The discourse has been heating up around biofuel for well over a year now. The classic food versus fuel debate has been engaged recently by the United Nations, while scientists, climate change experts, and farmers begin to question the scale and logistics of biofuel replacement of the current liquid fuel demand.

This June, one of us (Dr. Jason Bradford) interviewed Lawrence Berkeley National Laboratory staff scientist and Post Carbon Fellow David Fridley on the bi-weekly radio show the Reality Report. The topic for the interview: “The Myths of Biofuels” finds Bradford and Fridley engaged in a devastating analysis of the scale and logistics of replacing our current fossil fuel demand with ethanol and biodiesel. In short, a large scale industrial biofuel system will wreak havoc on the soil, require an entirely new distribution infrastructure (due to the corrosive nature of ethanol), not easily adapt to the current fleet of USA autos, will compete heavily with food production and natural ecosystems that are seen as potential cellulosic biofuel feedstocks, and will do little to actually replace the current (or future) energy demands of liquid fuel.

Two weeks later, the Reality Report picked up where the Fridley show left off and we both joined Yokayo Biofuels President, Kumar Plocher on the show. The question was: If biofuel is not going to be sustainable on a large industrial scale, then would a local biofuel system be an appropriate response to the limitations of long-distance transport and petrol dependent methods of cultivation and processing of biofuel? If biofuel is produced for local consumption how much land would be needed, what crops would be used, and how would they be processed? Again, simple math painted a picture of an inflated hope and hype. We ran the numbers and with the 35,000 acres (14,000 hectares) of remaining prime farm land in Mendocino County approximately 84,900 acres (34,000 ha) would be needed to replace current county diesel consumption if canola was used as the prime feedstock.

Additionally, approximately 231,100 acres (94,000 ha) of farm land would be needed to replace the current gasoline consumption with corn-based ethanol. It doesn’t really matter much which crops, or combination of crops, are considered--the land base isn’t available to support a biofuel industry even on a local scale that meets current fuel demand. These analyses also absurdly assume the use of all agricultural land for fuel production, leaving no room for food! This is unconscionable and not the direction that any serious farmer or environmentaly aware person desires to advocate.

As the hype around biofuel already begins to dissipate, serious researchers and planners are advocating curtailment of long distance transport and the adoption of electric vehicles as one of the most sustainable options to replace the work and carbon footprint of the internal combustion engines. Vegetable oils and ethanol are useful products and should not be omitted from agricultural production, but their uses require further consideration. Why do we have to burn these useful feedstocks when they have multiple alternate uses? Should biodiesel production be limited to the reuse of waste food oil?

In an article published by AlterNet, David Morris from the Institute of Local Self Reliance makes two important observations related to the uses of vegetable oils and plant-based sugars that are consistent with the position of the Local Energy Farm Program. Morris suggests that

“human nutrition is the highest use of plants, followed by medicinal uses and possibly clothing [and…] we should first use biomass to substitute for industrial products that use fossil fuels rather than for the fuels themselves. [W]hile there is insufficient biomass to displace a majority of fuels; there is a sufficient quantity to displace up to 100 percent of our petroleum and natural gas-derived chemicals and products. And these are much higher value products.”

Additionally, he recognizes that: Electricity, not biofuel, will be the primary energy source [note: we consider electricity an energy carrier, with wind, solar radiation, etc. being renewable sources] for an oil-free and sustainable transportation system. But biofuel can play an important role in this future as energy sources for backup engines that can significantly reduce battery costs and extend driving range.

While biofuel might remain a short-term transition technology, it is being recklessly advocated by the United States Senate as a panacea for the liquid fuel appetite. One response is to advocate appropriate uses of biofuel, including its role in agriculture. Another is to adapt to new information and seek alternate ways of powering crucial societal infrastructure. One such component is a relocalized agricultural system.

