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A Canadian Perspective on Land Management Risks Associated with Biofuels and their Production
By the Alberta Agriculture and Rural Development. This document is part of the Capturing Feed Grain & Forage Opportunities 2007 Proceedings - "Farming for Feed, Forage and Fuel".
Key Points
- Biofuel production is an opportunity for Western Canadian Agriculture, but the changes necessary to be successful in this new industry have conflicting objectives and the changes are not without risk.
- The demand for biofuels will pressure and compete for lands currently used in food and feed production in both the US and Canada. This will cause change in land use and management.
- Most of the risk involves the quantities of feedstock required within the delivery region of the biorefineries and the production intensity required to deliver it.
- Management for high yields will be necessary in feedstock, feed grain and food production as high producing crop land will be at a premium. High intensity cropping systems with requisite high inputs will be required.
- Forage and pasturelands will be sacrificed to grain and biomass production. This will be problematic, environmentally.
- Livestock production will be moved to marginal land, which is environmentally fragile.
- The greatest risk of all is the rapid advancement of the industry without basic knowledge that can be used for sustainable development on a site specific basis.
Energy is now another ecosystem benefit that includes food and feed production, erosion control, improved water quality, carbon sequestration and wildlife habitat that is derived from agro ecological landscapes. Biofuel feedstock production and feedstock and co-product utilization will be opportunities for the agricultural sector in Canada. A positive impact of biofuel development is that feed and fuel prices may increase enough to entice investment in agriculture, which has handicapped research and development. Canada lags behind other parts of the world in biofuel development and accurate information related to biofuel systems; the lack of valid and verified knowledge constitutes a risk. That is the knowledge about production, utilization and processing is given to the industry in terms of climates, production systems, crops, resources and economic scales relevant to other countries. This information is being translated into Canadian or Western Canadian terms with very little basic knowledge and research to verify it.
Biofuels have become prescribed solutions to global environmental risk. There are three overarching risks that are interrelated and sometimes conflicting. They are: global loss of sustainable food production and human habitat due to climate change; increasing greenhouse gas (GHG) emission that causes climate change and instability; and the economic consequences of not being energy self sufficient as world energy consumption and fossil fuel demand increase. Fossil fuels used in transportation and heating are the major GHG emitters so reducing use of fossil fuels is important in mitigating GHG emission. Canada is self sufficient in energy, but our energy prices are influenced by world demand so energy cost is as problematic for farm-gate inputs and operations as it is for operating vehicles for urban transportation. Thus, Canadian biofuels have to be cost competitive with fossil fuels or market demand will be small. World demand for fossil fuel energy continues to grow at a much greater rate than can be significantly affected by biofuel production alone. In order to make significant impacts in reducing GHG emission many other mitigation strategies will have to be put in place along with substitution of biofuels for fossil fuels.
Uncertainty abounds in the unknown effects of change in land use and management due to the requirement for biofuel feedstocks. That is significant amounts of land will have to be taken out of food and feed production to fill biofuel demand. Risks to the survival of parts the livestock sector and infrastructures developed to support it increase due to higher costs and lower stability in traditional feed supplies. The biofuel industry revolves around refineries and plants. Plants must be large to reduce cost of production. The economics of plant management dictate reducing transportation and handling costs, which results in intensified production within 100 km proximity of a plant, increasing competition for land, feedstock and water; waste disposal is often an issue. The effects may be displacement of current crop diversity, increased fertilizer use, reduced water supply and reduced length of crop rotation. In theory, there are always perfect solutions to the issues, but in practice cost of production is the deciding issue, solutions may be conflicting and alternative solutions may not be positive. Thus, site specific research and knowledge is important to local sustainability.
