Chapter 6: Biofuel Feedstocks in Oregon
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| Imported Feedstocks |
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| The biofuels feedstocks with the highest yields grow primarily in the tropics. Oil palm, sugarcane and other tropical plants can produce much higher yields per acre than temperate plants like corn or canola. As a result of this high yield, the net energy of biofuels derived from tropical feedstocks is higher and the requirements for land are generally lower. Higher yields also mean lower prices, which makes importing feedstocks a tempting proposition. However, there are significant sustainability concerns associated with production of these feedstocks. Palm oil and tropical soybean production in particular are leading drivers of deforestation in the rain forests of Indonesia and Brazil, respectively, which together contain much of Earth’s biodiversity. While there is substantial fallow land available in these countries to increase production, poor enforcement of existing regulations and unclear land tenure often result in the clearing of large tracts of virgin forest, which results in biodiversity loss and substantial greenhouse gas emissions. Other issues include poor labor conditions on plantations and the loss of land rights of indigenous groups. In addition to these important environmental and social concerns, importing feedstocks from abroad conflicts with Oregon’s interest in developing a truly local biofuels industry. Thus the use of imported feedstocks should be strongly discouraged. As part of the renewable fuel standard passed by the Oregon Legislature in 2007, the Oregon Environmental Council worked to ensure the standard cannot be triggered by biodiesel produced from imported palm oil. If feedstocks are imported, they should come from third-party certified sustainable producers with a clear chain-of-custody. And any policy initiatives in Oregon to promote low-carbon fuels should take into account greenhouse gas impacts from imported feedstocks, particularly those caused by the clearing of forests and native habitats. |
6.1 Biodiesel feedstocks in Oregon
6.1.1 Soybeans
Soybean biodiesel, and biodiesel more generally, is regarded to be relatively energy-efficient with a net energy balance of around 3.2 (as opposed to .85 for diesel).61 While between 75-90% of current biodiesel production comes from soybeans,62 there are a range of reasons why they are not an appropriate feedstock for Oregon. Most obviously, soybeans are not well suited for growth in the Pacific Northwest. There are also several other problems with soybeans. Soybeans only yield 20% oil, producing approximately 53 gallons of oil per acre. Because soybeans cannot be easily crushed, the oil is usually extracted using a chemical solvent (usually hexane), which has a range of negative environmental impacts, including the release of hydrocarbons.63 The low oil yield per acre and difficulty of extraction make soybeans far from optimal as a biodiesel crop. US soybean production primarily occurs as part of a rotation with corn, and is very intensive in its use of chemical inputs.
Greenhouse gas impacts: A 1998 study by USDA and USDOE estimated that soy biodiesel provided a 78% improvement in CO2 over fossil diesel.64 This study looked only at CO2 and not at other GHGs, like N2O or methane that are produced during soybean production or refining. As a result the actual GHG benefit of soy biodiesel is most likely lower than this. Other studies that look at all GHGs suggest a low end of 40% improvement.65 If land-use change is fully accounted for, soy biodiesel fairs even worse. In Delucchi’s recently updated Lifecycle Emissions Methodology,66 which includes estimates for emissions from converting pasture, CRP and other lands to soybean production, soy biodiesel comes in at best at 20% better than gasoline and can easily be worse, although he acknowledges a great deal of uncertainty in calculating the impact of the nitrogen inputs for soy biodiesel. This is because of the very low oil yield per acre, which will require vastly more land to produce the same amount of biodiesel than other feedstocks, with an inevitable negative impact on global warming.
6.1.2 Brassica oilseeds
The most promising conventional oilseed crops for Oregon are the high-yielding oilseeds in the Brassica genus: rapeseed, canola (low-acid rapeseed), camelina, mustard and others.I While soybeans are the main feedstock for biodiesel in the US, the majority of biodiesel in the world is produced from rapeseed, primarily by European producers.
Rapeseed or canolaJ produces a substantially higher oil yield than soybeans, producing about 40% oil by weight and generating over 100 gallons per acre compared to the 57 gallons per acre US average for soybeans.66 Another important advantage is that canola oil can be produced through mechanical crushers and expellers and doesn’t require solvent extraction, which allows for less toxic and more sustainable production. In Oregon, canola can be grown in rotation with wheat and other crops which have substantial biofuel potential (see below), opening possibilities for integrated facilities. An Oregon State University study of the net energy gain from Oregon canola biodiesel suggests a 69% net energy contribution.68
Canola does have some disadvantages, however. It cross-pollinates with other members of the Brassica genus, which has led many farmers of other Brassica crops to oppose it being planted near their farms. It has relatively high nitrogen requirements,69 which can lead to significant chemical fertilizer inputs which in turn can have negative implications for water quality and GHG balance, and is not particularly drought-tolerant, meaning that it will require irrigation in many areas of Oregon. However, canola is currently successfully grown using agricultural practices certified by such third-party certifiers as Oregon Tilth and the Food Alliance.
