August 12, 2010
A Biofuels Primer
Over the last several years increasing attention as well as increasing controversy has focused on the topic of biofuels. Most specifically the issues surrounding biofuel relate to how much their use reduces CO2 and other greenhouse gasses as well as how the use of certain basic materials to produce these biofuels (particularly corn) impacts the availability - and thus the cost - of these commodities for other uses, namely for human consumption.
Let's take a look at the most popular biofuel feedstocks, how they stack up against one another from an environmental impact perspective as well as how they compare with one another with respect to the other principal uses each feedstock has and how this might impact human and/or animal populations.
Biofuels – In the broadest sense biofuel is defined as any fuel derived from biomass or living/recently living plant material. They may offer some of the most promising alternatives in our efforts to decrease dependence on traditional fossil fuel sources (oil, gas, petrol, coal, etc).
Biofuels offer the only immediate alternative to fossil fuels and they also have the potential to help limit the environmental impact from fuel emissions. In addition, they are the only direct substitute for oil in transport that is available on a significant scale in most countries.
The concept of using biofuels is not new, the inventor of the combustion engine, Nicholas Otto, conceived his invention to run on ethanol. Rudolf Diesel’s first engine was designed to run on peanut oil while early versions of the Ford Model T ran on ethanol.
Plant biofuel, has become one of the most promising forms of renewable energy available today. This is particularly important when comparing biofuel to other technologies, such as hydrogen, which also have potential, because these other potential fuels are still quite far from large-scale viability –particularly because they will require major changes to vehicle fleets and the fuel distribution infrastructure.
Additionally, the abundance of raw materials and ease of use with existing equipment and infrastructure means that biofuels are one of our most promising petro-fuel alternatives for reducing greenhouse gas emissions as well as for diversification of the energy supply in the immediate future.
The key reasons why biofuels are appealing on a global scale include:
• They are immediately available
• Their use can help provide energy security and diversity
• Biofuel production will give new opportunities for farmers and developing countries
• They have the potential to reduce greenhouse gas emissions
Principal Forms of Biofuel:
Ethanol is a liquid alcohol made of oxygen, hydrogen and carbon and is obtained from the fermentation of sugar or converted starch contained in grains and other agricultural or agri-forest feedstocks.
Starches (corn, grains, potatoes), sugars (sugar cane, sugar beet), biomass
The USA is the world’s largest producer, having produced 34.2 billion liters in 2008. Brazil is the number 2 global producer of ethanol, producing 24.7 billion liters in the same year. The EU produced approximately 2.7 billion liters in 2008, followed by China which produced 1.9 billion liters.
Ethanol is primarily blended with petrol (gasoline) to use as transport fuel.
Biodiesel is a non-toxic, biodegradable fuel. The majority of biodiesel is from oily feedstocks in a process called transesterification, where the oil is reacted with an alcohol (usually methanol) and a catalyst (such as sodium hydroxide).
Vegetable oils (canola, corn, cottonseed, palm, soy, sunflower) animal tallow, recycled greases
Annual production worldwide:
3.8 billion liters in 2005
In 2006, Germany produced approximately 2 billion liters, followed by France at 557 million liters and the United States at 284 million liters.
Biodiesel is mainly used as a replacement for diesel or in a blend with traditional diesel fuel. It is used primarily as a transport fuel, but can replace diesel in any engine.
Biogas consists mostly of a gas called methane which is the principal chemical present in “natural gas”. Bacteria produce methane as they break down cellulosic (plant based) material, whether in a swamp or bog, or in an industrial biogas generator - a reactor that allows the collection of biogas for power generation. Another type of biogas is carbon monoxide rich gas made via thermal gasification.
Landfill gas, sewage sludge gas, corn silage, liquid manure, cereals
Annual production worldwide:
402,602 TJ (terajoule)
The United States produces approximately 160,000 TJ; the UK and China each produce approximately 58,000 TJ, and produces Germany approximately 42,000 TJ annually.
Biogas can be used in the same motors that use natural gas. Currently only a very small proportion of biogas production is used in transport. Currently, the majority of biogas is used in the production of electricity and heating.
The global food crisis saw maize and wheat prices double during the period 2003-2008. Due to the rising use of biofuels during this period, particularly ethanol derived from corn, many people identified the use of biofuel as the principal reason for this increase, however research has shown that while biofuel production has - and likely will continue to have an impact on the cost of food for human consumption, the actual cost increases that can be directly attributed to the use of biofuel remains difficult to accurately identify.
Furthermore, as biofuel production technology improves and especially as we move towards using second generation biofuels that do not require food otherwise earmarked for the human food chain, this issue though important is not as significant as some parties would have you believe.
