Where will Biofuels and Biomass Feedstocks Come from?
By Vinod Khosla
When it comes to biofuels we have a few choices and options – we can do it poorly, with short-
run approaches with no potential to scale, poor trajectory, and adverse environmental impact, or we can do it right – with sustainable, long-term solutions that can meet our biofuel needs and our environmental needs. We do need strong regulation to ensure land use abuses do not happen. A recent report published by the Royal Society highlights some of the factors that need to be balanced – they note that some changes in land use (such as clearing tropical forest or adapting peatlands for crop cultivation) can do more harm than good. To counter these potential abuses, we have suggested each cellulosic facility be individually certified with a LEEDS (international certification program for “Leadership in Energy and Environmental Design”, a green building rating system) like “CLAW” rating and countries that allow environmentally sensitive lands to be encroached be disqualified from these CLAW rated fuel markets. We think a good fuel has to meet the CLAW requirements:
C – CARBON emissions
L – low to no additional LAND use; benefits for using degraded land to restore biodiversity and organic material
A – AIR quality improvements- i.e., low carbon emissions
W – limited WATER use.
Cellulosic ethanol (and cellulosic biofuels at large) can meet these requirements. The Royal Society notes that the uncertainty of some biofuels do not obscure the main benefits of cellulosic fuels: “(1) biofuels from cereals, straw, beet and rapeseed are likely to reduce GHG emissions, though the estimated contribution varies over a wide range, from 10 to 80% (averaging about 50%) depending on crop, cropping practice and processing technologies; (2) biofuels from lignocellulose material are likely to show a twofold or more improvement in average abatement 1potential when compared with biofuels derived from food crops.” Our research and data
suggests that cellulosic ethanol can reduce emissions on a per-mile driven basis by 75-85%, with limited water usage for process and feedstock as illustrated later. Range, Coskata and other companies currently have small scale pilots projecting 75% less water use than corn ethanol, and energy in/out ratio between 7-10 (Energy returned on energy invested or EROI, even though we consider this a less important variable than carbon emissions per mile driven). The question that eventually comes to the forefront is land use and biomass production – how much will we need?
What will it take? Is it scalable enough to make a meaningful positive impact? To be conservative, we assume CAFE standards in the US per current law though we expect by 2030 to have much higher CAFE and fleet standards (hopefully up near 54 miles per gallon (mpg) or 100% higher than 2007 averages), thus dramatically reducing the need for fuel and hence biomass. For, this to happen, we need a combination of factors, including lighter vehicles, more efficient engines, better aerodynamics, low cost hybrids and whatever else we can get the consumer to buy that increases mpg.
What do we believe? As we will cover in this paper, we believe that given reasonable assumptions on technologies, biofuel yields, and adoption of better agronomic practices, most of our biofuel needs can be met with fairly limited land usage. From a technology perspective, the advances and continuing research into thermochemical processes offers potential far exceeding that of standard biochemical approaches. From an agronomic perspective, a greater
understanding about the benefits of crop rotations and conservation practices combined with an ability to use generally underutilized land offers us the ability to vastly increase our biofuel producing abilities without cultivating additional land. In particular, we think the potential for winter cover crops as a biofuel source has been greatly understated, and that even modest yield assumptions would allow them to meet a significant portion of our biofuel needs. In the long run, the combination of these multiple factors (an example of the innovation ecosystem at play) will allow us to sever our dependence on oil – for good. Hybrid vehicle technologies will help but not
materially on a worldwide basis at current costs.
A note about evaluating alternatives – when looking at a potential solution, it‟s important not to
evaluate a technology/approach in isolation; rather, we ought to compare it relative to other viable approaches to determine its actual feasibility. For example, every nuclear plant that we did not build over the last 50 years (due to environmental concerns) was almost certainly replaced by a coal plant, whose environmental footprint was significantly worse. We are in danger of doing it again, by going after pie-in the sky or uneconomic solutions to replace oil. That could lead to even more problems - the alternative (as a long run transportation fuel solution) may well be oil shales (Canada is moving aggressively in this direction), which are even worse environmentally. Letting the perfect be the enemy of the good is irrational – marginal analysis counts.