While canola has been bred commercially for years and its oil yield has been optimized, other related Brassica oilseeds’ potential has not been as well developed. In particular, camelina, which has been cultivated for thousands of years in Europe, has a number of properties that may make it superior to canola as a biodiesel feedstock: it is drought-tolerant and requires fewer fertilizer and nitrogen inputs.70
Mustard seed is another interesting option. Yellow mustard (sinapsis alba) has been identified as a promising option for Oregon; although the seeds are only 27% oil by weight, yellow mustard may still be able to produce up to 100 gallons per acre.71 Yellow mustard is drought-tolerant, can be grown in rotation with wheat and other crops, and the oil is not used for cooking, which helps make it more competitive as a biodiesel feedstock. The meal is high in glucosinolates, which makes it unusable as an animal feed, but which gives it properties as an organic pesticide.72 The National Renewable Energy Laboratory and the University of Idaho have been working on developing higher glucosinolate mustard hybrids that can produce both a high-value organic pesticide, which would help reduce the water quality and environmental impacts of crop production, and a biodiesel feedstock.73
While further research and breeding for these crops and others is necessary, it is very likely that the best approach to oilseeds in Oregon will be to develop a range of oilseed crops optimized to different conditions and to encourage the development of biodiesel production facilities that can be flexible in terms of feedstock.
Greenhouse gas impacts: As with soybean biodiesel, the real impact of canola biodiesel depends on the details of the cropping system and the efficient use of co-products. However, there are some reasons to believe that the GHG balance of canola or rapeseed methyl ester biodiesel (RME) will be better than soybeans. The most important is the nearly double yield of biodiesel per acre from RME, which substantially reduces the environmental footprint. Unlike soybeans, canola can’t be grown in the tropics, so there is less chance for a direct displacement of production to high-biodiversity areas.
However, the often higher inputs of nitrogen required for canola mean that some of this advantage is lost. A recent study even suggested that Swiss RME had a worse GHG balance than US soy biodiesel.74 But a survey of other studies of rapeseed biodiesel produced in Europe has suggested a consensus range of 50-60% fewer GHGs than petroleum diesel although there is still substantial uncertainty about the impact of N2O emissions.75
A study by Oregon State University professors suggested that canola biodiesel produced in Oregon would reduce GHG emissions by 40.5% compared to petroleum diesel. If a high-yield, low-nitrogen camelina or other crop can be developed for Oregon, it would almost certainly have a substantial GHG improvement over current canola varieties.
Oregon potential: There are only about 3,000 acres of canola being grown in Oregon and almost none of the other types of oilseeds. The best possibilities for growing canola in Oregon are in the Columbia Basin, the northeast region, the central region, and particularly the Willamette Valley. However, because specialty vegetable seed growers are worried about cross-pollination, the Oregon Department of Agriculture has instituted a ban on growing Brassica crops as feedstock for biofuels in the Willamette Valley, three central Oregon counties, a part of northeastern Oregon, and a little strip of Malheur County that borders a canola-restricted area in Idaho. Other crops, like yellow mustard, which don’t cross-pollinate with Brassica crop relatives under field conditions,76 might offer one solution to this problem.
In terms of technical potential, a 2004 OSU Extension study estimates that around 300,000 acres might be available yearly for canola in central and eastern Oregon, with another 200,000 in the Willamette Valley.77 Assuming 100 gallons per acre, the upper limit of biodiesel production would be around 50 million gallons, although the near-term potential is likely to be half that.78 Increases in yields and the introduction of new drought-resistant crops that could grow in arid areas like the Klamath region could increase this potential substantially. At current diesel consumption levels, Oregon needs 40 million gallons of biodiesel for a statewide B5 blend, so this could be a feasible mid-term goal for the state.
6.1.3 Waste oils and fats
The most environmentally friendly and energy-efficient possibility for biodiesel production is the use of waste vegetable oil and animal fats. Even after oil has been used for cooking or deep frying, it can be cleaned and converted into biodiesel. The biodiesel itself has properties that are similar to that produced from virgin oil feedstocks. Another source of biodiesel feedstock is animal fat and tallow from slaughterhouses and other processing facilities.
Greenhouse gas impacts: Because biodiesel from waste products displaces fossil fuels without requiring any dedicated agriculture production it provides serious advantages in GHG balance and does not have the environmental impacts associated with agricultural production. One study stated that waste vegetable oil biodiesel in Europe produced a life-cycle assessment GHG benefit of over 70% compared to petroleum diesel.79 There are no studies of the GHG balance of biodiesel produced from animal fats. Although animal fats are essentially a waste product, methane from livestock and manure is a major source of GHGs; if this were factored in, biofuels from animal fats might result in a less favorable GHG balance.
