- Solar energy / Photosynthesis
- Foodstock fields
- Tractor trailer
- Ethanol biorefinery aka "Cellulosic Ethanol Plants" (located in close proximity to foodstock fields)
- Railroad / Tractor trailer
- Wholesale terminals (fuel blending and storage)
- Tanker trucks
- Retail fueling outlets
Biofuels are a class of liquid fuels derived from renewable, usually plant-based feedstocks. They are a renewable source of energy unlike traditional fossil fuels derived from petroleum, like diesel and gasoline. Ethanol 1 is a type of biofuel made by fermenting sugars from sugar cane, corn, or a variety of other feedstocks. Biodiesel is made from the esterification of feedstocks including oils from vegetable or animal fat oils. Feedstocks are the raw matter used as the baseline carbon source. Feedstocks for biofuels can include many different materials including what are considered "first generation fuels" based on easy-to-process starch-based plant matter, such as corn or sugar. Some ethanol or biodiesel can be generated from woody, cellulosic plant matter such as from the stalks and leaves. Non-food feedstock sources are typically considered "second generation" feedstocks.
Cellulosic ethanol is considered a class of advanced biofuel according to Renewable Fuel Standard (RFS2) mandate, a section of the Energy Security and Independence Act of 2007 - which set the first mandates for alternative fuel use in the US. . The term "advanced biofuel" is sometimes defined as any biofuel derived from non-corn based feedstocks. However, advanced biofuels are defined more narrowly by the RFS2 as any biofuel that reduces lifecycle GreenHouse Gas(GHG) emissions by 50% compared to baseline gasoline lifecycle GHG emissions.
by the year 2022, the fuel industry must blend a minimum of 36 billion gallons of renewable fuels into its transportation fuels (gasoline or diesel, as appropriate). However, a maximum of 15 billion gallons of those 36 billion gallons renewable fuels are allowed to be corn starch-derived 8 ethanol (Schnepf & Yacobucci, 2013).
According to Bob Dinneen from the Renewable Fuels Association, of the total corn crop in 2012, about 40% of the corn produced in the US is used for ethanol and 35% is used for livestock feed. About 33% of the ethanol portion produces "distiller's dry grain" which is a high protein, high quality by-product that is also used as livestock feed. This results in approximately 48% of the total corn crop able to be still used as livestock feed.
The ethanol supply chain starts with the feedstock growing in the field, and follows ethanol through processing, distribution and use in a vehicle.
- The feedstock or crop is grown in the field. a. Corn ethanol is mostly grown in the Midwest of the US and is considered a first generation biofuel crop. Other common feedstocks are sugar cane in Brazil. b. Second generation or "advanced" feedstocks: Ethanol and Biodiesel producers are moving to other non-food feedstocks, considered second generation, such as jatropha, camelina, switchgrass etc. Cellulosic ethanol is slowly coming on line and uses woody plant mass, residual crop waste (corn cobs, stalks etc) to process into ethanol reducing impact on food stocks. c. There are various inputs with environmental considerations for a life cycle analysis at this stage such as pesticides, herbicides, fertilizers, water for irrigation if necessary, labor, machinery required for harvesting.
- It gets harvested and transported (typically by truck given the distributed nature of farm fields) to a nearby processing plant.
- Ethanol is pretreated, processed and distilled from the grain (using either wet or dry milling process) a. Distillers grain can be up to 70% of the resulting products which can be used as high protein feed for livestock, the rest is ethanol. (Depends on using wet or dry mill process- wet produces more, but consumes more energy) b. Typically there is some kind of enzyme or chemical requirement to break down starches or in the case of cellulosic ethanol-lignose.
- Ethanol gets transported (via truck or train or barge) to blenders
- Blenders mix ethanol with gasoline at requisite levels (See Policy Chapter RFS2)
- Blended Fuel is transported to gas stations (points of sale) and stored in tanks.
- Fuel is pumped into consumer's vehicle and combusted resulting in emissions.
The movement of the feedstocks and ethanol through the US must consider things like the bulky inefficiency of transporting unprocessed grains and having to be blended with conventional gasoline. The following chapter analyzes some of the complications with today's transportation fuel infrastructure impinging on the success and the environmental impact of ethanol.
4.3.1 Transport Grain Phase: From Field to Ethanol Plant
Part of the challenge with increasing ethanol use in the US is in part due to the flow of ethanol as it travels in the opposite direction of gasoline. The fields of corn grown for use in ethanol are mostly located in the Midwest. The harvested feedstock must be transported to an ethanol processing facility (biorefinery) which, given the bulky nature of the feedstock in order to be more economically viable are located close to the harvest site. "...ethanol is generally produced in the Midwest and needs to be shipped to the coasts, flowing roughly in the opposite direction of petroleum-based fuels. The location of renewable fuel production plants (such as bio-refineries) is often dictated by the need to be close to the source of the raw materials and not by proximity to centers of fuel demand or existing petroleum pipelines." (GAO, 2011)
In contrast, ethanol is produced mostly in six states in the Midwest. The feedstock is gathered from farmers across these states, processed at a nearby ethanol plant, sent to a blending terminal (see Figure 10 below) to be blended with gasoline, and then distributed to the point of sale (US Department of Energy, 2010).