Part I: What are the sources for biomass and biofuels?
There are many approaches to production of feedstocks for biofuels. To make a material impact in replacing gasoline, major feedstocks need to collectively produce more than a hundred billion gallons annually in the US and preferably more than 150 billion gallons to replace gasoline. Replacing gasoline and replacing diesel involve different technologies and markets. The focus here is principally on gasoline replacement in America‟s cars and light trucks though we do
briefly touch upon diesel feedstocks.
We believe that a sustainable biofuel needs yields of at least 2,000 gallons (ethanol equivalent) per acre (hopefully 3,000!) in the long run to meet the worlds oil replacement needs on a manageable amount of land (with the exception of winter cover crops that use no additional lands). We believe, as estimated in our papers elsewhere, that 2,500 gallons of ethanol equivalent per acre annually is a reasonable assumption. (Assuming corn grain yields of 140 to 170 bushels/acre that are typical of the mid-Western corn belt today, and 2.8 gallons of ethanol from a bushel of corn, the range in ethanol production from corn is only 392 to 476 gallons/acre.) Chemical and water inputs and the effect on biodiversity should be minimal, if any. Cost should be below that of oil. Feedstock production should not materially increase the land under annual cultivation nor affect food security materially but should enhance energy security, reduce poverty and increase rural incomes. None of the “food/feed crop” based biofuels (corn or sugar
based) or classic biodiesel sources (vegetable oils) comes close to these targets. Is such a fantasy possible? Yes! Part I covers sources of biomass, Part II will cover agronomy practices for yield, biodiversity, water and chemical efficiency, and Part III discusses the rationale of yield assumptions that lead to 2,500 gallons per acre. Our calculations later show that if we can increase engine and automobile efficiency significantly at the same time, we will need no additional land for biofuels.
Currently there are two primary feedstocks for the production of renewable biofuels to replace gasoline (almost entirely ethanol) to replace gasoline – sugar from sugar cane (primarily used in
Brazil) and starch from corn (the source of most US-based ethanol). In Asia and Africa, tapioca,
potatoes and other starch crops are being used (sadly!). Amongst feedstocks, there has been significant discussion regarding both corn stalks and wheat straw. We are not huge fans of wheat straw or corn stalks, though they are possibilities. In our opinion, cellulosic ethanol plants need to reach production levels of 100m gallons per year per plant to achieve economies of scale (expensive fuels don't sell! A local conversion plant near the field and distributed supply would be ideal and we continue to investigate technologies that might make this possible). That would dictate feedstock needs of around 1,000,000 tons - per year, per plant In the short and medium term, at biomass yields of 10 tons/acre (by 2030 we expect about 20-25 tons/acre), 100,000 acres of land would be needed per cellulosic ethanol plant or 40,000 acres by 2030. With yields of approximately 2 tons/acre, the usage of either corn stalk or wheat straw would effectively quintuple land usage and substantially increase transportation distances and costs, hence our skepticism. In addition, there is value to plowing corn stalks and wheat straw under to minimize
the need for commercial fertilizer. Winter cover crops like legumes and winter rye (no biomass optimized winter cover crops have been developed but grasses are a good candidate), grown on row crop lands during their idle period during winters, can yield 3-5 tons/acre with no additional land usage and may actually improve land ecology where row crops are grown anyway. In conjunction with winter cover crops, annual crop residue may become a viable supplement to winter cover crops annual/biomass yields per acre. To quote Prof Bransby, a renowned
agronomist from Auburn University in a personal communication:
“Regarding water and fertilizer needs of cover crops: The answer is that no irrigation is needed, and fertilizer needs are about
30% of the fertilizer requirements of corn. Also, there are multiple benefits from cover crop/traditional crop rotations (compared
to traditional crops with no cover crops), including better soil protection/less soil erosion, improved soil organic matter, better
water holding capacity, suppression of crop pests, etc. Provided this is done with conservation tillage practices, there should be
no serious negative environmental impacts.” He states further: “It is reasonable to assume that winter cover crops can be grown on the same land that our summer traditional crops are grown, and summer cover crops can be grown on land where traditional winter crops (mainly winter wheat) are grown. As far as I know, most of this land is currently idle/fallow at the time when these
cover crops would be grown. From the USDA National Agricultural Statistics website the 2007 acreage (in millions) for our major traditional crops is as follows: corn, 93; soybeans, 63; cotton, 11; sorghum, 8; winter wheat, 44; Total = 219. At a modest
estimate of 3 tons/acre/year, this would provide 657 million tons of biomass annually. With research and genetic improvement, I
believe the yield could be increased to 5 tons/acre within 10 years, for a total of 1.1 billion tons/year. Acreage for all annual crops
is 317 million. For various reasons, it is unrealistic to assume that 100% of land in traditional crops could be planted to cover
crops to produce biomass. Maybe 70%?”
