Hemp has been promoted as a promising alternative crop for the future. The federal government institutionalized alternative-crop research and development programs as an integral part of national policy in 1990.
These new programs have created standards for evaluating the potential of alternative crops. The same standards apply to the potential use of cannabis plants as a source for industrial raw materials. Given existing research into other alternative crops, why not hemp?
Because of these new programs, advocates sometimes overstate the challenge of having hemp adopted as a source of industrial raw materials. Hemp promoters work hard to present arguments that meet optimum standards. These standards are premature.
The stages of the adoption process for any promising innovation flow from research through development and commercialization, culminating in adoption. No one knows a plant’s optimum standards until after research and development. The question is, does a plant meet the standards which qualify it as a promising research subject? If hemp has characteristics similar to or better than other potential crops, there is no valid justification for officially ignoring it any longer.
In our continuing coverage of hemp, Jon Gettman has authored a three-part series on its viability as an alternative crop to be included in the Agriculture Department’s investigations. Part One will review the current existing biofuels program and hemp’s promising potential as an energy source. The second and third parts, which we will publish over the next several months, will review the developing technologies and the new hemp byproducts they can produce and explain how these new programs provide an irresistible and irrefutable argument for a legal hemp industry in the United States.
The key to lobbying Congress and executive agencies for hemp development is to discuss it in the context of existing government programs, to get government officials on record justifying hemp’s exclusion and to refute them with information from official sources. This series will provide the tools for this job.
Hemp for Fuel
The disagreement between Ed Rosenthal and Jack Herer in the April 1995 issue of High Times is fairly instructive. Rosenthal is skeptical of hemp’s energy potential and criticizes some of Herer’s claims.
Hemp does require fertilizer: Rosenthal is right about that. Herer’s claim that hemp does not require much fertilizer is based on old Agriculture Department reports from fields where the hurds were recycled into the soil. Rosenthal is also correct that the future of US policy leads toward diversification, and that no one source will meet all of our energy needs. Herer also engages in frequent hyperbole and is so enthusiastic about hemp’s potential that he sometimes overstates his case.
That said, Jack Herer and Lynn Osburn are right on the mark when they claim that biomass is the energy source of the future, and that hemp has exciting contributions to make to bioenergy development. Herer is a promoter, the archetypal twentieth-century hemp-oil salesman. But unlike the snake oil of the preceding century, Herer’s elixir lives up to most, if not all, of its promoter’s claims.
The key to hemp’s potential as an energy source is new technology. To explain this requires an understanding of how developing technologies can extract the energy value of the molecular chains within the seed and stalk of the cannabis plant. Rosenthal is correct that hemp has little or no value as an energy crop today; Herer is correct that it will have considerable value as one in the future.
Changing technologies provide the answer to how we get from here to the hemp-friendly future. Biomass for energy is now a major policy of the US Government. Alternative crops are in development as future energy sources, as is solid municipal waste.
The United States now has 60 million idle acres of farmland (an area almost as big as Oregon), including 34 million acres in conservation programs, which the Department of Agriculture wants to see devoted to erosion-resistant energy-crop farming. Energy farming does not require the use of marginal land, but hemp’s versatility may also help transform marginal land into productive acreage.
Seed oil is a viable fuel source now. Louis Wichinsky, who powers his car with vegetable oils (“Hemp-Ready Car Takes Off Across America,” Apr. ’95 HT), wasn’t the only one who realized during the 1970s energy crises that biodiesel fuel was the trend of the future, and the US Government now knows it’s trying to catch up in this area of research.
Rosenthal’s primary issue remains unchallenged. The massive scale of potential bioenergy production presents considerable environmental problems. These problems must be solved before hemp, or any crop, can satisfy large percentages of US energy needs, and these issues are now being addressed by current research.
US Biomass-for-Fuel Policy
The Department of Agriculture (USDA) states in the foreword of their 1992 Yearbook of Agriculture that: “It is important for America to lead in the research and development of alternative uses for agricultural products.” A major part of these efforts is devoted to the development of bioenergy crops.
The USDA hasn’t exactly considered hemp as a source for fuel, but it is considering other crops and has developed various standards. Hemp meets those standards. The issue in the hemp-for-fuel debate is not how, but how long before the federal government realizes the benefit of investing funds in hemp research.
The practical goal is to develop energy crops to provide 10 to 30 percent of the country’s energy needs and to supply additional environmental benefits. There are also other national interests that can be satisfied by energy crops, including economic, budgetary and national-security concerns.