Oregon potential: One company in Oregon, SeQuential Biofuels, already produces biodiesel from waste vegetable oil, although it plans to expand production at this plant with oilseed feedstocks. Although exact data is unavailable, SeQuential Biofuels estimates that each Oregonian is responsible for 1 gallon of waste vegetable oil a year. Based on this rough estimate there may be around 3.5 million gallons of waste vegetable oil produced in Oregon per year,80 although how much of this it is economical to actually use is an open question.
| Policy Recommendations - The Glycerin Challenge: |
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| Biodiesel production produces 10% glycerin (or glycerol) as a byproduct. While glycerin has a range of uses in soap, cosmetics, pharmaceuticals, and other products, the huge amounts of glycerin that will be produced as biodiesel production ramps up has the potential to create a glut in current markets but is also a great opportunity. Because glycerin sales are an important component of the profitability of biodiesel production, not to mention a key component in the net energy balance, finding uses for all of the glycerin will be an important part of ensuring the long-term viability of the industry. Uses could include high value chemicals like propylene glycol, the production of biogas or other uses that are appropriate to the local circumstances. Funding research into what the most economic and environmentally beneficial use of glycerin might be in Oregon, will help both support local biodiesel producers and could also create other industries in the state. |
6.2 First-Generation Ethanol Feedstocks in Oregon
6.2.1 Corn
The first ethanol plants being constructed in Oregon will use corn, mostly imported from the Midwest. Corn yields around 300-400 gallons of fuel per acre,81 however corn is also a notoriously high-input crop, usually using large quantities of nitrogen, pesticides and water. Midwestern corn production is associated with a host of environmental problems, including eutrophication and the “dead zone” in the Gulf of Mexico, falling water tables and reduced water quality, soil erosion and other problems.
Corn products are also tightly woven into nearly every aspect of our food production system, and as the price of a bushel of corn has gone from around $2 to over $4 dollars in the last year, concerns over the impact on food prices have been raised.
Because of the energy intensity of corn production, USDOE estimates an average net energy gain of around 1.67, with .61 of that coming from the co-product credits (see the section on net energy balance [3.1] above).82 As a result, while corn ethanol does displace petroleum, it provides relatively little reduction in overall fossil fuel use. Corn ethanol provides comparatively lower GHG benefits than other biofuels, with the Argonne National Laboratories suggesting an 18-29% improvement in GHG emissions over gasoline83 from natural-gas fired plants. If the processing is done using coal, it can actually be no better than gasoline from a global warming perspective.84
| Policy Recommendations - Corn Ethanol: |
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| Considering the high environmental cost of industrial corn production, it is no surprise that corn ethanol is fairly controversial. Still, it is possible to do corn ethanol better. Improved agricultural practices and processing plant designs can substantially reduce the environmental impact of corn ethanol and improve the GHG and energy balance. Since it seems inevitable that Midwest corn will be imported into Oregon for ethanol, Oregon should devise incentives to encourage the use of these best practices. Because corn is not an appropriate ethanol feedstock for Oregon, the Oregon Environmental Council helped ensure that the state’s new biofuels feedstock tax credits are not available for corn production. |
6.2.2 Wheat
Oregon grows substantially more wheat than corn; in fact 2007 production of winter wheat is estimated at 40.7 million bushels from 740,000 acres. Wheat is also a viable feedstock for first-generation ethanol and can be produced in the same facilities that process corn. Ethanol yields for wheat are lower, often under 300 gallons per acre, and the net energy and GHG balances are in the same range as corn.85
When broader potential bioenergy systems are considered, wheat may have an important place in Oregon. This is because wheat straw is one of the most abundant cellulosic feedstocks in the state, and fully utilizing this resource could also change the environmental feasibility of first-generation wheat ethanol. For example, if wheat straw were used to produce heat and power for a first-generation ethanol plant, the GHG gas benefits could easily be doubled (a UK study suggested a 48% reduction) and the fossil energy inputs nearly eliminated.86 These plants could then be modified to generate an increasing portion of cellulosic ethanol as well, a technique that is already being implemented in other states.K
Yields from corn ethanol plants have been improving dramatically, and it is certainly possible that production could be optimized for wheat to make it competitive with corn. While the large-scale use of wheat as a feedstock would clearly not be sustainable and would compete with food, some use of wheat as a bridge to more advanced technologies should not be discounted.
Oregon potential: If Oregon’s entire 740,000 acres of wheat were devoted to ethanol production, it could produce over 200 million gallons per year, although this would not be feasible or advisable. Oregon has a well-deserved reputation for high-quality wheat for which millers are willing to pay premium prices.86
6.2.3 Sugar beets
While current US sugar policy means that producing ethanol from sugar beets is unlikely to be economically viable,88 sugar beets and molasses are still a potential ethanol feedstock in Oregon and one that has some environmental advantages over grain ethanol. The technology is well established, as sugar beets are currently the main feedstock for ethanol in Europe. Because starch feedstocks like corn and wheat must first be converted into sugar and then fermented into ethanol, using sugar crops saves a step and a corresponding amount of energy. Yields are correspondingly higher, and West Coast sugar beet producers, including Oregon, have the highest average yield in the country. In 2004, the Far West region (California, Idaho, Oregon and Washington) had average yields per acre ranging from 28-31 tons per acre,89 which at an average rate of 24.8 gallons per ton would produce between 694-776 gallons per acre, more than double the average yields for corn ethanol.
Considering the high value of refined sugar, another possibility for the production of ethanol would be the use of molasses, a byproduct of producing refined sugar. Sugar beet molasses is usually desugared90 to extract maximum value and sold as animal feed, but a USDA study suggests that it may be economical to convert molasses to ethanol. Molasses ethanol has been developed as a successful industry in other countries, notably India, where high demand for sugar makes it uneconomical to convert sugarcane directly to ethanol.91 Existing processing facilities could be converted to ethanol production, either from beet juice or molasses, which would also lower the environmental footprint.
Greenhouse gas impacts: A study of sugar beet ethanol in Switzerland stated that it produced well over a 50% improvement in life-cycle assessment of GHG emissions. Since molasses ethanol is a byproduct of sugar production and doesn’t require any dedicated land, it should have even greater benefits than this.
Oregon potential: Oregon produced 360,000 tons of sugar beets in 2006, which would amount to nearly 9 million gallons of ethanol. It is likely that only a small fraction of this will be economical to convert to ethanol, however.
6.2.4 Potatoes
As a high-starch plant, potatoes are suitable for ethanol production. In particular, a substantial portion of the potato crop is unsuitable for commercial use, with waste potatoes accounting for 5-20% of the crop. Potato peels and other waste products from processing potatoes are also a viable source of ethanol production. Ensuring that ethanol plants that handle other feedstocks like wheat or corn can also process potato waste may be more viable than producing dedicated potato-ethanol plants.
Greenhouse gas impacts: Using potatoes as a primary feedstock is not ideal due to their relatively low yield compared to other feedstocks. A study of GHG balance of potatoes in Switzerland suggested that they were slightly worse than US corn, although the applicability of this study to Oregon is unclear.92 The use of waste potatoes, potato peels and other byproducts would be a likely improvement over corn and wheat ethanol.
Oregon potential: In 2005 Oregon produced over 22 million hundredweight (cwt) of potatoes93 and should have substantial potential for potato ethanol. More research into how much waste potato feedstock is really available in Oregon and the economics of transporting it to possible plant sites needs to be done. This might be a good project for Oregon BEST, the Bio-Economy and Sustainable Technologies Research Center that is being developed in the Oregon University System.
6.2.5 Whey and other agricultural byproducts
Whey, a relatively low-value byproduct of cheese production, is another viable and environmentally sound ethanol feedstock for Oregon. Whey can be readily fermented to ethanol with little pre-processing or energy inputs. There are already several whey-to-ethanol plants in the US, although most are relatively small scale. It is not clear what yields are possible from optimized production, but interviews with whey-to-ethanol plant owners have suggested that 100 gallons of whey can produce 10 gallons of ethanol.94
As an easily fermentable byproduct, at least one study ranked whey ethanol as having the lowest net GHG balance and lowest overall environmental impact of any ethanol feedstock, including cellulosic ethanol.95 While the quantities of whey ethanol that are economical to produce in Oregon are unclear, a gallon of whey ethanol is clearly more beneficial from an environmental perspective than most other types of biofuels.
These findings are probably generally applicable to a range of agricultural byproducts and waste products. Incentives to encourage farmers and entrepreneurs to fully utilize byproducts of agricultural production have the potential to reap substantial dividends in reducing GHGs and improving the environment more generally.
While production plants from these sources are likely to be relatively small-scale, this can be as much an advantage as a disadvantage, as discussed under the section on social sustainability. Smaller, locally owned plants can help improve rural incomes, while utilizing waste products that would otherwise need disposal and providing substitutes for fossil fuels.
Oregon potential: Considering the incredible diversity of agricultural products made in Oregon there are likely to be a range of other waste streams that can be viably turned into ethanol or otherwise used for energy. Non-merchantable fruit or fruit processing waste is one likely possibility.
| Policy Recommendations - Whey and Other Agricultural Byproducts: |
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| Of all types of biofuels, those derived from waste products are all-around winners. An Oregon-wide survey of agricultural waste streams, the economics of transportation and the necessary conversion technologies would be an important first step to identifying where the most promising areas for investment are. The state should also create incentives, such as tax breaks, and offer loan guarantees for smaller-scale plants that can take advantage of locally available, no-value waste products that aren’t economical to transport to larger plant sites. |
6.3 Second-Generation Biofuel Feedstocks in Oregon
All of the feedstocks discussed to this point for both biodiesel and ethanol have one thing in common: they are used as food or feed. While the impact of conventional biofuel production on food security worldwide is hotly debated, it is clear that the ideal solution is to use biomass that does not compete with food production, or biomass that can be produced along with food. Oregon has far more potential to produce biofuels from cellulosic sources than from first-generation feedstocks. In either case, feedstocks must be produced using sustainable practices.
A few caveats are necessary when considering cellulosic feedstocks. While most of the media attention and research have focused on producing ethanol from cellulosic feedstocks, it is not clear that will in fact be the case. Several companies, notably BP and DuPont, are working to commercialize cellulosic biobutanol, which has a much higher energy content than ethanol. Biomass gasification platforms, so-called biomass-to-liquids, can produce a range of liquid fuels, including ethanol, biobutanol, hydrogenation-derived renewable diesel and more. Producing fuels with a higher energy content or better properties than ethanol could increase the effective yield from cellulosic crops without increasing production. Considering this uncertainty, from a policy perspective it is important to develop incentives that are as neutral as possible with regard to technology. All of the estimates of ethanol yields in this section are only best estimates from existing technology.