In the above mentioned price increases, for example, biofuel production was simply one component contributing to food price inflation. The recent drought in Australia, floods elsewhere in the world and other adverse weather conditions have had a negative effect on harvests leading to food shortages and consequently price increases.
Further as we experience an evermore rapidly changing global climate weather is becoming even more unpredictable and severe resulting in a continuing rise in food prices as crop yields - particularly in developing nations are reduced and in some cases where entire crops may fail due to changing environmental conditions.
In addition, rapid population growth has placed a higher demand on food and this factor alone has played a significant role in food price increases.
In fact, far from being the bane of global food production, biotechnology can cost-effectively optimize the yields of both crops for food and fuel. Ultimately, biotechnological innovations related to agriculture will provide more affordable food and fuel.
nd this, second generation biofuels are made from non-food feedstocks. By focusing on second generation crops, feedstock options are widened and a greater amount of fuel is available for the market, with the added benefit of potential for green house emission savings.
Sources: Joachim Von Braun and R.K. Pachauri, “The Promises and Challenges of Biofuels for the Poor in Developing Countries”, IFPRI 2005-2006 Annual Report Essay (Washington, D.C.: International Food and Policy Research Institute), November 2006.
Other than plant biotechnology, a number of other factors will prevent fuel from being produced at the expense of food. In many cases, a plant can produce both commodities – first the food can be processed, and the remaining plant material is used to produce fuel.
For example, bagasse is the biomass remaining after sugarcanes are crushed to extract the sugar. Bagasse is a feedstock for sugarcane-based ethanol.
Furthermore, many of the most suitable biofuel crops are not usually used as food. Sweet sorghum, jatropha, switch grass, types of wood and other non-edible plants are all ideally suited for the production of fuel.
Finally, it is likely that second-generation biofuels feedstocks will be available within 5 to 10 years. These second-generation feedstocks are typically non-food plants, such as switchgrass, and will not affect the food supply.
Second Generation Biofuels
As you have likely gleaned from the information presented above, first generation biofuels have some significant limitations that severely impact their overall prospects as truly viable sources to replace petro-fuels.
Among these the two principal issues are the fact that these Gen-1 biofuels rely on feedstock that is otherwise used for human and animal food consumption.
This fact alone places very real limits on just how much material is available for biofuel production. Put simply, past a certain point the cost to create these fuels has a direct impact on the cost of food.
Secondly the energy required to produce these fuels as well as their limited ability to actually reduce the production of greenhouse gasses calls into question their long term viability.
Beyond this, scientists familiar with this field have raised concerns about clearing land upon which existing but non-useful material (such as old growth forests) lie.
The concern is that by clearing land to plant more generation one biofuel crops we are actually removing one of the most important and effective means of capturing CO2 and replacing it with material that ultimately will contribute to creating more of these same gasses that are the source of a significant percentage of the global warming problem we are trying to resolve.
Second generation biofuels have been designed with these problems in mind. The goal is to extend the amount of biofuel that can be produced sustainably by using biomass consisting of the residual non-food parts of current crops, including material left behind once the food crop itself has been extracted.
This includes stems, leaves and husks as well as fruit skins, pulp, etc. Other candidates for second generation biofuel feedstocks include crops that are not used for food purposes including switch grass, and jatropha as well as industrial waste like wood chips.
Here are the critical chemical details that differentiate second generation biofuels from those tested for the first generation of these new energy sources:
All plants contain cellulose and lignin. These are complex carbohydrates (molecules based on sugar). Lignocellulosic ethanol is made by freeing the sugar molecules from cellulose using enzymes, steam heating, or other pre-treatments.
By fermenting these sugars, ethanol can be produced in the same way as first generation bioethanol production. The by-product of this process is lignin. Lignin can be burned as a carbon neutral fuel to produce heat and power for the processing plant and possibly for surrounding homes and businesses.
Lignocellulosic ethanol has the potential to reduce greenhouse gas emissions by around 90% when compared with fossil petroleum.
At present, IOGEN Corporation has developed a demonstration scale lignocellulosic ethanol production plant in Canada. Currently this facility produces around 700,000 liters of bioethanol each year. They are currently working to build a full scale version of this operation.
A large number of other lignocellulosic ethanol plants have been proposed in North America and around the world.
Another method to create fuel from biomass is the Fischer-Tropsch process. This process uses biomass to create a gas which is subsequently converted to a liquid fuel. When biomass is the source of the gas production the process is also referred to as Biomass-To-Liquids (BTL).
Third Generation Biofuels
Although still in development, (and with no current commercial scale production available) third generation biofuels appear to be very promising. Typically, third generation biofuels are derived from various species of algae.
