Chem321:Willow for sustainable energy
This is the 2013 paper by Stefan Sloma.
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In today’s ever changing world, the need for new sustainable resources has never been direly needed as it is now. With the price of oil on the rise and the abundance of fossil fuels dwindling the need for biofuels can’t emerge at any better time. The introduction of biofuels can create a new and young market that can be developed, refined, and promoted to give fossil fuels and other sources of combustible energy a run for their money, figuratively and metaphorically. Biofuels have to potential to create a sustainable energy source without depleting any stock that we are given to us by the planet. The key to this whole problem is finding some sort of biofuel where the usable energy is greater than the energy expended (Hill, 2011). If this can be plausible and there is a market structured for the biofuel then there is promise on the horizon. One type of biofuel that fits these criteria is the willow plant, or Salix.
With willow, the energy retrieved from this form of biofuel is much more potent than that of corn or gasoline. Shrub willow grows in all different climates, from the arctic to the tropics, they are found closer to the North Pole than any other woody plant (FAO, 2007). It all depends on the species being grown. Since willows and poplars (another type of biofuel) are so closely related they can be crossed with each other to create hybrids. These hybrids can be tailored to specific traits, once perfected sections can be cut off and planted just by sticking a cutting into the ground. By doing this you can create and infinite number willow clones (FAO, 2007). Once the willow is planted and harvested, only after three to four short years, the net energy ratio can be up to ten times that of corn and five times that of gasoline (Huang, 2013). Like all plants, willow is carbon neutral, leaving behind no carbon footprint after it has been harvested.
Biofuels are any type of fuel (ethanol, diesel, pellets, etc.) that is derived from living or dead biological matter, mostly plants or trees of certain sorts. Different types of plants can be used as biofuels, plants such as sugar cane, corn, willow, or peat can be converted into some sort of fuel. Some of these plants can be formed into bioethanol, sugars in things like sugar cane and corn can be fermented and the ethanol extracted and mixed with petrol (Hill, 2011). Biodiesel is made from oil seed crops, where glycerol is the wanted end product, the seed oil is converted to fatty acid methyl esters through transesterfication and produces glycerol (Hill, 2011). Another form of biofuel that isn’t a liquid or involves a chemical process is the use of wood or plant pellets that when burned produce clean energy and heat (Palsauskas et. al, 2013). Of all these processes I believe that the one most suitable for a sustainable environment is the formation of pellets.
Now there are many problems involving the process of biofuels and their growth. One problem is the amount of space needed to grow enough biofuel to offset even a fraction of the amount of fossil fuels we use. It’s said that to replace 5.75 per cent of the fossil fuels used globally that a land area equivalent to Austria, Germany, and the Czech Republic combined is needed solely for biofuel crops (Hill, 2011). In the case of willows as a biofuel, they don’t need to be grown like corn or sugar cane. As with corn and sugar cane which need acres of land, willows can be grown virtually anywhere and not take up high quality soil. Willow is able to grow on marginal land with little to no care (Ewy, 2013). In the past few years’ marginal land has been given some extra attention. These lands have been the focus for renewable energy instillations as opposed to valuable land to grow crops (JISEA, 2012). Willow can be planted, left with little to no care, and can grow on land that won’t take land that can be used for more important crops like food production. This would open up a new division of cash crops for farmers who have any spare land they can use to harvest willow.
Figure 1 Conservation Reserve Program (CRP) Lands as Proxy for Marginal Lands. Data collected by the EPA to show areas of the country that have available marginal land. This includes abandoned mines, deserts, and abandoned agricultural land (JISEA, 2012).
The Environmental impact of fertilizers and other sprays can be another problem when considering the growth of. For many crops such as cotton, rice or corn, there are several kilograms per hectare of potash, nitrogen and phosphate that are applied. The practice of applying nitrogen to crops has been linked to the release of greenhouse gases such as nitrous oxide. This leads to claims that biofuels actually contribute to global warming (Hill, 2011). With willow there is no need to worry about any releases of nitrous oxide into the atmosphere. In a study of willow growth conducted by Dr. Robert Ewy he found that willows don’t need any herbicides or pesticides to grow, that all they need is for the grass to be mowed around the area, even that doesn’t necessarily need to take place (Ewy, 2013). Without providing any sprays of chemicals the willows are allowed to grow naturally without the fear of any harmful chemicals seeping into the ground or into the air. Therefore without the release of these chemicals there should be a decrease in the amount of green house gases (GHG) being produced. Countries like Brazil have seen a reduction of GHG by 90 per cent with the use of bioethanol, while countries like the United States have only seen reductions from 10 to 30 per cent (Hill, 2011). With this information it’s plausible to say that willow production could show a decrease in the amount of GHG being produced. This doesn’t take into effect environmental costs of harvesting, production, transportation, etc.
Figure 2 Fertilizer Requirements for Main U.S. Crops. As you can see several of these crops need some sort of fertilizer while being grown. Willows don't need any of these fertilizers (Hill, 2011).