We should remember that biofuel was originally produced by farmers for on-farm use. Just because you can power an internal combustion engine on bio-blends does not necessarily mean that it is a suitable energy replacement or clear cut solution to salvage the industrial model which is so deeply dependent on cheap liquid petroleum.

Before agriculture began to juggle the burdens of constant soil degradation, increased mechanization, and cheap labor (see Steinbeck’s ‘Grapes of Wrath’), animals were used for the cultivation of crops. However, like a biodiesel tractor, some land must be dedicated to feeding a team of horses. On good pasture land it is estimated that 5 acres (2 ha) of land is needed per horse. Marginal land could require about 13 acres (5 ha) per horse, and possibly much more.

Similarly, to produce 1000 gallons (3,800 liters) of biodiesel requires the cultivation of 10.25 acres (4 ha) of canola. This is assuming you have access to processing equipment and methanol (which is normally derived from natural gas). Whether you consider horses, oxen or biofuel to reduce dependence of fossil fuels, cropland is used that will often compete with land needed to grow food.

For example, data from the Nebraska Tractor Test Laboratory shows that the performance of small, modern tractors at around 20 hp requires about 1.7 gallon (6.4 liters) of diesel fuel per hour of work. If we estimate that a tractor will be in use about 1000 hours per year, this would require 1700 gallons (6,400 l) of fuel. In biodiesel terms, it would take 17 acres (6.9 ha) of prime crop land to grow the fuel for one small tractor per year. Of course we should also think about how much land such a tractor could cover in a year. A small tractor could cultivate about 25 acres (10 ha) in those 1000 hours, meaning that after fuel crop use only 8 acres (3.2 ha) would remain for non-fuel crops.

Post Carbon Institute’s Energy Farm Program is addressing the tension between food vs. fuel, or land vs. energy. In our search for ways to reduce these tensions comes the latest Energy Farm Demonstration Project: The Electric Tractor.

We have made connections with activist and inventor Stephen Heckeroth and are seeking to test cutting edge agricultural equipment for a post-petroleum world. The electric tractor does not compete for food and prime agricultural land for fuel, has a significantly reduced carbon footprint, increases the scale of acreage that can be cultivated, and is easy to operate for the 50 Million New Farmers that Richard Heinberg is calling for in the coming century. Stephen is not the only person who has made the electric tractors. John Howe has been working on retrofits of agricultural equipment powered by electricity.

This week we took a (petroleum-powered) scenic drive through the redwoods to the Mendocino coast to visit Stephen Heckeroth and demo his “Solar Electric Tractor.” Stephen has been working on alternatives to fossil fuel use in both his private and professional life since 1970. His company, Homestead Enterprises, has been doing electric tractor conversions since 1993, and has become an internationally recognized consultant on industrial and agricultural electric equipment. In 1996-97, Ford-New Holland commissioned Homestead Enterprises to build an electric tractor prototype. In 1997-98, a Japanese company, Eifrig Ltd. Commissioned another prototype. A fully functional design was completed in July 1998 and several provisional patent applications were filed in August 1998.

As Stephen points out: Our future is only as sustainable as the tools we use to get there. The daily energy income from the sun is gigantic and it is feasible to use already existing renewable energy infrastructure to “re-fuel” the Electric Tractor. If the farm has yet to invest in renewable energy infrastructure, it is also possible to charge the batteries with standard 110V power (or 240 volts in other parts of the world).

Let’s run through some numbers to help us evaluate the land requirements of electric tractors versus tractors operating with biofuel. Electric motors are about 90% efficient at converting energy to work, and solar panels are the most efficient way of converting radiant sunlight energy into electricity (approaching 20% vs 1% or much less for plants). Stephen’s tractor can hold 5 kWh of battery packs that will give the same kind of performance in terms of work over a year as the 1700 gallons of diesel fuel in a small tractor. 5 kWh of batteries can be recharged each day with a 1 kW photovoltaic system covering about 40 sq ft (3.7 sq meters) of roof space. By contrast, 43,000 sq ft (4,000 sq m) are in an acre (which is 0.4 hectares).