Algae offers three crucial benefits over traditional terrestrial feedstocks such as corn, soybean, palm oil and others. First and foremost is the advantage in land-use. The energy density of algae is vastly superior to other crops; even at the low end of the potential oil-by-volume estimates.
While the advantage conferred by using algae as a feedstock varies depending on the strain of algae, what is confirmed is that certain kinds of algae have been observed to achieve photosynthetic efficiencies of up to three times that of corn and almost four times that of switchgrass.
Currently a couple dozen firms are active in this space, however - as stated above, none of them has started production at commercial scale. Nevertheless, it looks as though it is finally gaining some momentum and entering a high growth phase.
In fact, despite the economic downturn, venture capital firms poured $176 million into algae startups in 2008, including a record $84 million of it in Q4. Several firms have also taken the route of entering into joint-venture agreements with larger oil and gas companies or utilities.
While this particular petro-fuel replacement is still in its infancy, it bears watching as the benefits - much greater energy density, byproducts that themselves are highly useful (such as nutrients and substrate for pharmaceutical manufacture), the potential to scrub CO2 while the feedstocks themselves are cultivated, the ability to grow these feedstocks much more rapidly than conventional sources and finally the fact that their production does not require additional deforestation makes this sector one of the hottest in the sustainability race.
Fourth Generation Biofuels
When considering fourth generation biofuels the key word to remember is “bioengineered”. This is because the advances that will make fourth generation biofuels superior to previous generations are being done at the genetic level in the feedstock sources being used.
Basically, scientists are developing genetically engineered plants that have the ability to sequester far more CO2 than non-GMO feedstocks. So far eucalyptus and dahurian larch have been genetically modified for this purpose.
In fourth generation production systems, biomass crops are seen as efficient 'carbon capturing' machines that take CO2 out of the atmosphere and lock it up in their branches, trunks and leaves. The carbon-rich biomass is then converted into fuel and gases by means of second generation techniques.
Then, before, during or after the bioconversion process, the carbon dioxide is captured by utilizing so-called pre-combustion, oxyfuel or post-combustion processes. The greenhouse gas is then geosequestered - stored in depleted oil and gas fields, in unmineable coal seams or in saline aquifers, where it stays locked up for hundreds, possibly thousands of years. (what we’ll do with this sequestered CO2 down the road is a question I’ve yet to see convincingly answered).
The resulting fuels and gases are not only renewable, they are also effectively carbon-negative. Only the utilization of biomass allows for the conception of carbon-negative energy; all other renewables (wind, solar, etc) are all carbon-neutral at best, carbon-positive in practice. Fourth generation biofuels instead take historic CO2 emissions out of the atmosphere.
Unfortunately, Gen-4 biofuels are still some way off. Furthermore, like any other solution that relies upon genetic engineering, this technology has its detractors. There are a large number of people concerned about the impact that genetically modified plants - and particularly those that might be distributed on a large scale can have.
As any molecular geneticist is quick to point out, we are only just beginning to unlock the secrets of true bioengineering and as with any nascent scientific area there are likely to be unforeseen consequences (both good and bad) as we progress with this line of research.
at does seem clear about fourth generation biofuels is that once we truly get the science fully developed, these fuels with their double-duty feedstocks would appear to pave the way to not only truly sustainable production of post-petroleum fuels but also a means to scrub some of the excess CO2 out of our environment in a truly cost efficient and sustainable way.
Wrapping it Up
Although this is an unusually long post, we have actually barely scratched the surface of this highly complex and rapidly developing sector.
As you can clearly see a lot of money and a large number of very bright people are working hard to make sustainable liquid fuel sources a reality in the near future.
It is also plain to see that the solutions developed so far each present their own set of challenges with no one solution coming out on top as the clear winner in the race for a sustainably produced petro-fuel alternative.
That said there is a vast amount of money on the line for companies that do manage to successfully address these issues and create an environmentally beneficial product that doesn’t require deforestation, does not cause a reduction in available human foodstuffs and which can compete and win economically when compared to conventional fuels.
While necessity may be the mother of invention, it is the opportunity for enormous financial windfalls that drives the entrepreneurial process.
Very few areas possess the potential for a windfall anywhere near that of the energy sector. In the final analysis, it is this fact that gives me the greatest optimism for these technologies.
While we may actually be depending upon these solutions to continue life as we know it, I still find it comforting to know that the same motivations that have lead to breakthroughs in so many areas are driving research in this critically important area full speed ahead.
TrackBack URL for this entry:
Listed below are links to weblogs that reference A Biofuels Primer: