The changing markets for almond byproducts have led the Almond Board of California (ABC) to step up its research into alternatives to managing orchard removal biomass, as well as hulls and shells. The loss of cogeneration facilities is making it harder, and more expensive, to find homes for the wood materials. At the same time, the value of hulls has significantly declined as the demands from the California dairy industry are decreasing while almond hull production is increasing.
In addition to investing in research, ABC is working closely with the Almond Alliance of California (AAC), formerly the Almond Hullers and Processors Association, to provide relevant data to assist AAC in its efforts as part of a broad coalition seeking state legislative and regulatory solutions to the state’s management of wood materials.
UC Davis and USDA-ARS have developed some value-added chemistry processes for almond byproducts, such as hulls, but these need to be field-tested.
Orchard Removal
Traditionally almond orchard removals have been a large source of materials for cogeneration plants. But due to changes in the electricity market, electricity providers are choosing not to re-sign contracts with cogeneration plants. As a result, there have been several closings of cogeneration plants in the San Joaquin Valley.
With the industry anticipating a significant increase in orchard removals over the next several years based on the natural life cycle of the trees and the continuing impact of the drought, the Almond Board is conducting research on several fronts into alternative uses for almond tree removal biomass.
Whole Orchard Grinding Research
One alternative for dealing with tree biomass upon orchard removal is the process of grinding up entire almond trees and incorporating the tree biomass into the soil. This leads to the question of how this additional organic matter affects the soil, and more importantly, how it might impact the health of a subsequent almond orchard planted in these soils.
An orchard recycling trial project conducted over six years at UC Kearney Ag Center has shown some promising results, according to Dr. Gabriele Ludwig, the Almond Board’s Director of Sustainability and Environmental Affairs. “The results look promising in that the young trees could handle it and after three years we saw benefits to the soil.” San Joaquin County UC Cooperative Extension farm advisor Dr. Brent Holtz has led this research.
The Board is now funding additional trials to see if the results can be replicated in different types of soils, to learn how best to grind up the trees and incorporate the material, and to ensure that the recycling doesn’t spread diseases.
Bioenergy and Value-added Alternatives
Almond Board-funded research is delving into the area of bioenergy, also known as bio-economy, to maximize potential value of almond biomass as bioenergy feedstock. This approach utilizes newer, more efficient thermal, biochemical or biological conversion and/or extraction technologies to produce biogas, liquid fuels, biochar, bioethanol, liquid fertilizers, value-added materials and chemicals from almond biomass. Biogas and biofuels are clean energy feedstock. Biochar can be used as a soil amendment. The modified materials can be used as additives to improve properties of plastic containers such as garbage cans, flower pots and rubber tires, and the chemicals may be used to make fiberic materials and food/pharmaceutical additives.
These processes might also be useful for alternative or higher value uses of shells and hulls. Almond hulls are a good source of animal feed and typically have a much higher economic value than shells. However, with the price of corn coming down and the California dairy industry struggling economically, the value of almonds hulls has decreased significantly.
Ludwig notes that UC Davis and USDA-ARS have developed some value-added chemistry processes for almond byproducts that need to be field-tested. “A number of private companies have contacted the Almond Board about using almond byproducts, including wood, hulls and shells, for some of these processes for facilities they plan to build or to have shipped outside of California,” she explained.
Air Quality Implications
A lot of questions need to be answered about the new bio-economy processes. “We don’t know whether they can meet the ‘new source review’ requirements under the Clean Air Act in California for NOx or PM2.5,” noted Ludwig. “We don’t know how their carbon/criteria air pollutant footprint compares to the current cogeneration systems, and we don’t know how much investment it will take.” What all of these research initiatives need is some more time. “With all of these possible approaches we need to figure out how to make them usable under a wide range of circumstances and sort out any possible regulatory issues,” Ludwig said, "and this will take time."