In terms of fuel dollars, 1700 gallons of diesel cost about $5,100 in 2007. Installing a 1 kW photovoltaic system might cost about $10,000. By investing once in double the annual cost of fuel, a farmer could power a tractor for decades.

Not only does this appear to be an economically wise investment, but electric tractors are a pleasure to use. As you would expect from an electric motor there is no diesel exhaust emissions and no loud engine noise. While driving the tractor we could actually hear birds chirping (a rare experience when operating heavy machinery). With an electric tractor there is no longer a need for engine oil or oil filters, a radiator and coolant, no need for fuel filters, no engine overhauls, and it offers a lower operating cost ($0.50) to charge the 5kWh battery pack. There is a 1500W charger/inverter on the tractor and a complementary AC power outlet. This is a useful feature because it allows the use of electrical equipment in the field (e.g. sorghum press, or thresher and winnower). The ability to process certain crops in the field (like sorghum) is a good way to circumnavigate the need to transport large amounts of material to a central processing facility.

We plan to put the tractor through its paces and provide data that farmers will find useful as they begin to evaluate the efficacy of this exciting technology. Although in theory we should have great performance from an electric tractor, a lot of questions exist related to how long the tractor can work (similar to the range of an electric car) and whether or not the machine has enough power for the rigorous demands of cultivation. To test the machine we will attempt to run a dryland grain demonstration in Willits, CA. We intend to plant a fall crop of wheat or oats using a disk, harrow, and seeder. These classic implements used to be horse-drawn and do not require the intense energy that PTO (Power-Take-Off) implements require (less draw-down on the battery bank). The over-winter rains will help to get the crop established without relying on intensive irrigation and we plan to come back in the next summer to harvest and process the cereal crop. The experiment is two-fold in which we get a chance to demonstrate and produce grains with minimal amounts of fossil fuel and high energy inputs while also collecting data related to operation time and power capacity of the prototype electric tractor.

Aside from John Howe and Stephen Heckeroth, we have not heard of other people using electric tractors for other than mowing; we hope that many are out there. We would like to hear from you. We invite readers to check our numbers and the assumptions above and please tell us how realistic we are, based on your data, calculations and experience.

If you want to see Stephen’s tractor in operation, check out this link.

For more information about the Willits/Brookside Energy Farm and about the electric demonstration, please contact Dr. Jason Bradford or Christoffer Hansen.

For more information about the Energy Farms Program, please contact Julian Darley, President Post Carbon Institute (email or call 1 800 590 7745)

Electric Tractor Front View

Jason Testing The Front Suspension on a Hill

1500 Watt Charger/Inverter with Battery Bank (Mounted Over Rear Tires)

AC Power Outlet to Use Tools In the Field

Switchgrass: (Panicum virgatum) is a perennial grass native to North America. Because it is native, switchgrass is resistant to many pests and plant diseases as well as being very tolerant of poor soils, flooding and drought. It is easily germinated from seed, and capable of producing high yields with very low applications of fertilizer. Switchgrass makes for a great energy crop because it grows fast, capturing lots of solar energy and turning it into chemical energy which it stores as cellulose. Switchgrass reaches its full yield potential after the third year planted, producing approximately 6 to 8 tons per acre; that is 500 gallons of ethanol per acre. At maturity, widely spaced switchgrass plants can measure 20 inches in diameter at ground level. Switchgrass has a huge, permanent root system that penetrates over 10 feet into the soil, and weighs as much as the above-ground growth from one year. It also has many fine, temporary roots. All these roots improve the soil by adding organic matter, and by increasing soil water infiltration and nutrient-holding capacity.