In 1990 Congress authorized the USDA to set up a division, the Alternative Agricultural Research and Commercialization Center, to promote and assist in the development of alternative agricultural crops.
Research into natural fuel sources suggests that hemp has two valuable contributions: stalk and seeds. This gives it an advantage over many other experimental crops that produce only one raw material. Hemp has other advantages over traditional crops such as corn, despite the multiple uses for corn byproducts. Any attempt to develop alternative uses for food crops will increase food prices, by increasing demand for the crop and because of the complicated economics of crop-support programs.
The USDA’s Office of New Uses and Energy oversees the biofuels initiative and coordinates work among various federal agencies. The Department of Energy (DOE) also has a national biofuels program.
Development of Sources for Ethanol
According to the USDA 1992 Yearbook, “One solution to the problems posed by our oil-supply situation is homegrown energy. While this sounds good, in practice homegrown energy is a tremendously complex undertaking that will require a lot of work and experimenting.”
Cellulose is the basic component of plants. It is easily converted to sugar, and sugar is easily converted to ethyl alcohol. When conversion takes place in a still in the mountains, the product is called moonshine. When it takes place in an industrial plant, the product is called ethanol, and is used as a clean-burning fuel and petroleum additive.
Ethanol yields from cellulosic biomass have been increasing, and recently reached 60 gallons per ton, at a cost of $1.50 to $2 per gallon. Corn produces 113 bushels per acre, and produces 2.5 gallons of ethanol per bushel. US ethanol production has grown from 20 million gallons in 1979 to 1.1 billion gallons in 1993.
Corn cannot produce all the ethanol the United States can consume. Other sources are being aggressively researched. Wood chips are another source, but they are difficult to harvest. Agricultural residues and municipal wastes are also under consideration, and new types of crops are in development.
Herbaceous energy crops — which regrow from stubble, like hay does — and short-rotation woody crops — which regrow from stumps, like poplar — make up a new class of cellulosic bioenergy crops. Five variables provide the standards of competition for them: technical feasibility, availability of suitable land, economic viability, implementation and environmental impacts.
The Congressional Office of Technology Assessment reports that estimates of land area available in the United States for energy-crop raising range from 37 million acres (about the size of Georgia) to 250 million (as big as Texas and New Mexico). The theoretical yield is 6.6 to 8.8 tons of biomass per acre. Whether this is competitive with fossil fuels or not, it is the OTA’s opinion that “energy crops may still be desirable if other benefits — such as environmental advantages, offsets of oil imports or financial returns to the rural economy — justify the costs.”
According to the USDA, “The ethanol industry and some environmental groups maintain that ethanol production would be fully competitive with gasoline if the full environmental costs of petroleum production and use were considered. At these costs, which include human health problems, become more apparent, the ethanol market may grow significantly. As this process takes place, new research findings that improve production economics could result in a variety of other resources, such as dairy whey and wood chips, joining corn as feedstocks for the fuel ethanol industry in the United States.”
At some point, biofuels will contribute to a reduced demand for petroleum, contributing to lower or stable petroleum prices. The development of biofuels should not pit propetroleum against antipetroleum forces, but instead should improve US leverage with the rest of the world.
At three to four tons per acre, hemp would not seem competitive with the theoretical yields from herbaceous and woody crops, but no one has yet realized those theoretical yields. However, these are developmental crops slated for optimum environmental niches. The technology developed to exploit them will make hemp more competitive as an energy source.
The DOE’s Herbaceous Energy Crop Program is evaluating a number of grasses, including Bahia grass, Bermuda grass, eastern gama grass, Johnson grass, napier (elephant) grass, reed canary grass, rye, Sudan grass, switchgrass, tall fescue, timothy and weeping love grass. Legumes such as alfalfa, bird’s-foot trefoil, crown vetch, flatpea, clover and sericae lespedeza are also being investigated. At present, these crops are yielding 3 to 7 tons of biomass per acre. Fiber crop expert James Dempsey reports that hemp produces 6.6 tons of dry, unprocessed stalks (producing 17 percent fiber and tow by weight if processed). Hemp is competitive with other herbaceous energy crops as a source for biomass.
Corn won’t provide our bioenergy needs; nor will sugarcane, another cellulose-rich crop. If these crops were viable, then the government wouldn’t be experimenting with gama grass and clover. Solid municipal waste is 40% cellulose. Hemp stalks, though, are nearly 80% cellulose and pentosan (a sugar, also known as hemicellulose, convertible to cellulose).