Perhaps the greatest obstacle to the utilization of cellulosic biomass is the problem of transportation. Cellulose is bulky and heavy and difficult both to collect and transport. Unless some sort of on-site pre-processing can be done,L it is generally estimated that sufficient biomass needs to be within a 50-mile radius of a production facility for it to be economic. Besides limiting what biomass can be economically used, it also suggests a relatively heavy environmental footprint for a cellulosic biofuel plant, with streams of trucks coming from surrounding areas. With agricultural residues, this would also have to happen at specific times of the year, raising concerns about air and water quality. According to one article, a million tons of corn stubble could take 67,000 semi-trailer loads, which work out to a truckload every eight minutes.96 Still, if these issues can be overcome, Oregon has a range of possible cellulosic feedstocks that could be developed for biofuels.
6.3.1 Dedicated energy crops
Similar to the way that food crops have been developed over millennia to maximize their ability to produce high-quality food, there is growing interest in developing crops that are designed specifically for energy. The two broad categories of plants that have been the focus of these efforts are tall grasses, such switchgrass and what are known as short-rotation woody crops (SRWCs), essentially fast growing trees that can be harvested every five to six years. The advantage of dedicated energy crops is the possibility of regularly harvested, consistent feedstocks whose properties can be tailored through selective breeding to maximize their energy potential. The “Billion Ton Study,” a USDA-USDOE project that determined the feasibility of a billion tons of biomass being generated yearly in the US by 2030, suggested that dedicated energy crops were essential if this level of biomass production was to be sustainably reached.97 The study found over 1.3 billion dry tons per year of biomass potential – enough to produce biofuels to meet more than one-third of the current demand for transportation fuels in the US.
From an environmental perspective, dedicated energy crops have several distinct advantages over traditional food crops. First, all of the dedicated energy crops being considered are perennials, meaning they do not have to be replanted. This eliminates the need for tilling and allows deep networks of roots and below-ground biomass to develop, which helps rebuild fertility and sequester carbon in soils. Generally speaking, these crops require far fewer chemical inputs once established and, because they are not harvested every year, provide better habitat for wildlife.
Some promising research has examined the use of mixes of native grasses for biomass production.98 These mixes are the closest to natural ecosystems and would likely bring the greatest environmental benefits. Ideally, these could be grown on marginal and unproductive lands. Whether enough biomass can be produced to make these economically sustainable is still an open question, however.
Hybrid poplar
Switchgrass, which is considered one of the most promising native tall-grass species for energy production, does not grow well in Oregon, although this may change as new commercial breeds are developed. Of the dedicated energy crops that are currently being talked about, hybrid poplar is already being grown on 34,000 acres in Oregon99 and there is a growing body of research on its environmental properties.
It is important to understand that while poplars are “trees,” hybrid poplar plantations and other short-rotation woody crops (SRWCs) are not “forests.” They are highly managed compared to traditional plantation forests. For example, the area between the trees is often tilled for the first few years to eliminate weeds, which impacts biodiversity. And while SRWCs provide habitat for some kinds of wildlife, they are not comparable to natural forests.100 Hybrid poplars require very little pesticide application, and herbicides are primarily used during the first few years of stand establishment.
The “hybrid poplar” trees grown in Oregon are actually a cross between Eastern cottonwood and black cottonwood and can be harvested six to eight years after planting. With current breeds about 10 tons per acre could be grown annually, which, at a conversion rate of 65-70 gallons per ton, could mean a yield of 700 gallons per acre of ethanol. Purdue University researchers have suggested that lower-lignin varieties could produce up to 1,000 gallons per acre.101 Estimates of the net energy balance for poplar ethanol range from 84%102 to over a 100%, although this is likely dependent on the use of the lignin byproduct for generating power.
Greenhouse gas impacts: With deeper root systems, no yearly tillage, and only minimal applications of fertilizer,M hybrid poplar have the potential to be carbon-negative, which means they remove more carbon from the atmosphere than they release to the atmosphere. A recent evaluation by USDA scientists found that hybrid poplar used for ethanol reduced net GHG emissions by -165% in the short term.103 Once soil carbon levels reach equilibrium and soils are no longer absorbing carbon, hybrid poplar bioenergy systems still showed an impressive 117% improvement over gasoline. Net GHG emissions were better in both the short-term and long-term than for any other crops, including switchgrass and reed canarygrass.
These benefits would be realized when existing agricultural land is moved into hybrid poplars, but any clearing of existing forest land, including longer-rotation plantations, would release large quantities of GHGs immediately and require decades of production to break even. As a bioenergy crop, poplars are superior on all environmental criteria to any of the first-generation crops discussed above and can be grown on much of the same lands.