Feedstocks and Their Relative Merits
Generally there is agreement that liquid biofuels can replace fossil fuels because they are renewable through plant photosynthesis, while fossil fuels are not renewable, at least within human life spans. However the quantity of fossil fuel displaced, on an energy-equivalent bases, must be greater than that required to produce the biofuel, taking the crop production, process, all inputs, co-products and energy density of the ethanol or biodiesel product into account compared to the conventional gasoline, natural gas, coal or diesel etc. that the biofuel replaces. Net energy balance (the energy contained in 1 l of ethanol minus the energy required to produce it) is a valid parameter so long as comparisons are made using equivalent systems boundaries. Rankings made on the basis of net energy balance, and ratios of energy inputs and outputs are not identical to net GHG mitigation potential, because the different fossil fuels have different energy densities and follow different pathways to end use.
| Table 1. Comparison of alternative biofuels with gasoline for energy input:output ratios | ||||
| Corn-ethanol | Wood-based-ethanol | Canola bio-diesel | Gasoline | |
|---|---|---|---|---|
| Energy Density (MJ/l) | 21.3 | 21.3 | 32.9 | 33.5 |
| Fossil fuel energy inputs (MJ/l) | 17.0 | 3.4 | 19.6 | 41.3 |
| Fossil Fuel input: biofuel output energy ratio | 0.80 | 0.16 | 0.60 | 1.24 |
| Cost of GHG reduction (US$/t CO2 equiv.) | 188 | 34 | 30 | |
| After Jaeger et al. (2007) Special report 1078. Oregon State Univ. Extension Service. July 2007. | ||||
Based on corn belt-yields and production practices the net energy balance for grain ethanol is 6.98 MJ/l compared to cellulosic ethanol from stover at 16.74 MJ/l .The percent reductions in GHG emissions from E10 gasoline/vehicle mile is 2% and 9% for corn grain and corn stover, respectively (USDA-ARS 2006). Generally speaking US corn-belt corn, German canola (biodiesel) and US Switchgrass (cellulose) reduce GHG emission by 22%, 68% and 91%, respectively (Bourne 2007). These latter values are based on optimum yields and typical inputs for areas in which the crops are grown and processed.
In general the examples represent the big differences among feedstock functional groups. The efficiencies shown in Table 1 for corn, wood and canola are based on yield and input assumptions valid for Oregon and are highly affected by yield. It indicates that total energy inputs, in the case of canola compared to corn, may have to be high in order to get a greater energy return. The biofuel product, biodiesel has a higher energy density than corn ethanol and the oil yield per ha. is relatively high. The canola example most closely reflects Western Canadian conditions. In Western Canada wheat will have a much lower grain and starch yield per ha. than Corn Belt corn, so we might expect a much wider difference in efficiency between Western Canadian wheat-ethanol and canola biodiesel in favour of the biodiesel. Published cellulosic efficiencies almost always assume low inputs and high yields, which are often not true when site-specific data is used.
Grain-ethanol - The Canadian domestic demand for ethanol is based on a renewable fuel standard (RFS) for E5 ethanol/gasoline blend by 2010. Currently this amounts to 2.4 billion l of ethanol. About 66% would come from prairie wheat. Depending on wheat yields this would require between 1.3 to 1.86 million ha of wheat. American grain ethanol production is expected to reach 36 billion l by 2010 even though building of new plant capacity is slowing down. The only US government mandated requirement is for 28.5 billion l by 2012. American grain ethanol will likely hit its’ capacity limit at about 53 billion l if an RFS of E10 is mandated. However, the US Department of Energy (DOE) is predicting that 275 million t of new grain and biomass feedstocks will be required for liquid biofuels by 2017 in order to fulfill an expectant requirement for 133 billion l of ethanol. Both in Canada and the US the extra grain area will come from other crops. Thus no matter what happens in Canada there will be an increased demand for Canadian grain to fill the world feed grain and food grain market. Competition for land will dictate that high yields and the required high inputs will be needed, because highly productive land will be at a premium.