The chemistry of transforming cellulose-rich natural products into ethanol is not new. The process, hydrolysis, is nearly 100 years old. A new process, enzymatic hydrolysis, is under development and will produce greater yields and fewer waste products.
Other technological developments that promise to bring down the cost of ethanol production include novel harvesting methods, crop management, separation-process improvements, improved enzymes, genetic-engineering advances and pretreatments that will also improve yield.
One of the complications in producing ethanol from natural cellulose sources is the need to remove the lignin, the natural glue that holds vegetable material together. The DOE has been working for several years on a process to directly convert ligno-cellulose to ethanol without removing the lignin first. The Terrestrial Energy Corporation research activity takes place at the Oak Ridge national laboratory in Tennessee, and will have a major effect on hemp’s economic viability as a source for bioenergy. Microorganisms are being developed there to speed up the conversion of cellulose and hemicellulose to sugars, which can then be converted to alcohol. The DOE hopes to cut the cost of ethanol from biomass to just 67 cents per gallon by the year 2005.
According to the conclusion of the DOE’s 1992 Yearbook, “Making liquid transportation fuels from biomass economically and in large quantities could provide the nation with a renewable source of fuel while reducing our dependence on imported oil. New technologies have made it possible to produce liquid fuels in large quantities, and in some cases the economics are becoming more favorable. However, the most important developments in technology and commercialization lie ahead. The greatest challenges are to learn how to utilize biomass material in a way that produces the maximum possible amount of fuel at the minimum cost.”
Bottom line: The United States has 60 million acres of idle arable land. Energy crops tend to prevent erosion, so the goal is to use those 60 million acres to experiment with different energy crops and different ways of integrating land and technology to produce energy. While the theoretical standard for bulk biomass production exceeds the standards for hemp production, hemp is very competitive with the actual yields of experimental energy crops. Factor in hemp’s diverse ecological adaptability, and it becomes a very appealing energy crop.
Diesel Fuel From Seed Oil
“The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in the course of time as important as petroleum,” declared Rudolf Diesel in 1912.
Alcohol fuels will not power diesel motors, but vegetable oil will. According to the DOE, “Biodiesel’s major advantage is that it is environmentally clean. Unlike conventional diesel fuel, biodiesel contains neither sulfur nor aromatics. Aromatics contribute to particulate emissions…. Biodiesel is biodegradable.”
In 1990, a French company displayed an engine that ran on peanut oil. At the end of World War II, the Japanese navy stored soybean oil to fuel the 65,000-ton battleship Yamoto.
Farmers are intrigued because unlike ethanol, vegetable-oil extraction requires no distiller’s license. The process requires less water and energy than ethanol production, and produces a high-protein meal as a byproduct. Oilseed fuels have a low sulfur content, are safe to store and do not cause skin ailments.
In the authoritative Oil Crops Of The World, oilseed-energy expert G.R. Quick reports that, “Initially, engine performance has been encouraging with most of these candidate diesel-fuel alternatives. Short-term tests on both DI [direct injection] and IDI [indirect injection] engines show that power output, torque and brake thermal efficiency on oilseed fuels were similar to those when the same engine was used on diesel fuel. Fuel consumption is usually somewhat higher due to the lower heat-energy of the oil.”
The problems with using vegetable oils to fuel direct-injection engines included start-up problems in cold weather and fouled injector tips in the engines after sustained operation. Technical aids can help with the starting problems, but the fouled injector tips are a result of high viscosity, and this could be a problem for hemp oil: Carbon builds up in the injector holes, interfering with the spray pattern of the fuel and affecting the combustion. Engine power declines and exhaust smoke and engine misfiring increase.
Viscosity is a measure of the oil’s thickness, particularly of its resistance to flow. Vegetable oil flows faster at room temperature, for example, than petroleum motor oil does. Relatively high viscosity is characteristic of vegetable-oil fuels (except for castor oil). One response is frequent maintenance, such as replacement of the injector tips. Another strategy has been to lower the oil’s viscosity by blending it with mineral distillates. Also, heating oils lowers their viscosity; fuel heaters can use engine coolant as a heating medium.
