Siskiyou County Multi-Benefit Biochar
Scott River Watershed Council
How can biochar produced using mobile carbonator technology reduce the carbon emissions of fuel reduction projects while benefiting the local landscape and economy?
This project tested the economic feasibility of biochar production on a commercial scale as a way to address healthy forest management, reduce carbon emissions and smoke, as well as sequester carbon. Biochar is a stable form of carbon that can be sequestered in the soil for decades, if not longer, and can improve soil health by increasing water holding capacity and fertility. Using a Tigercat mobile 6050 carbonator, woody biomass generated from nineteen acres of a shaded fuel break and hazardous fuel reduction project was converted to biochar. The biochar was then distributed to five local ranches for use as soil amendment. By creating biochar locally for local use, this project connects the need for hazardous fuel reduction in the uplands with the fertility of the agricultural lands in the valley bottoms.
Project Overview
Fuel management is greatly needed across the state and North Coast region. Pile burning and chipping are common strategies to process the woody biomass produced from hazardous fuel reduction projects. However, pile burning releases greenhouse gasses and creates a smoke hazard for local communities, and chipping is often cost prohibitive due to the transportation costs of trucking woodchips to a processing or cogeneration plant. Biochar production provides an alternative to these strategies that has multiple benefits to the land and the community.
Project Goals
- Determine economic feasibility of carbonator technology with local markets and feedstocks
- Convert woody biomass from hazardous fuel reduction project into value-added biochar
- Distribute biochar to agricultural producers for use as a soil amendment
- Introduce production and use of biochar at multiple scales to the region through community outreach
Location
This project was located in the Scott Valley in Siskiyou County. The project enhanced the work that was being completed as part of a 1,297 acre fuel reduction and shaded fuel break project located in the Patterson Creek drainage outside of Etna, California. The feedstock was predominantly Ponderosa Pine (Pinus ponderosa) at a low elevation site of 2,827 feet.
Project Implementation
The Scott River Watershed Council worked with multiple partners, each of whom was responsible for different aspects of the project. Falk Forestry was contracted to operate the carbonator for a two-week period. Jefferson Resource Company (JRC) oversaw the permitting, thinning, and feedstock preparation. Quartz Valley Indian Reservation (QVIR) shared their previous experience with biochar production, and Sonoma Ecology Center (SEC) contributed their research on biochar and assisted with the demonstration day.
The project fit into a larger hazardous fuel reduction and thinning project that was conducted on private land. In the spring and summer, wood was cut with a feller buncher and left to dry and cure over the summer months. The demonstration site was prepared by JRC, who delivered the feedstocks and skidded the log piles to the landing where the carbonator was set up.
Four personnel from Falk Forestry operated the carbonator for a total of 80 hours. One individual prepared the feedstock and loaded the carbonator, two individuals managed the machine, quenched the biochar, and assisted with loading, and the fourth individual operated the water tender and delivered the biochar. Each day, a small fire was lit inside the carbonator and once it was sufficiently hot, an excavator was used to break up the feedstock and load it into the carbonator. A water truck was staged nearby to provide additional water for quenching the biochar and to act as insurance in the unlikely event of an escaped ember causing an ignition outside the carbonator.
SRWC worked with SEC to amplify the benefits of their respective RFFC biochar demonstration projects (See SEC Demonstration Project ). Together, they established complementary performance metrics and developed a Community Outreach Day in which three different biochar processes were shared with the public: a conservation pile burn, Ring of Fire Kiln, and Tigercat 6050 carbonator. These methods were applicable to the participants, which included farmers and ranchers, timber company representatives, heavy equipment operators, loggers, Registered Professional Foresters, and small landowners. Representatives from local agencies also attended including CAL FIRE, Siskiyou Air Pollution Control District, and the USDA Natural Resources Conservation Service (NRCS).
A total of 216 cubic yards of biochar was delivered to five producers in the Scott Valley. SRWC worked with these agricultural producers to compost half of the biochar they received in order to conduct field trials through a NRCS Conservation Innovation Grant. After the demonstration project, SRWC worked with Wilson Biochar Associates to develop a biochar best practices guide (LINK) that includes information on how to compost biochar prior to soil application. This guide was distributed to the SRWC mailing list, attendees of the Community Outreach Day, and agricultural producers participating in the field trial.
