BioCycle November 2012, Vol. 53, No. 11, p. 53
“About three years.” That has been a common response to how long it will be before cellulosic biofuels are developed. I probably said it the first time eight years ago, but less in the last few years. Cellulosic biofuels, a subset of advanced biofuels, are transportation fuels made from cellulosic fiber. It is a real-life “Rumpelstiltskin” technology. When we get there, we will turn straw into gold.
One of the unknowns in the development of plant-based fuels is how production of bioenergy crops will compete for existing uses of crop production for livestock feed, human food and fiber. Crops grown for advanced biofuels, or purpose-grown energy crops, typically require a crop-specific processing plant for the production of a new energy crop to be profitable. These include crops like miscanthus, switchgrass, willow, and hybrid poplar, which don’t compete for existing agricultural markets but may displace land currently used for traditional commodities.
Developing and doing feasibility calculations on a frontier technology like advanced biofuels with few existing commercial facilities is challenging, especially as there is no available historical data. Currently I am involved in several levels of mathematical modeling for an advanced biofuels project in the Pacific Northwest. While some participants are developing the real, physical advanced biofuel infrastructure, others of us on the project team are growing crops and building biorefineries, balancing carbon and energy levels, and selling fuel mathematically with a series of sophisticated models.
The Advanced Hardwood Biofuels Northwest (AHB) is a USDA National Institute of Food and Agriculture (NIFA) funded project working to develop a Pacific Northwest biofuels industry. Coordinated by Rick Gustafson at the University of Washington in Seattle, it is focused on providing 100 percent renewable transportation fuels that are compatible with the existing fuel delivery infrastructure and derived from sustainably grown hybrid poplar trees. The project has a target of producing 400 million gallons/year of biofuel from 400,000 acres of hybrid poplar plantations around the Pacific Northwest. Private companies like GreenWood Resources, a hybrid poplar developer, and ZeaChem, a biofuel development company, are using existing and emerging technologies to physically produce the biofuels. Both have facilities in Boardman, Oregon, which is the first location for this commercial project.
Running The Numbers
About half a dozen different mathematical modeling groups are addressing multiple facets of the economic feasibility and environmental impacts of this project. I have been closely involved with two of them. One is the biomass supply model, known as the Bioenergy Crop Adoption Model (BCAM). The second is the biomass demand model, Geospatial Bioenergy Systems Model (GBSM). The GBSM is a biofuels conversion facility siting and production model. Both models were developed independently at the University of California, Davis (UC Davis), but in this current AHB project they fit together like a hand in a glove.
A few years ago, Stephen Kaffka, Director of the California Biomass Collaborative at UC Davis invited me to Davis to help develop the BCAM. One great characteristic of this tool is that it uses existing crop production data and economics to set a benchmark of cropping system profitability. Any improvements from introduction of a purpose-grown bioenergy crop have to be a marked improvement over the crops currently in production. Another great attribute is that BCAM is scalable from the crops on a specific farm, to a county, state or even a region. The most representative solutions come from having data available for smaller farm and county units. With great local data, the results are easily summed to provide state and regional results.
The BCAM-calculated poplar acres and price at which poplar production improves local profitability are then fed into the GBSM as feedstock inputs. The GBSM uses spatially-specific resources like transportation networks and feedstock locations to compute biomass conversion cost curves and determine optimal plant location and size.
Other models being utilized include a model of biofuel conversion plant operation economics and the lifecycle assessment (LCA). The LCA is the model that establishes the greenhouse gas and energy balances. Both of these undertakings are being done at the University of Washington.
An exciting dimension of this bioenergy technology frontier is that one year into a five-year calculation, we are still discovering technical coefficients required to do the math. For instance, on the crop production side, there are at least three different management strategies for growing poplars. Poplars have already been grown for hardwood lumber and also for paper and pulpwood production. They have not been grown for bioenergy, which uses different tree populations and harvesting technologies. If we build the data incorrectly it will give us answers that look right, but are not.
In the meantime, we are building BCAM cropping system datasets that include 60 traditionally grown field and forage crops over the five-state study area of Washington, Oregon, Northern California and Western Idaho and Montana. As we are able to refine the hybrid poplar energy crop data, we will tease the current crop production with new opportunities for bioenergy poplar.
The hope of bringing economic development to rural communities is one of the driving forces behind the excitement of biomass energy growth. These energy opportunities go beyond finding the next highest value residues and wastes. Opportunities also exist to produce new purpose-grown energy crops. And while the development of commercial advanced biofuels facilities is still largely experimental, we should have a commercial facility in about three years, well, maybe four.
Mark Jenner, PhD; World Agricultural Economic and Environmental Services (WAEES), California Biomass Collaborative, and Biomass Rules, LLC (www.biomassrules.com)