High yield is really important, because high yielding crops tend to be efficient in terms of dry matter and bioenergy produced per unit input. More land is required per unit prairie wheat than corn-belt corn. Corn yields will be 8.0 to 9.2 t/ha; wheat suitable for ethanol production in Alberta yields 3.3 t/ha. Corn-ethanol conversion ratios are about 380 l/t; wheat ethanol conversion of 360 l/t. Conversion ratio is impacted slightly by climate and agronomic factors. However, the grain-ethanol process is mature and there are no large gains in starch conversion to ethanol expected or at the very least gains will be marginal. Transportation costs and energy expenditures are usually more efficient if fewer miles and trips are taken in the harvesting process. Corn drying uses fossil fuels whereas wheat is usually harvested dry. No-till cropping systems are used to save fuel and to sequester CO2, which negates a portion of fossil-fuel emission. Until adoption of zero tillage and high corn yields experienced in recent times (9.2 t/ha) fossil fuel displacement by grain ethanol was marginal for environmental benefit. No-till reduces machine operations and adds a short-term C-sequestration benefit. Tighter oilseed-grain rotations may be efficient but not necessarily sustainable for food production. Grain based systems which don’t produce high yields year after year (e.g. corn-soybean-alfalfa sequences vs. corn-corn or corn-soybean) will produce less ethanol than perennial crops with lower conversion ratios on a long term per ha basis. However, corn-corn rotations produce 10% less yield than corn-soybean rotations.
Biodiesel-oilseeds - The demand for biodiesel is impacted by the same demand factors as described for grain-ethanol. Thus more canola will be required for fuel, feed and human food. Biodiesel is more efficient that grain ethanol, because energy density is higher than ethanol and conversion rate from the raw product is higher. Oil content converts directly to the fuel used. Except for the use of fertilizer-N, canola is more GHG and energy efficient than soybeans as oil content of canola is twice that of soybeans. High oil yields are important as less land, resources, field and process-based inputs will be required per unit of biofuel produced. Because rotation is required to minimize canola disease problems, frequency of wheat or corn in rotation sequences could augment year after year energy production, while minimizing land use for biofuel production. Use of hybrid canola will allow tighter rotations, but risk of massive disease outbreaks, such as clubfoot, exist, especially within the biorefinery boundaries, where oilseed density will be high.
Biomass energy - Every aspect of a biomass based fuel industry is immature compared to virtually any other processing industry including grain-ethanol. However the North American demand for biomass is driven by the DOE prediction that between 590 and 636 million t of biomass will be needed to attain US biofuel targets by 2025. This quantity of biomass would require 20 to 40 million ha of dedicated biofuel crops depending on assumptions related to yield, conversion rate, species and location grown. Biomass can be used as an energy source through several energy-end products and management pathways and can be used in combination with grain ethanol operations to displace fossil fuels (natural gas or coal) in the heating and drying operations. The most abundant biomass source for ethanol production on a unit area basis is corn stover from the US corn belt states. The Canadian Prairie region produces a lot of straw residue (15 million t), but the yield available per unit area (1.8 t/ha) is not high, compared to corn belt stover (3 to 6 t/ha). Conversion rate for cellulosic ethanol production is about 300 l ethanol/t. Costs of production of ethanol from cellulose are at least twice those of grain ethanol due to the low conversion rate and harvest and transport costs. Harvest, transport, storage and collection of biomass-ethanol feedstock contributes $0.25 to $0.37 / l to the cost, so high yields of available straw within the collection area of the biorefinery is important. Pre-processing costs for cellulosic ethanol are greater than 40% of cost of production and 25% of the cost deals with moving the biomass to the refinery. This means that plants utilizing straw will be situated where straw yields are high and other sources of cellulose such as wood products are available.
Calculations of biomass to energy efficiencies have been based on yields determined elsewhere. In North America, switchgrass has been used as the example for calculation. In Life cycle analyses switchgrass and reed canarygrass displaced gasoline by 6.96 and 4.88 MJ/m2/yr compared to no-till corn-soybean rotations at 5.84 MJ/m2/yr; GHG emissions were reduced by 114, 84 and 41%, respectively. Perennial forage species require lower fossil fuel inputs as they don’t have to be established year after year; the warm season grasses like switchgrass require less fertilizer-N per unit of production; and they are superior to corn and wheat for carbon sequestration. However, switchgrass is not adapted to Western Canada. Yields of 11 t/ha are required. Yields of switchgrass and other native species used in Western Canada are half of that level.