Oregon potential: Current hybrid poplar plantations were established primarily to supply pulp and paper mills, but companies have been shifting to longer harvest rotations to grow timber.104 With these longer rotations and the high value of most of the biomass, current plantations might produce 23,800-51,000 bone dry tons (BDT) per year in residues that would be available for biofuel production.105 This suggests that under the most optimistic assessment current plantations might produce around 3.5 million gallons of ethanol. It is unclear how much space in Oregon might be available for dedicated hybrid poplar breeds, and this would likely be determined by the economics. In Eastern Oregon hybrid poplars require irrigation (usually drip irrigation), and since the plantations would need to be close to the processing plant, which will also require substantial amounts of water, this could limit their expansion.
| Policy Recommendations - Short-Rotation Woody Crops: |
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| In the long-run it would make far more sense to convert wheat or corn acreage that is being used for biofuel production to hybrid poplars or other short-rotation woody crops. However, grain and food crops are generally of higher economic value. Ironically, as expanded first-generation biofuel use pushes prices for grains higher, it makes cellulosic crops even less economically attractive.106 Providing farmers with a payment for improving the net-GHG flux of their lands within a cap and trade system would be one way to encourage short-rotation woody crops. Another possibility would be the creation of a low-carbon fuel standard, where the higher GHG reduction value of biofuels from hybrid poplar would create stronger markets for cellulosic biofuels and allow producers to pay farmers more for biomass. |
6.3.2 Agricultural residues
While dedicated energy crops hold the greatest long-term potential for fossil fuel and GHG reductions, the short-term potential is more limited and the economics uncertain. As noted above, the use of agricultural waste products, like whey or waste vegetable oil, produces the greatest net benefits without competing for existing land. Agricultural residues, composed of the inedible parts of food crops such as corn stover and wheat straw, represent a vast potential reserve of biomass that doesn’t compete with food production.
However, agricultural residues are far from being “waste” products; they are an integral part of a healthy agricultural system. Leaving residues on the field helps protect against soil erosion, maintains soil fertility and nutrients, retains soil moisture, and improves carbon sequestration.107 As a result, only a fraction of the residues produced are actually available for use as bioenergy feedstocks. Determining a sustainable rate of residue removal is far from a straightforward exercise as it depends on the level of tilling, soil and climate type, and other variables. USDA is currently engaged in a long-term study to determine what sustainable removal rates are.
Greenhouse gas impacts: As agricultural residues don’t require dedicated use of land or separate inputs, the GHG balance is expected to be more favorable than that of first-generation biofuels, but less than that of dedicated energy crops, because there is no sequestration of carbon in soils or perennial biomass. Estimates range between roughly 50-90% reduction in GHG emissions, although just as with corn or wheat ethanol, agricultural practices will be the most important factor. It is possible that excessive removal of residues may also have a negative impact on GHG balance by leading to more soil erosion and loss of carbon, and this is an area that needs greater investigation.
Because of the economies of scale and the costs of transporting residues long distances, it may make more sense to process residues at a facility that already makes grain ethanol. At least one of the cellulosic ethanol plants currently under construction in the US is actually an extension to an existing plant. Because of this, utilizing wheat residues may be more economical than utilizing grass seed residues (in the latter case the crop residues are not paired with the crop).
If residues are used in addition to grain, it makes sense to evaluate the GHG impacts of the entire rotational system, which could include biodiesel crops as well. So if you have a corn-soybean or a wheat-canola rotation, it would make more sense to analyze the net-GHG emissions from the whole cropping system and the fossil fuels displaced by both the ethanol and the biodiesel. A study by USDA researchers did exactly this, looking at the net-GHG benefits of ethanol and biodiesel produced from different rotations and tillage-types, assuming 50% removal of corn stover. Biofuels (ethanol and biodiesel) from a conventional corn-soybean rotation produced a 38% improvement in GHGs, while a no till corn-soybean-alfalfa rotation produced a 43% improvement.108
Considering a reasonable estimate of a 20% net-GHG benefit from natural-gas fired corn ethanol plant alone, this suggests that integrating residues into first-generation systems would result in a substantial improvement in GHG emissions, particularly if best agricultural practices are used. To confirm this for the Oregon context, it would be very useful to conduct a similar study that examines the net-GHG flux for a bioenergy cropping system that includes biofuels produced from wheat, wheat straw, and canola or other oilseeds.
One important question that needs to be answered about these systems is whether enough biomass will be available to be burned to provide energy for the plant. As the relatively efficient heat and electricity generated from burning residues is a more important source of fossil fuel displacement than the liquid fuel itself, this should ideally be prioritized over simply maximizing liquid fuel production. Since cellulosic ethanol production leaves behind a high-lignin residue, the question is whether plants can be optimized to run purely on the energy produced from the residue without needing to burn any stover or straw directly. This may in fact be feasible as the company constructing an integrated corn/corn residue cellulosic-ethanol facility in Emmetsburg, Iowa claims that they can reduce natural gas use by 83%.109
Oregon potential: Agricultural residues represent the largest quantity of available biomass in Oregon, up to 45% of its current potential. Most of this is residues from wheat and seed grass.
A 2000 evaluation of the potential for cellulosic ethanol in Oregon estimated over 2 million bone dry tonnes (BDT) per year of wheat residues (based on a conversion factor of 2.3 tons per acre) generated in the state. After estimating how much residue would need to be left for soil needs (approximately 40-60% depending on region), there were around 1.4 million BDT per year available for ethanol production.110 Using the National Renewable Energy Laboratory estimate of 60 gallons per ton this would produce around 84 million gallons of ethanol.
