Air travel is a huge source of greenhouse gas emissions and a major consumer of fossil fuels. As a result Boeing and Airbus, as well as European airlines, have made major investments in developing aviation biofuel. In 2008 Boeing said that aviation biofuel would be a reality by 2011. Well, 2011 is here, but commercial aviation biofuel is still a ways off.
Jet fuel is essentially kerosene, and we know how to make kerosene from a variety of plants. There have been test flights using aviation biofuel, so we know planes can fly with fuel made from plants. At a recent conference, however, KLM said that the current price premium for aviation biofuel is approximately 5 times the cost of fossil fuel. In Europe, where a cap-and-trade program imposes a cost on using fossil fuel carbon, some premium for biofuel is commercially viable, but not that much premium. There is also a problem with growing plants to create jet fuel – taking land out of food production to produce jet fuel raises the cost of food and risks creating an unacceptable conflict for the world’s most vulnerable people. So what is needed is a source of plant carbon the production of which doesn’t compete for farm land needed to feed people. There is work going on to make biofuels from algae and grow crops on land that would not be farmed for food.
But you can also make kerosene from wood and forest waste, and indeed, the West has a lot of wood that needs to be removed from the forest before it is burned up in forest fires, after harvest of commercial forests in order to prepare the site for planting new trees, or to thin overstocked young stands so that they grow more valuable timber and provide better wildlife habitat. Is there a way to use that wood and forest waste as a feed stock for aviation biofuel? Researchers at Washington State University believe there may be, and the 2011 Washington Legislature took at least a baby step towards making that a reality.
SHB 1422, passed by the 2011 Washington Legislature and signed by Governor Gregoire, authorizes the Department of Natural Resources and the Department of Commerce to work with WSU and the University of Washington in their development of forest biomass aviation fuel. It directs DNR and the Department of Commerce to develop partnerships and pilot projects to demonstrate how to manage state trust lands to produce the feedstock for aviation biofuel while providing income to state trust beneficiaries – and oh, yes, to figure out how to do that in an economical and sustainable manner.
Those last two provisos are key. While there is a huge amount of potential biofuel feedstock in Washington’s forests, and removing that feedstock would potentially be very good for the forest, making it cost effective to use forest biomass for energy generation is an economic challenge. The problem is that the forest biomass is spread diffusely across the forest, and concentrating it and then hauling it to a central processing location (refinery) can take a very large share of the energy the biomass contains. Indeed the reason fossil fuels are so attractive economically is that they are the product of a few billion years of the earth concentrating dead plants, turning them into very concentrated energy sources. Electricity co-generation has become economically viable at mills turning logs into structural lumber or other solid wood products, but co-generation works there because the scrap that is burned to create electricity had to be hauled from the woods in order to make the 2 X 4s and plywood that are the central purpose of the mill, and would have to be disposed of if it weren’t burned to create electricity. The forest biomass that is a potential feedstock for aviation biofuel, by contrast, doesn’t have a high-value solid wood product associated with it. The potential biofuel feedstock is slash left after a commercial harvest, trees removed in pre-commercial thinning of overstocked young stands, and massive areas of dead or dying trees that have been subject to mountain pine beetle attacks across the inland West. That material needs to be removed from the forest so that the forest can be managed for better commercial forest production and wildlife attributes. If left in the woods, it will either rot, releasing methane gas, or burn, releasing all its carbon as carbon dioxide. But that biomass currently stays in the forest precisely because there is no solid wood product that can be made of it which would justify hauling it to a mill.
The issue of sustainability is also serious. As with any form of “agriculture,” removing all the biomass from one crop of trees, and then another, and then another, could quickly deplete forest soils of essential nutrients. We don’t know, and probably cannot know for a while, exactly what the consequences for sustainability are on the mass removal of forest biomass from the forest. We do know that leaving all the biomass in place in overstocked and dead forest areas has negative consequences – so there is no “free” choice here. Today ash from co-generation facilities is typically spread back on the forest floor, to return minerals to the soil. Whether that is an adequate response or will have adverse consequences is something that time and research will need to tell us.
One of the solutions to these problems that researchers are reportedly working on is to create a small, mobile processing unit that could do the initial processing of biomass into a liquor in the woods. The liquor would then be hauled to a refinery for further refining. The processed liquor would be more concentrated energy than raw biomass, and hauling a tank car of liquor to a refinery would potentially be more economical than hauling unprocessed biomass. At the same time, the waste from that initial processing could be spread back on the forest floor, without having to be hauled from a central refinery or processing area. If the mobile processing unit was truly mobile, when one area was cleared of unwanted forest biomass, the processing unit could be moved to a new location, so that raw biomass never needed to be hauled any significant distance. If such a mobile processing unit can be developed, it may provide the breakthrough to bring the cost of aviation biofuel from forest biomass down to commercially viable levels.
SHB 1422 requires DNR to report to the Governor and the Legislature by December 1, 2011 and again on December 1, 2012 on the progress being made, and the implications for forest management. It also provides that if a research university or foundation derives income from commercialization of patents, copyrights or proprietary processes or licenses that derive from the partnership with DNR, the state must receive income in proportion to the state resources used to develop the commercial processes. Whether that will lead to aviation biofuel from forest biomass is yet to be known – but at least SHB 1422 takes a baby step in that direction.