakes. Move on. You just have to keep going and have faith moving forward.