It has been argued that large areas of marginal lands could be utilized for biomass production. It is likely that both potential yield and economically available area has been exaggerated. Problems of low yield and yield variability over years will dictate contracting or planting biomass crops on land of higher than lower quality so consistently high yields will occur. Because transportation costs of the bulky feedstocks are high, high biomass yield within an economical vicinity of the processing plant will dictate some fertilizer use.
Environmental and Sustainability Issues
Biorefineries do not have an environmental mandate. Their motivation is profit. Because of procurement and transportation costs biorefineries preferentially use feedstocks within 100 km of the base-location. This is because costs increase logarithmically with the distance from the plant. The same is true when moving byproduct out. Thus, large changes in agricultural sectors within the plant areas will occur. The bottlenecks to sustainable agricultural production and environmental consequences within the confines of the areas served by biorefineries constitute the future problem and risk. The biorefineries will be situated in areas of intensive production, adequate water availability and transportation centers.
A biorefinery to be built in the Red Deer area to produce 180 million l of bio diesel and 180 million l of bio ethanol will require all of the canola and 70% of the wheat from a 100 km radius (Westakawin to Carstairs and Rocky Mountain House to Hanna). Currently 44% of the land base is in pasture and hay, 31% in grain other than wheat, 17% in wheat and 9% in canola. Clearly, if this new plant and the existing plant are to survive a considerable change in the composition of land use and management will have to occur. If the feedstock were to come from Red Deer, Ponoka and Lacombe counties, a smaller area, a loss of 75% of the special crop area (peas), half of the tame hay and unimproved pasture would occur. The plants require 3 to 4 l of water per l of biofuel produced. The plants produce canola meal and distillers grain co-products approximating 60% and 36 – 40% of weight hauled in, respectively, which have to be trucked back out. There will be a lack of infrastructure.
Currently there is no refining capacity for cellulosic ethanol in Western Canada. There are six world class plants under construction in the US. A cellulosic-ethanol biorefinery will use any type of cellulosic material, but will use residues first, because they are assumed to have no cost of production; costs of production have been paid for by a primary grain or forest operation. A plant in the Red Deer area would be pressured to find feedstock resources close to the area because of transportation costs. A plant requiring cereal straw with an annual 114 million l capacity would need 380,000 t of biomass dry matter. Red Deer, Ponoka and Lacombe counties, produce relatively high yields of straw, but about 25% of the straw produced would be needed to prevent soil erosion. If cattle populations are to be maintained about 50% would be needed for bedding and feed. That leaves the plant short about 194 thousand t of straw or residue to be made up from other sources or outside the district.
It is unlikely that all grain producers will sell and transport straw, but beef cattle production may be reduced, leaving some surplus straw. Under the scenario of beef cattle reduced by 30% and 25% of the cereal area under contract, the plant would have to find even more straw, 298 thousand t. The plant could contract outside the area at higher cost and in time of drought would not likely be able to operate. Thus the biorefinery would need alternative biomass supplies to mitigate risk. Forest waste and dedicated biomass are possible and perhaps necessary solutions. The plant could contract or rent land to grow perennial biomass. At an optimistic delivered yield of 5 t/ha that would take 59 thousand ha. or 26 % of hay and pasture land out of production. To take the biomass out of grain production would be self defeating if the straw was a desired commodity.
Specific Issues
Change in land use - This issue is easily glossed over until one understands the massive land use changes predicted in the US. Even if Canada is self sufficient in energy, potential world markets for meat are expected to increase based on international demand, so demand for feed grains in North America should be stable. Therefore grain production will have to be more intense and require more land in both United States and Canada. The centre for biomass production in the US is expected to be the south east. This area will allow 365 days of dry matter production from C4 plant species, which will achieve high yields necessary for economic production. Corn production will be shifted as far west as moisture will allow and on to forage and pasture land (approximating 24 million ha). Area lost from hay and pasture land would approximate 2.5 times the hay, pasture and range lands found currently in Alberta. This constitutes a potential problem for the US, because the current western rangeland is predicted to be hit hard by heat and drought of global warming. The dilemma is “How to get governments and beef industry interested in investing in research on improving production on remaining forage and pasture lands to support economical ruminant industries?” Biofuel co-products may be a partial answer, but only meet parts of the ruminant diet and because of transportation costs can only be used in dry lots.