Blending and heating do not solve all these problems, and viscosity is not their only cause. Oils that have similar viscosities can produce injection-tip fouling at different rates. Oils with high unsaturated fats, such as linseed oil, are the most conducive to injector-tip fouling. An engine that will run for 100 hours on rapeseed or sunflower oil will last only about 10 hours on linseed oil. Hemp oil, unfortunately, is also high in unsaturated fats, and would seem unlikely to be competitive with other oils as a source of biodiesel fuel for direct-injection engines.
In the DI engine, fuel is injected directly into a combustion chamber. However, in the indirect-injection engine, the combustion takes place in an antechamber. Large tractors tend to be DI engines, while IDI engines are more elaborate and quieter.
Indirect-injection engines run on vegetable-oil fuels without significant problems. South African engineers have run unmodified Deutz tractors with IDI engines for 3,000 hours, with some attention to fuel filtration. Quick also reports similar results with Caterpillar tractors in Brazil. The two manufacturers have qualified their warranties in those countries, respectively, for machines operated on vegetable fuels.
Australian engineers have confirmed that even highly unsaturated linseed oil will fuel an IDI engine without problem, after testing an engine for 200 hours. Hemp oil, used as a biodiesel fuel, should be capable of operating indirect-injection engines without abnormal component wear to the engine.
Chemical Modification of Vegetable Oils
Vegetable oils have additional promise as a fuel source after chemists get their hands on them. They contain molecular structures called triglycerides, which are made up of fatty acids and glycerol, one of many alcohols. By 1938, scientists had realized that the fatty acids in vegetable oil were more valuable as fuel oil without the glycerides. During World War II, the Chinese made a crude form of such “veg-diesel” fuel using tung and rapeseed oil.
Their process has been refined and patented, and is called esterification. Quick explains: “The process involves the transformation of the large, branched triglyceride molecules of bio-oils and fats into smaller, straight-chain molecules, similar in size to components of diesel fuel.” The oil is filtered and preprocessed to remove free fatty acids. Then it is mixed with methanol and a catalyst, usually sodium or potassium hydroxide. The esters and the glycerols can then be separated from each other and purified.
South Africa has conducted extensive research on esterification. One response to the economic embargo in 1978 was a crash program to develop sunflower oil as an answer to their farm diesel-fuel supply problems. The bad news is that esters are organic solvents, and widespread ester-fuel specifications will be needed for large-scale fuel use. Esters also form crystals at cold temperatures. Many engine issues remain to be resolved regarding their use as fuel, but the good news is that the problems are worth solving.
Ester fuels do not cause injector-fouling in DI engines, and have consistently better characteristics. Esters can be used as an agent for mixing fuel with alcohol, and can be produced in small-scale plants. The viscosities of vegetable-oil esters are similar to diesel fuel’s. Esterification, though, increases the cost by up to 50%.
Price is thus the limiting factor. In 1992, biodiesel cost about $2 per gallon, diesel about 70 cents. Still, development continues. The Italian Ferruzzi-Montedison industrial conglomerate completed a 17-million-gallon-per-year biodiesel plant in Italy in 1992, and also set up a demonstration program in South Dakota.
According to the USDA, peanuts, sunflowers and rapeseed produce 75 gallons of oil per acre; soybeans give 40 gallons and cottonseed 20 gallons. Hemp yields 30 gallons of oil per acre. Over 50 million acres would be needed to supplant the 3 billion gallons of petroleum diesel fuel used every year for agricultural purposes.
Increasing petroleum prices, increasing oilseed crop yields and increasingly strict environmental regulations all encourage larger-scale biodiesel plants, such as a 3-million-gallon-per-year plant in Australia and a planned 7-million-gallon plant. Austrian farmers have successfully operated a seed-oil co-op, transforming their canola and sunflower oil into biodiesel for their own use.
Dr. John Irkerd of the Center for Sustainable Agriculture at the University of Missouri favors the small-scale approach for the near future: “There is a real possibility of community-level, if not on-farm, processing of the oil to turn it into a competitive substitute for diesel fuel for farm tractors, with the meal being used locally for livestock feed.” This might be a greater commitment than most farmers are willing to make, and large-scale plants provide tremendous technological sophistication, which is important for quality control of the byproducts.
According to the USDA, all the oil from oilseed crops is valuable to biodiesel efforts: “Currently the United States squeezes 13 billion pounds of oil from soybeans and another 1 billion pounds of oil from the corn crop each year. For both of these prime sources of vegetable oil, the crop is grown for other purposes, with the oil (18 percent for soybeans, 5 percent for corn) as a byproduct. Other potential biodiesel crops with a higher oil content include industrial rapeseed, canola, crambe, safflower and sunflower — all presumably could be bred for still-higher yields and oil content if biodiesel provided a market.”