In order to move ethanol from distiller to blender, it is currently extremely difficult and expensive to use pipelines, which is how a lot of gasoline is moved. Gasoline, like ethanol, also uses a combination of train, boat, barge, and trucks, but also can leverage the use of pipeline which dramatically lowers its transportation costs and reduces its lifecycle GHG emissions. Because of ethanol's corrosive properties and hydrophilic nature, it results in compatibility issues with the pipeline itself and other components like seals etc., and typically requires either upgrades, severe cleaning of existing infrastructure or its own dedicated fleets for transportation or dispensing. Once ethanol has been blended with gasoline at levels less than ten percent, with respect to its corrosive nature it can then generally use existing infrastructure, however the challenge still remains that if water comes in contact with ethanol, it can pull the ethanol out of suspension. So even with El0, it remains difficult to avoid encountering water during the transport phase particularly via pipeline. In the case of gasoline, water and gasoline are relatively easy to separate and can be stored and allowed to settle and the water can be removed from the bottom (petroleum is lighter than water). With ethanol-gasoline blend, water brings the ethanol out of suspension, and what remains are two liquid combustibles, neither of which meet standards that can be sold. Both need to return to a refiner to be re-blended.
4.4 RINs
RIN stands for Renewable Identification Number, it is a sort of serial number for biofuel. A RIN is "a unique 38-character number that is issued (in accordance with EPA guidelines) by the biofuel producer or importer at the point of biofuel production or the port of importation. Each qualifying gallon of renewable fuel has its own unique RIN." (Schnepf & Yacobucci, 2012) RINs are generated as a part of the production process by ethanol producers. This means that there is no "currency" regulator like the federal reserve who can print money, there is only the EPA who enforces the minimum quantity of biofuels produced or blended by refineries and ensures that there is no counterfeiting or other types of RFS2 violations.
Because there are four different types of biofuels that are mandated and tracked by the EPA, RIN credits must provide a way to track the biofuel producer and the type of biofuel. This helps the EPA study the effects of the mandates and ensure that the required amount of biofuels are blended into the requisite amount of fossil fuel. Parties that are obligated to adhere to the mandates include refiners, blenders, and those who import gasoline and diesel fuels. These obligated parties are required to purchase and blend a certain amount of biofuels per gasoline sold or produced.
"The obligated party establishes its "Renewable Volume Obligation" by taking the RFS percentage (7.76% in 2008) and multiplying that number times the total volume of gasoline produced or imported. The obligated party then submits its pro-rata share of gallon-RINs to EPA in order to demonstrate compliance with its portion of the RFS.
The RIN, in essence, is now a credit used as a method to keep score. If an obligated party blends more renewable fuel than its share, it generates excess RINs. These excess RINs can then be traded or sold to another company that finds it more economical to purchase RINs instead of blending ethanol or biodiesel. Banking and trading of RINs as renewable fuel credits forms the basis for an open RIN market" (McMartin)
RINs can be bought and sold independent of the batch of biofuel that was produced once the renewable fuel has been blended into the gasoline or diesel 26 . This can create a separate market for these credits and help blenders and fuel producers buy or sell RINs during years when renewable fuels may be difficult to obtain.
Capital Requirements are the amount of fixed costs needed to start an ethanol plant and get it running. The capital costs ethanol has sustained over the last decade are substantial. On the other hand capital costs for gasoline refining and distribution are considered "sunk 33 " since the petroleum industry is much older. However the petroleum industry still faces substantial costs for continuing exploration and technology development for tight gas and unconventional oil extraction (shale gas, etc). As the ethanol industry matures, capital investment costs have plateaued but there are still substantial development costs needed for cellulosic processing plants to come online and for ethanol to achieve lower costs than gasoline. Capital costs still need investments in the 5 basic areas of the ethanol supply chain: sufficient growth of feedstocks, feedstock transport, more and improved ethanol plants- with the development of cellulosic ethanol plants specifically, increasing capacity on railways, and the ethanol dispensing infrastructure. One study performed by the National Renewable Energy Laboratory (NREL) completed a study comparing the amount of capital costs required to achieve varying amounts of cellulosic ethanol by 2017 (Sandor, Wallace, & Peterson, 2008). Their baseline model to achieve 500 million gallons per year estimated would require a combined $4.3 billion investment from private capital funding, along with $24.7 billion in government spending for a total of $29 billion. To achieve higher quantities of cellulosic ethanol it would require higher levels of capital investment. At the highest output rate they studied, 7.2 billion gallons of cellulosic ethanol, the study estimated that there needed to be a combined $27 billion dollars of private investment along with $24.4 billion in government spending for a total of $51.4 billion.
One estimate from the RFA puts the next generation (cellulosic) of ethanol plants, at approximately five times the cost of "grain-based facilities". (Dinneen, 2010) The ethanol industry requested loan guarantees up to $250 million representing 90% of the cost of a cellulosic plant.