Breaking of perennial forage lands - Societal benefits provided by grassland have been valued at $232/ha compared to cropland at $92/ha. The extra benefit was attributed to less GHG emission, soil and water conservation and waste management. When the prairie was broken until current cropping practices reached new soil carbon equilibrium about 30 to 40% of the original soil carbon has been lost. Replacing cropland with perennial grassland results in soil sequestration rates of 400 to 1200 kg C/ha/yr. Root material of perennial crops accumulates faster and degrades slower than that of annual crops. Alfalfa has the ability to procure nitrate below the rooting depth of annual crops; grasses, in particular, improve soil aggregate stability. Soil aggregation enables soil some resistance to erosion and loss of soil carbon. Aggregate stability can be lost in as few as two years after breaking. Thus once lost the benefits of perennial grasslands may never be replaced, particularly when substituted by intensive annual crop production. The long-term reduction in grassland needs to be weighed against biofuel benefits. This has not been done.
Overgrazing - The most productive forage lands may be removed, at least within close proximity of the refinery. It is difficult to imagine maintenance of a beef cow herd in current numbers. Rangelands are at capacity so if cow herd expansion occurs again it will have to occur on arable or cultivated land. More likely less productive land will be overgrazed. Overgrazing results in erosion on fragile lands and carbon loss, although quantification of these losses has always been difficult.
Disposal of distillers grains by feeding on pastures will cause soil nutrient overloads, leaching and runoff of nutrients. Because of the dry, short growing season in Western Canada and grazing per se plant nutrient uptake rates will not accommodate the extra nutrient loads and livestock recycling of nutrients at feeding sites. This scenario has been documented on dairy farms in the US North East where dairy herds are fed grain and then turned out on pasture. Soil and forage phosphorus and potassium levels become elevated and milk fever becomes problematic. If carried out on marginal lands and range the changes in soil nutrient status will impact biodiversity with Kentucky bluegrass and quack grass invading and dominating stands.
Reduced length of crop rotation - Crop rotation impacts on yield are really about direct and indirect effects of maintaining soil organic matter. A direct effect would be incorporation of straw to increase organic matter; an indirect effect would be impact of tillage or fertilizer on organic matter balance. Losing soil organic matter implies loss of soil carbon, reduced ability to store soil nutrients and water and predisposes soil to erosion through loss of soil aggregate stability. Long crop rotations that include legumes and or forages (e.g. wheat-canola-forage-forage-forage-wheat-canola) reduce the rate of soil organic matter loss and help to build yield potential and stability. Soil organic matter levels can be improved to a point through increased use of fertilizers, which require fossil fuels to fabricate. Short rotations (canola-wheat-peas) require fertilizer to improve or maintain soil organic matter levels. No-till in combination with fertilizer-N has been beneficial in these short rotation cropping systems to maintain a certain level of organic matter and therefore soil sustainability and health.
Removal of cereal residue - Risks involved with removal of cereal straw and stover lie in the year to year yield variability and lack of site specific knowledge of yield and risk associated with frequent straw removal. Current research, which recommends minimum residue levels, is based only on minimizing erosion and does not take soil carbon maintenance into account. With rare exceptions estimates of available cereal residue have used provincial averages based on calculation from grain yield. Harvest indices vary from year to year and straw availability needs to be assessed on the basis of soil texture, landscape and soil moisture attributes. About 1 t/ha of straw is required to prevent soil erosion, but residues are more important in drought prone areas as residue reduces soil moisture loss and maintains a desirable soil temperature. In drought years no straw may be available after erosion and animal requirements are taken into consideration.