While cover crops have been utilized historically for the agronomic benefits (more on the benefits of crop rotations later), increased biomass yield has not always been a primary area of focus. While many traditional cover crops such as legumes (clovers, vetches, medics, field peas) offer limited potential for biomass yields, other cover crops like small grains (winter rye, wheat, oats, triticale) offer substantial potential – we‟re confident that they can achieve the 3-4.6 ton
yields that we project, and perhaps even go further. Currently, these crops (and rye in particular) 2achieve yields of up to 4-5 tons per acre. These crops today are generally managed for forage or
grain - managing for forage is perhaps closest to managing for total biomass, but there are still differences in practices that offer potential for substantial yield improvements, along with plant breeding and many of the improved agronomic practices (we discuss these later in the paper). Our research leads us to be optimistic about this area, and we believe further investigation is called for.
In our most likely scenario, we have chosen to use 50% of the annual acreage of traditional annual crops for winter cover crops and about 70% of forest waste in our estimates. Each of these sources offers benefits. The DOE noted that major primary sources for forest biomass would be logging residues and fuel treatments, and that much of the forest material we project to
use “has been identified by the Forest Service as needing to be removed to improve forest health 3and to reduce fire hazard risks.” With regards to winter crops, our estimates suggest that any
feedstock transportation beyond about 50-75 miles (preferably under 30 miles) will reduce its competitiveness, unless the crop is very low cost (like winter cover crops), in which case a maximum 100 mile radius might make sense. Energy crops and winter cover crops will reduce the need of substantial transport infrastructure for biomass and answer critics‟ questions about infrastructure. If these plants were distributed around the country it would substantially reduced need for infrastructure. Smaller pipelines will be needed if most of the biofuels are not concentrated in the Midwest. Biomass crops will be widely distributed and will minimize the need for this infrastructure.
What are the price points needed for biomass to be profitable for farmers? Professor David Bransby notes that his communication with farmers suggests $60 per ton for switchgrass and similar crops would be reasonable, with the breakeven price decreasing as yields increase. Based on a switchgrass price model developed at the University of Auburn, the graph below highlights (one set of estimates) farmers‟ breakeven points for given yields and prices. Its worth
nothing that even at a $50 per ton price point, yields of as low as 7-8 tons/acre (which we are exceeding now) would allow farmers to be profitable.
What is the competitiveness of biomass vis a vis a oil? Since an air dry ton of biomass contains about 2.5 times the energy content of a barrel of oil (14.5 million btu vs. 5.8 million btu), $50/barrel oil could theoretically be competitive with $125/ton biomass. However, given the high cost and nascent nature of biomass processing, we believe a more conservative estimate is needed initially – as biomass processing costs decrease, we will see increases in the price of biomass (towards the 2.5 times oil price point) for farmers even as it remains competitive with oil. Today, we think a competitive feedstock cost based on current conversion efficiencies (which are subject to improvement), delivered to the factory, has to be below $50/ton of dry
biomass (plus or minus 25% depending upon feedstock type) to compete with $50/barrel oil (which we are unlikely to see again without significant reduction in demand).
As per the pricing constraints above, we limit (in our estimates) potential incremental land using feedstocks to crops that yield over 10 tons/acre in the mid-term – effectively, “energy crops”. 4The Royal Society‟s “Sustainable Biofuels” report notes the following:
“a significant advantage of developing and using dedicated crops and trees for biofuels is
that the plans can be bred for purpose. This could involve development of higher carbon
to nitrogen ratios, higher yields of biomass or oil, cell wall lignocellulose characteristics
that make the feedstock more amenable for processing ... Several technologies are
available to improve these traits, including traditional plant breeding, genomic
approaches to screening natural variation and the use of genetic modification to produce
transgenic plants. Research may also open up new sources of feedstocks from, for
example, novel non-food oil crops, the use of organisms taken from the marine
environment, or the direct production of hydrocarbons from plants or microbial systems.”
We should also note that a number of “biomass densification” technologies are being
investigated that may ultimately reduce biomass transportation costs even further but are currently in early research stages. For example, one approach is the production of “bio-oil” at
small-scale localized biomass pyrolysis units. This bio-oil can then be transported to a centralized facility for conversion and up-grading to ”biocrude” that can go into an existing
refinery or used as-is for applications like home heating oil (Kior).
5Source: David Bransby & Ceres .
As discussed earlier, we estimate feedstock costs need to be under $50 per ton delivered within the next decade (and lower in the short run) to compete with $50/barrel oil. Switchgrass and miscanthus-like grasses (C4 photosynthetic grasses) and certain trees are the most likely feedstocks to provide our liquid fuel requirements in the long run. Tree crops developed for the paper pulp business will also make for good sources of biomass. Many client paper mills have recently gone out of business and these communities are crying for local economic stimulus and
jobs. Given these prices, biomass has the potential to substantially increase farm income and reduce the need for farm subsidies.
The DOE Billion-Ton report confirms many of our conjectures. It notes: “It is assumed that
significant amounts of land could shift to the production of perennial corps if a large market for bioenergy and biobased products emerges.” It further notes that studies have shown that “if a farmgate price of about $40 per dry ton were offered to the farmers, perennial grass crops producing an average of 4.2 dry tons per acre (a level attainable today) would be competitive 6with current crops on about 42 million acres of cropland and CRP land.” We do note that this
report was published in 2005, and fuel and fertilizer costs have increased rapidly since then –
updated research is needed. We also believe yields of 2-6 times these estimates are feasible by 2030.
While we believe that energy crops will meet most of our feedstock needs, we have invested our time and money in the potential of waste feedstocks as we think they can make a material impact and reduce the above cited biomass needs by an additional 10-20% or more! Promising waste feedstocks include municipal sewage even municipal solid waste - the paper, wood, construction waste, even lawn clippings that are brought to a landfill. Something that has been a problem (especially with disposal) may soon become an opportunity! There is sufficient municipal waste to produce tens of billions of gallons of ethanol. The waste is available in large enough quantities (in most major cities) to justify waste-specific plants and actually has a negative cost (usually a tipping fee). We‟re also intrigued by the possibility of using farm organic waste One of our
favorites is a proposal to take all the waste carbon monoxide from steel mill flue gases (already collected and piped, available to go into a process!) to make ethanol. There is enough carbon 7monoxide coming out of today‟s steel mills to produce over fifty billion gallons of ethanol!.
Forest waste could be treated similarly and is discussed below.
Now to the numbers. How much biomass can we get to convert to biofuels without subsuming other uses for land and biomass? More than enough! There are four principal sources of biomass and biofuels we consider (1) energy crops on agricultural land and timberlands using crop rotation schemes that improve traditional row crop agriculture AND recover previously degraded lands (2) winter cover crops grown on current annual crop lands using the land during the winter season (or summer, in the case of winter wheat) when it is generally dormant (while improving land ecology) (3) excess non-merchantable forest material that is currently unused (about 226 million tons according to the US Department of Energy), and (4) organic municipal waste, industrial waste and municipal sewage.
For the US, the world‟s most oil intensive economy, our calculations show that a small dose of vision, two decades of agricultural development, and process technology that is in pilots today, with less than 5% of our annual crop and timberlands could more than supply our biofuels needs to replace most of our light-vehicle gasoline usage by 2030. The table below shows one of many possible scenarios – in the scenario below, we assume about 50% of the total annual crop acreage (317M acres) is used with winter cover crops; approximately 70% of excess forest waste identified by the DOE is used, and assume that waste-based (municipal organic waste, sewage,
steel mill flue gases, industrial waste, etc) ethanol accounts for 10% of total demand by 2030 –
resulting in dedicated energy crop usage of approximately 15M acres (The assumptions are
covered in Appendix A).
Scenario 1Acres Acres Biomass needed at Acres needed at KV Cellulosic Waste Winter needed 50% of needed at 75% of Ethanol Ethanol Ethanol Total Winter Cover Forest Forest from Expected projected projected projected Production Production Yield Biomass Cover CropCrop Excess Biomass dedicated Yield yieldEstimates Estimates(Gals/Ton)Needed AcresYield BiomassYield cropland (Tons/ac)yieldyield
(Tons - (Tons - (Tons - (Gallons - (Gallons - (Tons - (Acres (Tons - (Tons - (Tons - Billions)Billions)Millions)- Millions)Millions)millions)millions)millions)millions)millions)(best tech)(tons/ac)(tons/ac)
How Do We Get There?
2030 - How Much Land Do We Need?
Winter Forest Dedicated Total =Cover Excess Crop Land:BiomassCrops: Waste:24 t/ac18 t/ac12 t/acDisplaced Land -
Due to Dedicated 2015:=Energy Crops 14M tons21M tons14M tons13.618.227.349M tonsReclaimed Land -
based on 2008 corn
ethanol production, =assuming 70% land 2020:recovery163M tons68M tons19M tons-15.5-15.5-15.5251M tons
Net Land Use
(Excluding Winter =Cover Crops, Forest -1.9M 2.7M 11.8M 2025:Excess Waste)acresacresacres599M tons126M tons0M tons724M tons
2030:=735M tons158M tons334M tons1227M tons
While our projections above are based on our most likely scenario, other scenarios are possible. We project a range of scenarios using 50% or 70% of our annual crop lands for winter cover crops, using 50%, 70%, 100% of sustainable, harvestable forest waste, energy crop yields 12,18,24 tons/acre with and without usage of waste like municipal sewage and organic waste, and yields of 110 and 130 gallons ethanol equivalent fuel per dry ton. Early experimental data have shown that other biofuels may produce yields equivalent to 150 gallons of ethanol equivalent biofuels per ton (as opposed to the 110 projected in the table above), long before 2030; (based on data disclosed confidentially to us). In this (optimistic) scenario, ALL of our light-vehicle transportation needs would be met without using any additional devoted energy cropland! Going further, the USDA projects corn ethanol production of 9.3 billion gallons in 2008 – at 2.8
gallons per bushel and 150 bushels per acre, that suggests that 22M acres of corn crop is being devoted to corn ethanol today – 70% of this land could be “released” and reused for other
purposes (we assume that all ethanol production by 2030 will be cellulosic). We have outlined six potential scenarios in Appendix A (a summary is provided here – scenario 1 is highlighted
Scenario Waste Resources Winter Cover Winter Cover Excess Forest Biofuel Dedicated Land Use Net Land Use @
(% of total ethanol Crop - % of Crop Yield Biomass Yields @ 24/18/12 24/18/12 tons/ acre
demand in 2030) annual crop (Tons Per (Millions of (Gallons tons/acre (Millions of
land/ acres Acre) Dry Tons) per Ton) (Millions of Acres) Acres)
1: 10%– 15B gallons 50% – 159M 3-4.6 70% -158Mt 90-110 13.6 / 18.2 / 27.3 -1.9 / 2.7 / 11.8
2: - 50% – 159M 3-4.6 50% -113Mt 90-110 21.0 / 28.1 / 42.1 5.5 /12.6 /26.6
3: - 50% – 159M 3-4.6 50% -113Mt 90-130 12.5/16.6/25.0 -3.0 / 1.1 / 9.5
4: - 50% – 159M 3-4.6 70% -158Mt 90-130 10.6/14.2/21.3 -4.9 / 1.3 / 5.8
5: - 50% – 159M 3-4.6 100% -226Mt 90-130 7.9/10.5/15.7 -7.6 / -5.0 / 0.2