The same study estimated that Oregon produced about 1 million BDT per year of grass seed straw, almost entirely in the Willamette Valley. About half of this is exported to Japan, and the rest is either burned or mulched into the field. If half of what is not exported could be sustainably used for ethanol production, it could produce another 15 million gallons.
6.3.3 Woody biomass
Forest thinnings, slash and residues
With over 28 million acres of forests, Oregon would seem to have a vast potential for woody biomass production. Determining how much can be sustainably harvested is a far trickier proposition, however. 31% of Oregon’s forests are reserved and closed to timber production; 33% are multi-use forests that mix timber harvest with other goals, such as recreation; and 36% are primarily devoted to wood production.
Because of the high economic value of wood that can be used as timber or other products, most of what would be available for biofuel or energy production is what is called “un-merchantable material,” fragments that have no easily quantifiable economic value. In addition to the slash and other unused biomass from timber operations, there is a growing need to manage forests to reduce forest fires. Years of fire suppression have left millions of acres essentially overloaded with biomass and at risk of environmentally damaging fires. Thinning and removal of biomass from these forests would improve forest health and provide a substantial supply of biomass for energy production. While there are clear environmental benefits to greater utilization of forest biomass, there are also real sustainability concerns.
Slash and Residues: Similar to agricultural residues, slash and other “unmerchantable biomass” serve a range of vital functions for forest health and ecology. Where intensive logging operations already remove more timber than is advisable to maintain forest integrity and biodiversity, creating a new incentive to remove everything that is left could have devastating consequences. Clear guidelines for the sustainable removal of biomass need to be developed and followed.
Forest thinnings: Because much of the thinning of forests will take place on multi-use and federal lands, it is especially important for environmental concerns to be answered to avoid a public backlash. In addition to the concerns raised above about what the optimal level of thinning is, the logistics of biomass removal pose serious environmental questions. The first will be the need to build roads and other infrastructure to allow the removal of tens of thousands of tons of wood from forests. None of the current studies of using forest thinnings for biomass have addressed the question of how much infrastructure would be required or the long-term impact. Road-building has a clear and documented impact on biodiversity and can have a profound effect on the character of a forest as more people are given easy access to areas that were previously inaccessible.
| Policy Recommendations - Forest Certification and Greenhouse Gas Benefits: |
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| All calculations of the net GHGs for biofuels are based on a key assumption: that the carbon released from burning the biomass is recaptured from the plant. With agricultural products and energy crops this is clearly a reasonable assumption. It is not at all clear that this will be the case for forestry. Considering the huge amount of carbon stored in forests over decades, even if clear-cutting or other practices are not used, enough carbon to outweigh the displacement of fossil fuels may be released. As biomass utilization will increase the economic pressure to use forest resources more intensely, the possibility that forest biomass use may contribute to, rather than help solve, global warming is very real.115 Determining the net GHG impact of biomass removal (including reduction of fire risk) is difficult. Until this area is more fully understood there is a simple policy option to provide at least some assurance. This would be to ensure that all biomass used is sourced originally from third-party-certified sustainably managed forests. The Forest Stewardship Council, a third-party certifier, already does chain-of-custody tracking of products for mill wastes, so it should be possible to identify the quantities of sustainably produced biomass that are available. Particularly over the next ten years or so when there is likely to be at most only a few cellulosic plants constructed in Oregon, it would be perverse to provide government incentives designed to reduce global warming to products that may be contributing to it. It is strongly recommended that only biomass from third-party-certified sustainably managed forests or from federal forests that have developed scientifically sound and rigorous sustainability criteria be allowed to qualify for any state-level incentives or tax breaks. Plants intending to use woody biomass that receive funding or tax breaks from the state should also be required to use only certified biomass. |
Another intrinsic problem is that once thinning of a certain area is completed, repeated thinning will not be necessary for years to come, while production facilities are fixed in place. The concern is that the economic pressure to produce more biomass from areas immediately around the plant would result in the overexploitation of forest resources and a loss of their natural character. For example, an Oregon State University study of woody biomass suggested that statewide, “1.0 million BDT (bone dry tons) per year could be available for 20 years.” With hundreds of millions of dollar in initial capitol costs and a lifespan of 30-60 years,111 the obvious question is what feedstock an ethanol plant will use after the 20 years it takes to finish thinning. Pressure to convert natural forests over to more plantation style management or even short-rotation woody crops may be intense. While it may be possible to utilize forest thinnings in a sustainable manner, these questions need to be answered before any construction begins. Particularly for any use of biomass from state and federal lands, sustainability guidelines and plans need to be developed to cover the entire projected lifetime of the plant and not just the timeline for thinning.
Greenhouse gas impacts: Based on comparisons with other cellulosic biofuels, it is likely that biofuels from sustainably extracted forest residues would have a very positive GHG balance, likely greater than those from agricultural wastes. This assumes that there is no net loss in biomass from the forest and that biomass use doesn’t create incentives for deforestation, which would rapidly wipe out any gains. While thinning obviously reduces the carbon stored in the forest, implying a GHG penalty, it should reduce the possibility for catastrophic fires that release large quantities of GHGs in a short time. More research into the net impact of these different factors is needed.