Current research indicates that some removal of straw residues can occur without sacrificing sustainability so long as adequate fertilizer is applied to maintain soil organic matter levels. Above ground plant residue degrades much more quickly than root material. Choosing crops with vigorous root growth characteristics as well as biofuel conversion characteristics will be important. Maintaining continuous leaf canopy covers by using crop combinations that allow for relay cropping and practical intercropping, while allowing residue removal would be particularly helpful. Increasing seasonal light interception enhances or increases total season ecosystem photosynthesis and therefore carbon sequestration. These systems may be beneficial in areas of sufficient moisture to allow more than one crop during gaps in leaf area in either spring or fall. The cover crops may not provide much revenue, but will compensate and or prevent soil carbon and nutrient loss.
Residue left after cellulosic-ethanol production is relatively large as conversion rates may be low. The residues are highly lignified and this protects the associated carbon from microbial degradation. Residues of this sort returned to the soil could be highly beneficial to maintenance of long-term soil carbon stores.
Use of dedicated perennial feedstocks on marginal lands - Dedicated perennial biomass will be required if the Canadian renewable fuel standard increases to 10% or E10. This may occur by 2015. At that level of demand grain and oilseed production within Canada will not keep pace without seriously harming food and feed production. The DOE recommendations that 25 % of US energy must come from renewable fuels will require a lot (400 million t) of energy-dedicated biomass. It means that technology will progress for cellulosic-ethanol and other energy paths that use ligno-cellulose. In Canada, particularly Western Canada, we don’t have suitable perennial species with defined quality characteristics and high enough yield for economical biomass production. The idea that any perennial grass from all marginal lands is suitable does not stand up on the basis of transportation economics or sustainability. Marginal land is marginal for a reason. Grass will grow, but at low yields caused by low soil nutrients, low water holding capacity and above all a short growing season. Canadian biomass yields are not competitive with US production, even if US yields are exaggerated. Research on species development and management for biomass production as well as site specific analyses on dedicated biomass for cellulosic Biorefineries is required.
Plantations of perennial forages can be harvested sooner than forest plantations. Perennial grass stands can be developed in 2 to 3 years compared to 10 to 30 years required for tree plantations. However, establishment of suitable perennial grass may be problematic. Native species often have germination issues and other species like Miscanthus have to be sprigged in. Time lags in the establishment phase of perennial grasses are periods of massive carbon loss and expose soils to serious erosion, particularly on marginal lands.
Compatibility with current crop and livestock systems - In order to maximize yield and concentrate production geographically, perennial biomass crops will likely be produced in large plantation areas close to refineries. They will be harvested once per year. While maintenance will require labour, these crops won’t require a lot of farmers. They will not likely be compatible with grazing and will occupy some of the land currently used for forage production. Some interaction with beef cattle may occur through use of residues not harvested or lost. This residue material will have low forage quality.
Introduction of invasive species - High yielding, species suitable for growth in monocultures and specifically bred for particular end uses are required for biomass production. These species tend to produce well when grown alone, but not when grown in competition on marginal sites. Introduced species, which are aggressive and shed seed prior to harvest would be invasive and in short become problem weeds. In fact some species considered for feedstocks, such as Johnsongrass, are noxious weeds. Species, such as Miscanthus, used in biofuel production are sterile hybrids and therefore not easy to grow. They cannot be spread by seed, which is an advantage. Wild Miscanthus types are available. These may be hardy enough for growth in Western Canada, but are more likely to be invasive threats.
Conclusion
Most of the risk associated with biofuel production deals with intensive production and processing of feedstocks in the feedstock procurement area surrounding biorefineries. The massive quantities of feedstock required and the costs of transportation mean intensive production of high yielding feedstocks is needed. In these areas radical changes in land use and adjustments to the livestock industry may occur. Loss of land used in perennial hay and pasture land will be at the root of environmental issues. Tightening of crop rotations to produce cereal and oilseed feedstocks could result in loss of soil carbon and reduced sustainability. The greatest risk of all is the rapid advancement of the industry without basic knowledge that can be used for sustainable development on a site specific basis.
References
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