"Drop-in Renewable Diesel" made via hydroprocessing results in a fuel identical to petroleum diesel.
Biobutanol is a cellulosic biofuel that can be blended with other fuels for use in conventional gasoline vehicles and is considered a drop-in fuel. Biobutanol can be used as an oxygenate and blended with gasoline in concentrations up to 11.5 percent by volume.
Small-scale pilot plants, which produce less than 10 mgy of fuel, have been able to produce cellulosic ethanol, but problems exist with the current technologies that need to be overcome before commercial-scale (producing more than 10 mgy) cellulosic ethanol production becomes viable. Due to these remaining technology challenges, there are not yet any commercial cellulosic ethanol plants operating in the United States.
Most ethanol plants are located in the Midwest where feedstocks for ethanol are grown. However, the biggest markets for ethanol are on the East Coast, California, and Texas, where large refining centers are located and where fuel consumption is the highest. Ethanol producers must transport their product long distances to the refining centers in these areas. Rail or tanker trucks transport the majority of ethanol. The remainder is transported by barge. Prior to shipment from the ethanol plant, 100 percent ethanol is blended with 2 percent petroleum, rendering it unfit for human consumption. This process is called denaturing and is performed in order to avoid liquor tax implications outlined by the Alcohol and Tobacco Tax & Trade Bureau (TTB). Denaturing creates 98 percent ethanol or E98. All ethanol transported from the ethanol facility is E98.
To break down biomass, ZeaChem uses a natural bacterium, acetogen, found in termites, cockroaches and other organisms. The bacterium ferments cellulose into acetic acid, which is made into ethanol. No carbon dioxide, a greenhouse gas, is produced in the fermentation.
ZeaChem CEO Jim Imbler is confident his "simple, proven technology" will produce ethanol in a low-cost, sustainable manner. Having a supply of local plant material is a competitive edge, he said, and believes with the ready supply of forest trimmings and agricultural residue, Oregon could support half a dozen cellulosic ethanol refineries, a boon for hard-hit rural areas.
ZeaChem built the plant in Oregon to demonstrate its core technology platform at scale. ZeaChem opened the plant as a technology institute to third parties, which has created two profoundly beneficial outcomes. First, the third parties who come and work at the demo plant are able to dramatically accelerate the scale up of their own technology at a fraction of the cost to building and owning a plant of their own. Second, it has created foundational relationships for mutually beneficial project development activities at its 1st Commercial plant in Boardman and around the world.
http://www.zeachem.com/technology-institute/
Red Rock Biofuels LLC (“RRB”) is developing refineries in the U.S. to convert woody biomass to renewable drop-in jet, diesel and naphtha fuels. Each refinery will utilize 175,000 dry tons of woody biomass feedstock to produce 16 million gallons per year of finished products.
Velocys has one of the largest dedicated Fischer-Tropsch (FT) teams in the industry. The FT process lies at the heart of both gas-to-liquids (GTL) and biomass-to-liquids (BTL). In the FT process, synthesis gas (syngas), consisting of a mixture of carbon monoxide and hydrogen, is converted into paraffinic hydrocarbons over a cobalt or iron catalyst.
Smaller scale GTL turns natural gas (or biomass) into premium liquid products, such as diesel and jet fuel, adding value to shale gas and making stranded or flared gas economic – untapped markets of up to 25 million barrels per day.
Velocys technology, protected by over 900 patents, is specifically designed for smaller scales, resulting in standardized modular plants that are economic, easier to ship and faster to install, at lower risk, even in the most remote locations.
Whole Energy NW Industrial PDX
http://www.biofuelsdigest.com/bdigest/
In general, fuels produced by the biomass-to-liquids process can deliver up to 90% lifecycle GHG emissions reduction compared to their petroleum-based equivalents. The US Environmental Protection Agency recently confirmed that a portion of the products produced at ENVIA’s Oklahoma City project will be eligible for cellulosic diesel (D-code 7) or cellulosic biofuel (D-code 3) renewable identification number (RIN) credits for advanced biofuel.
https://en.wikipedia.org/wiki/Second-generation_biofuels
https://en.wikipedia.org/wiki/Biomass_to_liquid
http://www.diva-portal.org/smash/get/diva2:649618/FULLTEXT01.pdf
https://www.princeton.edu/pei/energy/publications/texts/Kreutz-et-al-PCC-2008-10-7-08.pdf
Among BTL options the production of Fischer-Tropsch liquids (FTL) from biomass has been given considerable attention [4,5,6,7,8]. FTL offers as advantages over cellulosic ethanol the prospects that: (i) no significant transportation fuel infrastructure changes would be required for widespread use, (ii) the technology could plausibly come into widespread use more quickly than cellulosic ethanol, which needs considerably more development before it can be widely deployed, (iii) it can probably accommodate more easily the wide range of biomass feedstocks that are likely to characterize the lignocellulosic biomass supply—because gasification-based processes tend to more tolerant of feedstock heterogeneity than biochemical processes.