6: 10% –15B gallons 70% – 221M 3-4.6 100% -226Mt 90-130 0 -15.5
We should also note the point about water usage – cellulosic ethanol has come under attack
recently for excessive water usage, again without doing an apples-to-apples comparison with 8gasoline. Producing one gallon of gasoline uses 2-2.5 gallons of water; producing one gallon of
cellulosic ethanol (through the Range/Coskata processes) uses 1 gallon on water. Even account for the mileage discount of ethanol vs. gasoline (which we expect to decrease from 25% in 2020 to about 15% by 2030), the water usage of cellulosic ethanol is significantly lower than that of gasoline on a per mile driven basis! We assume that energy crops will grown as rainfed
Take Scenario 1: the key assumption here is recovering 3 tons/acre of biomass additionally per year from winter cover crops (growing to 4.6 tons/acre, or just over a 1.5% a year productivity increase). For conservation, we have not separately provided for summer annual crop biomass
residue. Using crop residue plus winter crops will provide for higher yields and allow substantial biomass to be plowed back into the soil for sustainability. Based on point data reports on energy crop yields and detailed in part III, we assume that 24 tons/acre of energy crop yields can be achieved by 2030, starting at 7 tons/acre in 2008.. However, the net land use requirements are immaterially affected if yields are assumed to be 25% or 50% lower, since winter cover crops provide the bulk of the biomass. It should be noted that the 3 tons/acre of biomass from winter cover crops could be made up of actual winter cover crop yields and use of parts of the biomass (corn stover, wheat straw, etc) from annual food crop cultivation. And that‟s only the beginning – one of our investments is working to improve the mileage efficiency of the standard ICE (Internal Combustion Engine) by 50-100% for ethanol and gasoline dramatically reducing biomass needs! Increased CAFE standards will help too. Additional degraded land can be recovered if our 10 year by 10 year biomass crop rotation scheme is followed (described in Part II), though we have not modeled this. In combination with the other factors listed above, we are confident that our biomass needs will not be a limiting factor by 2030. Furthermore, they will neither encroach on land needed for food production, nor cause destruction of tropical rain forests that are vitally important resources for carbon sequestration and control of green house gases.
While gasoline is the primary focus of much of this research, a diesel replacement is also a vital goal. Today, an alternative fuel like “classic” biodiesel (diesel produced mostly from vegetable oil) can meet some needs, but its inability to scale and its vegetable oil source will prevent it
it lacks trajectory. And from being a relevant scale replacement for petrodiesel in the long run –
it creates a food versus fuel controversy. We are very negative on classic biodiesel (see our Biodiesel paper). The primary feedstocks for classic biodiesel are vegetable oils such as rape seed, soybean and palm oil, with sources such as jatropha being used in India and other parts of the world. Unfortunately, none of these sources has high enough yields per acre - soybean oil yield is around 40-50 gal/acre, rape seed around 110-130, and jatropha at 170-180, while palm 9oil reaches as 630-650 gal/acre. Jatropha does have the benefit of growing on non-food crop
lands, limiting any food vs. fuel conflicts. Because food grains are well-optimized crops (with the exception of jatropha and algae), we don‟t expect vegetable oil yields to increase significantly over time (a 2X is projected for corn by 2015). As mentioned earlier, we believe that a sustainable biofuel needs yields of at least 2,000 gallons per acre (hopefully 3,000!) in the long run to produce the worlds oil replacement needs on a manageable amount of land. Unfortunately, none of the classic biodiesel sources comes close to these targets.