Oregon potential: Oregon has nearly 3 million bone-dry tones (BDT) per year of forest residues available, although only a portion of this can probably be used sustainably and economically for biofuels.112 Studies have estimated between 1.3 and 2.5 million BDT per year from harvest residues,113 but even at these levels extraction would need to be carefully examined for its impact on biodiversity and forest health. Assuming a conservative million BDT per year at 66 gallons per ton, this could produce 66 million gallons of ethanol. Estimates on how much forest health thinning would be available range from .8-7.3 million BDT over 20 years.114 While the upward levels of this range could produce around 500 million gallons of ethanol a year, the question remains what all of that biofuel production capacity would be used for after the 20 years is up. The lower end of the range, which still could be tens of millions of gallons a year, is likely more feasible.
Wood residues/waste
Residues from mills are another source of woody biomass that might be available for use as bioenergy in Oregon. These have the advantage of already being at a centralized plant, rather than disbursed throughout the forest. As waste products, full utilization of these resources for energy provides clear environmental benefits by displacing fossil fuels without putting more pressure on lands.
Greenhouse gas impacts: Biofuels produced from wood wastes would be expected to have a high GHG benefit, assuming that the wood was harvested in a sustainable manner and not the result of deforestation or practices that reduce overall forest health.
Oregon potential: Oregon mills are already extremely effective at utilizing wood waste residues. For example, out of nearly seven million bone-dry tons of mill residue generated in 2002, barely ten thousand went unused. Biofuel feedstock would have to compete with existing uses for materials, which may be able to outbid them. There may be other sources of woody biomass waste that are available in small, but substantial, quantities across Oregon, including mixed waste paper, paper mill sludge, garden and park waste, and construction and demolition waste.
| Policy Recommendations - “Roving” biomass-to-biofuel production facilities: |
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| Given the concern that fixed-in-place production facilities may place economic pressure to continue thinning biomass from areas immediately around the plant after it’s no longer sustainable to do so, Oregon should study the feasibility of smaller-scale production facilities that could be dismantled and moved to an area where sustainable harvest could occur. |
6.3.4 Algae
The feedstocks discussed in this paper so far are limited by the relatively large quantities of land that are required to produce them. The fact that this land has many competing uses makes this problem particularly acute, and is the greatest limitation on expanding biofuel production. The use of microalgae as a feedstock promises to get around this problem. This is because given light, water (including saltwater) and carbon dioxide, algae can reproduce it itself at an incredible rate, and certain types of algae can be composed of up to 50% oil. This oil can then be used for biodiesel production, although the algae could also be used for ethanol, biogas or burned for electricity.
The fact that algae can use saline water opens up huge areas of the country for possible production, which are also the same areas that are most limited in their ability to produce conventional feedstocks. The fact that algae requires CO2 is also a major plus, since CO2 captured from coal-fired power plants could be used to produce algae, which, while not permanently sequestering it, would substantially increase the amount of energy gained from the same amount of CO2. But it is the incredible yields of oil that have been suggested for microalgae that make it such an attractive option.
Much of the basic research on using algae for biofuels came from the USDOE’s Aquatic Species Program, which ran from 1978 to 1996, where they attempted to grow high-oil yielding algae in open, saltwater ponds in the desert. That program estimated that algae could produce up to 15,000 gallons per acre, hundreds of times more than any other feedstock, although they never achieved yields in this range.116 Even at a fraction of this yield, algae biodiesel has the theoretical potential to displace a huge proportion of our fossil fuel use, with only minimal use of land that isn’t suited for other types of agricultural production.
Despite its promises, the Aquatic Species Program also identified some major challenges that needed to be overcome. The open-air ponds they used would soon become dominated by local species, which crowded out the high-productivity strains they grew in the lab. Cold nights (typical in deserts and arid regions that also get the best sunlight) also drastically lowered yields.117 This can be overcome, but developing closed-pond systems, which regulate temperature and are still cost-effective, will be a challenge. Substantial research has also gone into photo-bioreactors, essentially big cans with a light in the middle where the algae can be grown in more controlled conditions. But these have much higher capital costs and their own set of technical hurdles, including assuring that the light reaches all the algae evenly.
A number of companies are working on innovative projects to use algae for biodiesel, but at this time there are no pilot-scale plants producing biofuels from algae, unlike with cellulosic ethanol (there is also reason for skepticism as there have been allegations of fraud; at least one South African company has made outlandish claims of success).118 That said, some interesting algae ideas include harvesting wild algae from municipal waste, using geothermal heat to keep the algae at a constant temperature,119 and incorporating algae production into a biorefinery with an integrated feedlot.120 Whether any of these ideas will prove to commercially viable and on what scale is not clear at this point.
Greenhouse gas impacts: While the GHG benefit would be presumably very high due to the high yields and use of waste CO2, until a viable production process is proven the GHG reductions will be unclear.
Oregon potential: Some areas of Oregon may have enough sunlight year round, but cold nights and winters would likely prevent the use of low-cost open-air ponds. More academic research on algae would be valuable.