Miscanthus: (Miscanthus x giganteus) is a tall perennial grass that has been evaluated in Europe during the past 5-10 years as a new bioenergy crop. Like other energy crops, the harvested stems of miscanthus may be used as fuel for production of heat and electric power, or for conversion to other useful products such as ethanol. Because the crop is a sterile hybrid it is established by planting pieces of the root, called rhizomes, which develop into the mature plant. Miscanthus is ready for harvest within 2 years and yields continue to improve until they level off around the 5th or 6th year. Speculating from European data, under typical agricultural practices over large areas, an average of about 3 tons per acre dry weight may be expected at harvest time.

Miscanthus exhibits:

1. Relatively high yields 8-15 t/ha (3-6 t/acre) dry weight.

2. Low moisture content (as little as 15-20%).

3. Annual harvests, providing a regular yearly income for the grower.

4. Relatively good energy balance and output/input ratio

5. Low mineral content, which improves fuel quality.

Jerusalem Artichoke: (Helianthus tuberosus L.) is an annual flowering plant native to North America. It grows 1-3 meters tall with flowers similar to the sunflower but much smaller (4-8cm in diameter). Jerusalem artichokes are grown throughout the temperate world for their tubers, which are used as a root vegetable. The tubers are gnarly and uneven, vaguely resembling ginger root, with a crisp texture when raw. Unlike most tubers, but characteristic of members of Asteraceae (Sunflower family to which it belongs), the tubers store the carbohydrate inulin instead of starch. The inulin is isolated on the basis of its high solubility in hot water; by boiling the tuber and allowing it to cool polysaccharides can be extracted. Yields tend to vary with soil conditions, cultivar and season, but fresh weights in excess of 100 tons per hectare have been recorded, which is around 8 tons per hectare of sugar. For this reason, Jerusalem artichoke tubers are an important source of energy.

Kenaf: (Hibiscus cannabinus) is considered one of the most promising alternatives to virgin, soft, and hard woods for paper production. An herbaceous annual related to cotton and okra, kenaf is a member of Malvaceae (Mallow family).

USDA chose kenaf from among five hundred candidates as the most promising non-wood fiber for pulp and paper production for several reason:

· Rapid growth: Kenaf reaches 12-18 feet in 150 days, while southern pine (A species commonly grown on tree plantations) must grow 14 to 17 years before it can be harvested.

· High yield: Kenaf yields 5-10 tons of dry fiber per acre, or approximately 3 to 5 times as much as southern pine.

· Exceptional papermaking characteristics: Less chemicals, heat and time are required to pulp kenaf fibers because they are not as tough as woodpulp and contain less lignin (an average kenaf plant contains only 9% lignin, while southern pine contains 29% lignin.

· Opportunities also exist for the production of renewable feedstock from Kenaf, as it is such a fast growing plant.

Sugar Beet: (Beta vulgaris L.), a member of the Chenopodiaceae family, is a biennial plant whose root contains a high concentration of sucrose, accounting for 30% of the world's sugar production. During its first growing season, it produces a large (1–2 kg) storage root whose dry mass is 15–20% sucrose by weight. Sugar beets have the potential to produce 30-40 tons of roots per hectare under non-irrigated conditions and 50-70 tons per hectare with irrigation. The research done by the Agronomic University of Bucharest in the South zone of Romania has recorded ethanol production at 5,508 liter ethanol per hectare. The sugar beet may become, in the future an important energy crop.

Soybean: (Glycine max) is an annual legume (Fabaceae). It may grow prostrate, not growing higher than 20 cm (7.8 inches), or stiffly erect up to 2 meters (6.5 feet) in height. Soybeans provide the principal oil being utilized for biodiesel in North America. To produce soybean oil, the soybeans are cracked, adjusted for moisture content, rolled into flakes and solvent-extracted with commercial hexane. According to the U.S. Department of Agriculture's (USDA) Farm Service Agency, one bushel of soybeans yields approximately 1.4 gallons of biodiesel. Soybeans contain about 20% oil, so it takes almost 7.3 pounds of soybean oil to produce a gallon of biodiesel. In addition soybeans enhance the nitrogen content of the soil and provide the soil with many nutrients.