Hempseed contains 35 percent oil, and like linseed oil has a high iodine value, an indication that it is high in unsaturated fats. Many alternative crops have seed-oil content between 30 and 50 percent, so hemp is competitive. Seed-oil yields vary. Jojoba plants provide a yield of 3,000 pounds per acre, but only after the shrubs are 10 years old. Rapeseed produces 2,500 pounds per acre, and crambe 1,500. The British report seed yields from hemp of 1,200 to 1,500 lbs/acre in India. (The Council of Scientific and Industrial Resources in 1950 published a 13-volume encyclopedia titled The Wealth of India, which contains technical specifications on thousands of plants and raw materials, including cannabis.)
Potential Environmental Impacts of Bioenergy Crop Production
Generally, energy crops require less intensive care than conventional crops. Heavier and deeper rooting patterns allow the soil to be utilized at a greater depth, increasing access to nutrients and water. The heavier rooting places more carbon in the soil, improving the nutrient-release capability of the soil. Many energy crops also consume less input energy (such as light) per unit of energy stored than do many specialty-plant components. Grasses and shrubs require less fertilizer because they are not annual plants and do not need to re-establish root systems each year.
The major problem is the lack of crop-specific data. There are so many environmental variables that it is hard to apply general characteristics to specific plants. More than anything else, this argues for USDA-conducted hemp research programs. A case on hemp, for or against, must be based on contemporary research data, and the case for hemp must be compared with the cases for other alternative crops.
The Congressional Office of Technology Assessment published a background paper in 1993 discussing the environmental concerns of energy-crop farming: “Energy crops with limited tillage and which return large quantities of organic matter (e.g., leaf litter) to the soil can improve soil quality compared with those that rely on frequent tillage or complete removal of crop residues. Such a protective layer of vegetative cover helps to provide shading, maintain soil moisture content, prevent erosion and may offer other environmental services.” Deep roots improve soil quality.
Water quality is affected by the levels of fertilizers used in agriculture to the extent there is seepage. The deep roots of hemp and other energy crops helps to prevent such runoff, and according to the OTA, “Energy crops may offer a tool not previously available to help deal with some of these water-quality issues,” including contamination, water-table changes and runoff.
Large environmental issues need to be faced. What will the transportation and processing of these raw materials produce in terms of air pollution? What will be the effect on wildlife habitats of converting tens of millions of acres of land to energy cropping? There are no easy answers, and advocates of biofuel must realize that complex, substantial problems remain to be solved.
Conclusion: Why Not Hemp?
The national biofuels program is a long-term effort that relies on extensive research and development. This effort represents a significant investment by the federal government in achieving its bioenergy objectives. Its purpose is to discover more about the energy capability of plants high in cellulose and seed oil. Hemp is rich in both.
You should ask your congressional representatives why the United States isn’t studying hemp for this purpose. Do not accept excuses that this or that other crop produces more fiber, better oil or more biomass. The USDA is studying dozens of plants, many with overlapping potentials. If they deserve study, why not hemp? Do not accept excuses that the plant lacks modern economic value, for technological developments are providing many old products with new value. Again, why not hemp?
Cannabis provides just as much usable cellulose and seed oil as many other plants being developed as energy crops, but uniquely produces two energy-source materials from a single plant. There are plants that produce more biomass or more seed oil than cannabis, but how many can provide both at once, in one plant?
Hemp for fuel: pipe dream or economic reality? That’s up to you. Do your congressional representatives even know we have a national biofuels program? If not, show them this article and put them on the spot: Why not hemp?
For More Information:
Robbelen, G., et al. (eds.): Oil Crops of the World (McGraw Hill, New York, 1989).
US Congress, Office of Technology Assessment: Agricultural Commodities as Industrial Raw Materials (Government Printing Office, Washington, 1991).
US Congress, Office of Technology Assessment: Potential Environmental Impacts of Bioenergy Crop Production (Government Printing Office, Washington, 1991).
US Department of Agriculture: New Crops, New Uses, New Markets, the 1992 Yearbook of Agriculture. (Government Printing Office, Washington, 1992).
Government Printing Office: (202) 783-3238.
Copyright © 1995, High Times. All rights reserved.