A source that can achieve these minimum yields is algae, which has not been optimized. However, there are many challenges for producing diesel from algae. Growth can be in open ponds or in enclosed bioreactors. Open ponds are the simpler, more economic approach. Enclosed bioreactors can be used to achieve higher yields but with increased capital and operating costs and we are skeptical about their economics. Methods such as the tools of synthetic biology can be used to improve the productivity of algae; however, these genetically engineered organisms are going to be controversial in open oceans. Hence we are cautious about investing in bioengineered algae. Our preferred source to replace petrodiesel is to use cellulosic biomass based “cellulosic diesel”. Companies such as our investments in Amyris, LS9, Kior, and
others believe they can produce diesel and jet fuel replacement at substantially lower costs than
food oil based diesel (below $1.75 per gallon) while getting all the high yield benefits of cellulosic biomass sources. At 2,500 gallons per acre and approximately 40 billion gallons of 10diesel usage (for on-road transportation), we will need roughly an additional 16M acres to meet
our transportation diesel needs in the US.
It is worth noting that unless we dramatically reduce carbon emissions and stop global warming, millions of acres of land will be “dislocated” from its current uses and must be figured into the “net land use” equation. Though many technologies will contribute to displacing oil based fuels, we don't believe any other technologies are pragmatically likely to achieve as large a reduction in emissions from transportation fuels as cellulose-based processes. A recent Booz Allen Hamilton study noted that worldwide, there is up an additional 6 billion acres of rain-fed land that is available for agricultural production (clearly, there would be opportunity cost associated with this land use). Farmers will make more money, we will sell less subsidized crops ( an issue over which the Doha round of trade talks have broken down as developing countries demand fewer agricultural subsidies in the west. Organizations like Oxfam now oppose the dumping of subsidized US food crop in Africa, where agriculture is often the only means of income generation). We will import less oil and export fewer crops allowing farmers in poor countries to make a living (helping reduce third world poverty) while we in the US improve our trade balance.
Part II: Better Agronomy for Energy Crops
We believe improved crop practices are a vital aspect in meeting our cellulosic feedstock needs. There are a few areas that offer significant potential – (i) crop rotation, (ii) the usage of
polyculture plantations, (iii) perennials as energy crops, and (iv) better agronomic practices. We address all four issues here. Though none of these have been extensively studied, early studies and knowledgeable speculation point to their likely utility. Further study of these techniques is urgently needed; especially the use of grasses or other biomass optimized winter cover crops.
(i) We have proposed the usage of a 10 year x 10 year energy and row crop rotation. As row crops are grown in the usual corn/soy rotation, lands lose topsoil and get degraded, need increased fertilizer and water inputs and decline in biodiversity. By growing no-till, deep rooted perennial energy crops (like miscanthus or switchgrass - see below) for ten years following a ten year row crop (i.e. - corn/soy) cycle, the carbon content of the soil and its biodiversity can be improved and the needs for inputs decreased. The land can then be returned to row crop cultivation after ten years of no-till energy crops. Currently unusable degraded lands may even be reclaimed for agriculture using these techniques over a few decades. A University of North 11Dakota study highlights some of the benefits for food crops. We expect similar or even greater benefits for food crop/energy crop long cycle (ten year) rotations, especially in soil carbon content: (1) Improved yields –a crop grown in rotation with other crops will show significantly
higher yields than a crop grown continuously. (2) Disease control– changing environmental
conditions (by changing crops) changes the effect of various diseases that may set in with an individual crop, and crop rotation can limit (and often eliminate) diseases that affect a specific crop. (3) Carbon content - Energy crops in the rotation can increase soil carbon content and reduce the impact of top soil loss materially. (4).Better land: the study notes farmers practicing crop rotations comment on improvements in soil stability and friability. In addition, crop rotations have the potential to increase the efficiency of water usage (by rotation deep-rooted and more moderately-rooted crops or rotation of perennials in long cycles with row crops)
One manifestation of the crop rotation approach is the idea of utilizing cover crops – crops such
as grasses, legumes, or small grains that are grown between regular crop production periods (i.e.