The third problem with biofuels is the relationship between usable energy and energy expended. The whole process of biofuels would be a waste if the energy received from the biofuels was less than the energy expended to retrieve it. To make the biofuels a prominent staple in sustainability the entire process, from harvesting to consumer distribution must stay local (in my opinion). It makes more sense to have biomass production closer to a processing plant rather than shipping it a long distance (Hill, 2011). With all biomass and biofuels you have to worry about transportation. In the case of willow the material wanted is the wood itself, the water and air trapped inside the wood makes transportation expensive. If a farmer could grow the willow and ship it to a processing plant that is closer rather than farther away they can cut back on money, time, and especially unwanted emissions. The processing plant can then sell to local companies, again cutting down on time, money and wastes, and then these companies sell the product locally. This will also keep all the money within the vicinity of these three major contributors. If you can find a place where willow or any biofuel can be grown and there is a local economy and society waiting for this biofuel then the logistics of biofuel processing all point towards production.
Now these three problems facing biofuel and their emergence onto the market are all things that have to be well thought out and planned. You wouldn’t want to plant a crop that has no immediate function in the present economy. That would just lead to more waste, you would want something that has a demand in the present and future to come. As I alluded to before there was the study done by Dr. Ewy about willow growth in the North Country of New York state. Dr. Ewy used a test plot for willow and determining which type of willow grew best in the climate conditions present in St. Lawrence County. He looked at 16 varieties of willow and wanted to see which one grew the best. He grew these 16 varieties on marginal land with poor soil conditions. This land also hasn’t been used for crops in many years so these plants weren’t taking any space away from food production. After the initial planting they would be allowed to grow for three years, during this time little to no care was given to the plants. Besides mowing the grasses around and within the crop, no outside herbicides or pesticides were given, an “all-natural” process of growth occurred. After the three years the plant then was harvested and measured for biomass. There is no need for replanting because the willow roots will be well established by then. This root system will allow the willows to grow back faster and larger than before. Once the biomass is measured for each of the 16 varieties it can be determined what singular variety can grow best on marginal land in the North Country. This variety can then be grown and exploited by breaking down the glucose in the plant and supplying a lot of gasoline (Ewy, 2013) or can be broken down into dry pellets for consumers who use wood burning stoves.
This process (sustainable energy and biofuels) has been studied very thoroughly in places that have low availability of fossil fuels, one place in particular is Lithuania. Lithuania is in a tight spot, here is little availability of fossil fuels present and they import most of their coal and fossil fuels from surrounding countries like Russia and Poland (Palsauskas, 2013). Because of their dependence on imported energy, Lithuania has approved a sector devoted to renewable energy and determining which biofuel produces the most energy. One experiment looked at the use of mixed biofuel for pellet production. They looked at sources such as peat, sawdust and peat, wood dust, sawdust, and sawdust and straw. In the end they determined that mixed biofuel pellets had the same, if not better properties than homologous materials (Palsauskas, 2013). Although this experiment didn’t test willow another experiment, also taken place in Lithuania, looked at 37 clones of Salix and wanted to compare dendromatic characteristics and dry biomass of the stems between the first and second crop rotations. In the end they were able to whittle the 37 down to 7 types of Salix. These 7 varieties showed the greatest turnover rate and are being studied further into how then can be used in the future for biofuel production as a short rotation crop (Smaliukas et. al, 2007).
These two experiments are just a glimpse into how willow and biofuels are being studied as one. As time goes by the need for an alternative fuel will keep growing. There’s no way we will be able to sustain the lifestyle that we are living right now if we don’t focus on better preparing ourselves and future generations with sustainable energy. We must begin to look at ways to exploit marginal land in the United States as viable real estate, not just for willow but also for solar, wind and other biofuel production. If we can harness this land and use it to our advantage by growing crops that don’t take up food production then we can establish economies based upon this biofuel and create a real competitor to fossil fuels. By doing this hopefully we can eliminate our dependency on oil and coal, decrease carbon dioxide emissions and move towards a sustainable and much environmentally friendly lifestyle.
Resources:
Ewy, R.G. 2013. Willow Video. Available from: http://www.youtube.com/watch?v=zrPNuOPflmQ
FAO. 2007. Growing Poplar and Willow Trees on Farms. National Poplar and Willow Users Group. Available from: http://www.fao.org/forestry/21644- 03ae5c141473930a1cf4b566f59b3255f.pdf
Hill, C., London, U.K. 2011. An Introduction to Sustainable Resource Use. 1st Ed. Earthscan Ltd., UK.
Huang, Y. 2013. Shrub Willow: Building a Better Biofuel. The Cornell Daily Sun. Available from: http://cornellsun.com/node/54709
JISEA. 2012. Renewable Energy Potential on Marginal Lands in the United States. Available from: http://www.jisea.org/pdfs/6a503012_poster.pdf
Palsauskas, M., Mauricas, T., Aleksandras Stulginskis University, Lithuania. 2013. Use of Mixed Biofuel for Pellet Production. Engineering for Rural Development. 369- 375.
Smaliukas, D., Noreika, R., Karalius, D., Vilnuis, Lithuania. 2007. Clonal selection of Salix L. taxa perspective for biofuel production, evaluation of their dendrometric characteristics and accumulation of biomass in short rotation plantations. Biologija. Vol. 53. 2: 59-62