Dale Sorghum: (Sorghum bicolor L.) is an annual tropical grass that is easily propagated from seed. A prolific producer, averaging about twelve feet in height at maturity; sorghum is a short rotation crop, meaning that it can be harvested multiple times throughout the year. Sweet sorghums have been selected for their high sugar content and are normally grown for molasses production. Dale Sorghum is a drought resistant variety of sweet sorghum that requires less intensive irrigation. It is an early maturing (115 day) variety with superior disease resistance to many older common varieties and is well adapted for syrup production, which can be converted to methane or ethanol. It produces on average 40 tons per hectare of cane, 25 tons per hectare of juice, and provides a grain yield of 2-6 tons per hectare. It is estimated that for each ton of cane yield 40 liters of ethanol can be produced, that is 1600 liters of ethanol per hectare of Sorghum.

Peredovik Sunflower: (Helianthus annuus) is an energy and protein rich annual that at maturity (12 weeks after germination), reaches a height of 4 feet. Second only to soybeans, sunflower oilseed varieties are the most important source of high-quality vegetable oil in the world. This Russian cultivar produces small, black seeds that yield more oil than most other sunflowers (approximately 952 liters of oil per hectare). While typical sunflower seeds contain 25–35% oil, the peredovik sunflower can contain up to 50% oil. According to the Duke handbook of Energy Crops, a hundred kilograms of dry seed will yield about 40 kilograms of oil, 15–20 kilograms of hulls, and 40 kilograms of proteinaceous meal.

Peredovik sunflowers provide stacked functions including:

1. Food in the form of filtered oil

2. Oil that can be converted to biodiesel

3. The remaining press cake from expelling can be fed to livestock

4. The flowers are bee forage

5. The dried stalk is a carbon component for compost

Flax: (Linum usitatissimum L.) is an erect annual with slender stems that is grown for its seed and fiber. It is not generally a crop that is spoken of in relation to alternative fuel sources; however, there are groups looking into the possibility of using the long tough stem fibers of oilseed flax as feedstock for large scale burners. Flax seeds contain 20–30% protein, and are the source of linseed oil. Flax straw has a per ton heating value similar to soft coal that is much greater than other crop residues. Not only is the straw cheaper than conventional fuels; it is also carbon neutral fuel; meaning that the plant takes carbon from the air during the growing season to produce the straw, reducing the amount of greenhouse gasses in the atmosphere. With seed yields of 1000–4000 kilograms per hectare, and reported oil content of 34–37%, flax has the potential to yield 1500 kilograms of oil per hectare.

Corn: (Zea mays L.), the single largest U.S. crop, is increasingly being used as a biomass fuel. It is currently harvested from 30 million hectares within the United States, which is almost ¼ of all the harvested cropland in the country. The average yield of moist corn grain is 8600 kilograms per hectare; that is approximately 150 bushels per acre. According to the National Corn Growers Association, 1.3 billion bushels of corn were allocated towards ethanol production in 2004. David Pimentel, a professor from Cornell estimates that one acre of U.S. corn can be processed into about 328 gallons of ethanol, but planting, growing and harvesting that much corn requires close to 140 gallons of fossil fuels and costs $347 per acre; that is $1.05 per gallon of ethanol before the corn even moves off the farm, meaning that 70% more energy is required to produce ethanol from corn than the energy that ethanol contains. No research has been done; however, as to whether corn may serve as a sustainable energy crop when grown organically and at a much smaller scale. Corn residues, including the stalk and cob may also prove useful in future energy production.