Lessons Learned
Carbon Storage
As part of the shaded fuel break project, a total of 19.6 bone dry tons per acre were harvested from 19 acres of forest and staged for the biochar demonstration. The Tigercat 6050 carbonator reduced 373 bone dry tons of feedstock to 46.67 tons of biochar (about 13% of the bone dry tonnage). Lab tests indicated that the resulting biochar consisted of 50.8% carbon, meeting the International Biochar Initiative (IBI) standards for Class II biochar. The lab analysis also showed that the biochar did not contain exceptionally high levels of heavy metals. Based on the lab-determined bulk density carbon content, this project stored a total of 47,402.5 lbs of organic carbon as biochar, equivalent to 87 tons of CO2. It is expected that 70% of this carbon will remain in the soil for 100 years.
Figure 1. Laboratory analysis of the biochar produced by the Tigercat 6050 carbonator
Cost Effectiveness and Logistical Barriers
The Tigercat 6050 carbonator is a viable tool for forest managers, however external costs like transportation, run time, and seasonality must be considered when planning the purchase or operation of a carbonator. The largest cost component of the demonstration project was the transportation of the carbonator to and from the project site. The carbonator needs to be run for many hours in one area to amortize the transportation costs or more carbonators need to be available throughout the region to reduce transportation distance. With multiple hours of required startup and cool down time, the carbonator requires many consecutive hours of operation to be efficient. In addition, the carbonator can only be operated safely during the wet season in fire prone areas, limiting the period of utility. These issues are not insurmountable and should not be limiting factors to using this technology.
The availability of skilled workers to operate the carbonator can also be an economic barrier to mobile biochar production. Several of the employees working on this project had not operated a carbonator before. The conversion rate increased from 1.8 yards per hour to 5.15 yards per hour as the operators became more efficient over the course of the project. Proper training of operators is essential, especially when operating on short time scales. Additionally, training and utilizing local operators would reduce labor and housing costs.
For this 80-hour demonstration, the production cost was $1,635/hour. Costs could be reduced significantly if the carbonator was used for a longer period of time to amortize the transportation and set up costs and if local heavy equipment operators were trained to operate the carbonator. For example, if rental of the machines continued in the area for an additional 80-hour period with local labor the production rate would have been reduced to $666/hour. The benefits of potential carbon credits or selling the biochar could offset some of these costs. Working over longer periods of time and potentially across the region could also make the operation more financially feasible.
Air Quality Benefits
Pile burning was one management option for this site and is generally a cost-effective way to reduce biomass. However, piling and burning releases between 92% and 94% of the carbon in each slash pile to the atmosphere ( Finkral et. al 2012 ). This project significantly reduced smoke and carbon released into the airshed when compared to pile burning. Particulate matter was assessed visually by Air Quality Control Board staff on site. Particulate matter emissions were not visible on site during carbonator operation largely due to the air curtain, the high heat, and the efficiency of the carbonator. The pyrolysis process inside the carbonator produced very little smoke and contained the fire, thereby also reducing risk of escape.
Recommendations
Use a carbonator in tandem with large scale fuel reduction projects
The carbonator is best used in a forestry setting where there is a need to process large amounts of biomass efficiently. Its mobility and in-situ operation make it an attractive alternative to hauling chips or logs, and a safer option than open pile burning in terms of ignition risk and smoke production. For example, the carbonator could run behind a forest thinning project and convert 2-5 acres of biomass to biochar per day. Distributing the biochar back into the forest can also provide carbon sequestration benefits.
Increase cost effectiveness by sharing a carbonator throughout the region
Having a carbonator locally accessible to various landowners and projects would reduce the expense of moving the equipment, make its use more cost-effective, and increase its carbon sequestration benefits. The carbonator is safe to operate in the winter months in the Siskiyou region and could be put to use on the coast or in a fixed, protected location during the drier fire season. This coordination and collaboration would maximize run time of the equipment.
Train and employ local workers in biochar creation
Proper training of operators is essential, especially when operating on short time scales. Additionally, training and utilizing local operators would reduce labor and lodging costs for contractors coming from out of the area, as well as the CO2 emissions of this travel.
Engage landowners about the benefits of biochar
The Scott River Watershed Council will continue to explore the benefits of biochar and work with landowner-users through subsequent NRCS funding. Continued engagement and outreach efforts will help build demand for biochar and potential interest in using the carbonator for large scale biochar production. Currently, two NRCS conservation practices include the application and the creation of biochar. These practices will also help generate more demand for biochar over time and may increase the use of the small kilns or a carbonator on larger projects.
Related Solutions
More Information
Contact
To learn more about this project, please contact Alexis Robertson ( alexis@scottriver.org ). The project sponsor may be able to provide access to additional materials such as economic viability analyses and performance metrics.