Energy Inputs to Corn Production

1. Nitrogen fertilizers (all fossil energy)

2. Phosphate, potash, and lime (mostly fossil energy)

3. Herbicides and insecticides (all fossil energy)

4. Fossil fuels: diesel, gasoline, liquified petroleum gas, and natural gas

5. Electricity (almost all fossil energy)

6. Transportation (all fossil energy)

7. Corn seeds and irrigation (mostly fossil energy)

8. Infrastructure (mostly fossil energy)

9. Labor (mostly fossil energy)

Buckwheat: (Fagopyrum esculentum) is a short season crop that does well on poor, sandy, somewhat acidic soils. Plants will begin blooming in about 40 days from seeding, with the first seeds mature after an additional 40 days. The seed is an achene, similar to a sunflower seed, with a hard outer shell and soft inner meat. Most of the buckwheat grain utilized as food for humans is marketed in the form of flour but whole grain may be used in poultry scratch feed mixtures as they are high in protein. As well as being a food crop, buckwheat is used for its biomass.

Comfrey: (Symphytum officinale L.) is a prolific perennial herb belonging to the Borage family (Boraginaceae) that has long been recognized by organic gardeners for its great usefulness and versatility, both medicinally and as a fertilizer. Because the majority of comfrey under cultivation is hybridized, it is typically propagated from root cuttings. It is a sturdy plant, reaching a height of 2 to 3 1/2 feet with very large, hairy lower leaves, as much as 15 to 20 inches long. Its roots draw nutrients from deep in the soil to produce the energy rich foliage that offers many methods of application as a fertilizer.

Comfrey offers many uses as a fertilizer:

1. Comfrey as a compost activator

2. Comfrey as liquid fertilizer

3. Comfrey as a mulch

4. Comfrey as a potting mixture ingredient

Quinoa: (Chenopodium quinoa) is grown primarily for its highly nutritious edible seeds, which are small yellow flattened spheres, approximately 1.5 to 2 millimeters in diameter; however, the leaves of the plant can also be eaten. The seed coat contains bitter saponin compounds that must be removed before human consumption, but it is this bitter pericarp that keeps the crop nearly untouched by birds. In addition to containing a balanced set of essential amino acids for humans, quinoa’s protein content (12%–18%) is very high, making it an unusually complete foodstuff; this means it takes less quinoa protein to meet one's needs than it does wheat protein. Quinoa is a good source of dietary fiber and phosphorous and is high in magnesium and iron; it is gluten free and considered easy to digest. There are about 1480 calories in one pound of quinoa flour or seeds (55.3% carbohydrates, 13.1% protein, 5.8% fat, 13.6% fiber, 9.3% water, and 2.9% minerals).

Amaranth: (Amaranthus sp.) with 60 recognized species, makes up its own family, Amaranthaceae. The herbaceous annual grows 5 to 7 feet, with broad leaves and a showy flower head of small, red or magenta, flowers. The seed heads resemble corn tassels, but are somewhat bushier, composed of tiny (1/32"), lens shaped seeds that are a golden, creamy, tan color. Amaranth resists heat and drought; it has no major disease problems, and is among the easiest of plants to grow. Each plant is capable of producing 40,000 to 60,000 seeds that like buckwheat and quinoa, contain protein that is unusually complete for plant sources. The leaves also are a very good source of vitamins including vitamin A, vitamin B6, vitamin C, riboflavin, and folate, and dietary minerals including calcium, iron, magnesium, phosphorus, potassium, zinc, copper, and manganese. Several studies have shown that like oats, amaranth seed or oil may benefit those with hypertension and cardiovascular disease.

Oats: (Avena sativa) are an annual grass that reach 1.3 meters in height. Producing an average of 125 bushels per acre, which is 8,000-12,000 pounds per acre of biomass, oats are primarily grown for livestock feed; in fact less than 5% of the total production in this country is for human consumption (mainly as oat flour). Oat is the only cereal containing a globulin or legume-like protein, avenalins, as its major (80%) storage protein. The protein content of the hull-less oat kernel, or groat, ranges from 12–24%, the highest among cereals. Oats help conserve soil, they require relatively less chemical fertilizers, pesticides and herbicides; they reduce water contamination by agricultural chemicals, and provide nutritional benefits to both humans and animals.