HEFA+ for Aviation
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WORKING PAPER 2018-06 Policy and Environmental Implications of Using HEFA+ for Aviation Authors: Nikita Pavlenko, Anastasia Kharina Date: March 21, 2018 Keywords: Green Diesel, HEFA+, Alternative Jet Fuels, AJF Introduction is a synthetic hydrocarbon typically impacts of aviation. We first evaluate made from bio-feedstocks such as the production of HEFA+ and the The aviation sector must confront vegetable oil or waste fats. HEFA+’s impact of feedstock choice on HEFA+’s rapidly increasing greenhouse gas primary competitive advantage stems sustainability and GHG performance. (GHG) emissions and ambitious decar- from its similarity to renewable diesel The next section analyzes the state of bonization targets. The International [also known as hydrogenated veg- HEFA+’s deployment and estimates Civil Aviation Organization (ICAO), the etable oil (HVO) or hydrogenation- the near-term availability of HEFA+. United Nations agency charged with derived renewable diesel (HDRD)], a The final section discusses the policy coordinating international standards biofuel already produced at commer- implications of expanding HEFA+ use for civil aviation, projects that the cial scale for the road sector. Existing in the aviation sector and competition greatest share of in-sector GHG reduc- production of renewable diesel for the for feedstocks with the road sector. tions from aviation will come from road sector dwarfs the scale of pro- transitioning away from petroleum- duction of other potential jet fuel sub- based jet fuel toward sustainable, low- stitutes; production could theoretically Production and Processing carbon alternative jet fuels (AJFs). The ramp up quickly at existing facilities. If HEFA+ production resembles the pro- AJFs that may replace petroleum in HEFA+ were to be certified as an AJF, duction of renewable diesel for the the future can vary widely in feed- it would therefore immediately have road sector, a process wherein veg- stocks used, cost, and environmental a market advantage relative to other etable oils, waste oils, and fats are pro- performance. These factors must all be AJFs that are further from commer- cessed into hydrocarbons. Renewable taken into consideration when devel- cialization. Proponents of HEFA+, such dieselis chemically different from tra- oping fuels policies for the aviation as Neste Corporation, tout the high ditional biodiesels produced for the sector if its carbon emissions are to be technological readiness and relatively road sector, which are produced via successfully reduced. low price of HEFA+ relative to other trans-esterification to generate fatty AJFs; this suggests that, once certi- acid methyl esters (FAME). FAME- To facilitate the transition to AJF, fied, substantial volumes of HEFA+ Boeing has begun testing the technical could be used in the aviation sector in based biodiesels may cause problems suitability of HEFA+ (Hydroprocessed the near term (Erämetsä, 2017). in some engines at high concentrations Esters and Fatty Acids+) on flights as and thus require blend limits in the road a petroleum jet fuel substitute. HEFA+, This study assesses the state of HEFA+ sector; they cannot be used in aviation commonly called “green diesel” or deployment within the aviation sector because of substantial chemical dif- high-freeze-point HEFA (HfP-HEFA), and its potential to reduce the climate ferences from petroleum-based jet Acknowledgements: We thank Dr. Michael Lakeman, Associate Technical Fellow on Biofuels Strategy at Boeing Commercial Airplanes, who graciously provided his time to discuss Boeing’s endeavor in testing and certifying HEFA+ as AJF. We also thank Dr. Stephanie Searle and Dr. Daniel Rutherford for their guidance and thorough review. This study was funded through the generous support of Environment and Climate Change Canada. © INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION, 2018 WWW.THEICCT.ORG POLICY AND ENVIRONMENTAL IMPLICATIONS OF USING HEFA+ FOR AVIATION fuel (Zeman, 2010). In contrast, the Food Crops: Waste Feedstocks: H2 renewable diesel production process Soybean Oil, Used Cooking Oil, Canola Oil, Animal Fats, converts bio-oils into a chemical form Palm Oil PFADs, Tall Oil more similar to fossil fuels, thus facil- itating higher blending with petro- leum-based diesel. The first step in Feedstock Feedstock Hydro- Production renewable diesel production (Figure Deoxygenation Production Pre-Treatment isomerization Separation 1) is bio-oil treatment with hydrogen gas and a catalyst in order to remove oxygen (i.e., hydrotreatment). Once H O, Acid GasGreen the oxygen is removed, the remaining 2 Diesel hydrocarbon chains are then hydroi- somerized to break down the long Hydroprocessing chains and improve the cold flow Light End properties of the finished fuel. The end product generally contains hydro- Figure 1. Flow diagram of renewable diesel production process. carbon lengths in the diesel range, Source: Derived from Honeywell UOP (n.d.) although further hydroisomerization (i.e., those with shorter carbon chains) of D7566 relative to traditional HEFA can break down the chains of carbon produced by the biorefinery, such (Starck et al., 2016). Therefore, HEFA+ even further, thereby increasing the as naphtha and propane (Landälv & testing has occurred at blend rates of share of bio-kerosene (Landälv & Waldheim, 2017; Starck et al., 2016). 15%—substantially less than the 50% Waldheim, 2017). These light compounds cannot be blends allowed for traditional HEFA HEFA+ production closely resembles included in finished jet or road fuel, fuel in road transport (Erämetsä, 2017; the AJF pathway for Hydroprocessed so reducing their share of the product Radich, 2015). Esters and Fatty Acids (HEFA). stream raises the overall value of fuel production by increasing the yield of Traditional HEFA fuel was already cer- Deployment tified by ASTM International in 2011, transport fuel relative to lower-value meeting ASTM’s Method D7566 , the materials. To produce HEFA+, manu- CERTIFICATION TIMELINE “Standard Specification for Aviation facturers can instead alter the HEFA Turbine Fuel Containing Synthesized process to reduce the intensity of the At the time of writing, HEFA+ is under- Hydrocarbons,” at blend levels of 50% hydroisomerization stage of hydro- going a rigorous research process to or below (Wang et al., 2016). A re- processing, leaving longer hydrocar- acquire the ASTM certification D4054 identification provision within ASTM bon chains more similar to diesel than “Standard Practice for Qualification D7566 states that AJF blends meeting to kerosene. and Approval of New Aviation Turbine all the requirements of D7566 also Fuels and Fuel Additives.” The mul- Decreasing the yields of light com- meet the requirement of ASTM D1655 tistage process involves aircraft and pounds reduces the cold flow prop- “Standard Specification for Aviation engine manufacturers and requires Turbine Fuels” and can be regarded as erties of the finished fuel relative to up to 890,000 liters of blended jet conventional fuels (ASTM International, traditional HEFA. The reduced cold- fuel to complete (Rumizen, 2013). The 2016; IATA, 2012). Therefore, at the weather performance for HEFA+ is certification process can be lengthy, as blend levels specified in a given fuel’s likely not a factor in most on-road it requires consensus from all original D7566 Annex, that fuel is considered a uses but takes on greater importance equipment manufacturers (OEMs) that “drop-in” AJF. in aviation, where jet fuel specifica- produce airframes or engines before tions for Jet A and Jet A-1 require a moving to the next stage of approval Producing traditional HEFA fuels maximum freezing point of –40°C (M. Lakeman, personal communica- requires additional hydroisomeriza- and –47°C, respectively (Starck et al., tion, January 24, 2018). As part of tion beyond that needed to produce 2016). The unblended or “neat” HEFA+ data collection, Boeing, in collabo- renewable diesel, as kerosene has a has a higher freezing point than tra- ration with the U.S. Federal Aviation shorter chain length than diesel. As ditional HEFA fuels, thus requiring a Administration (FAA) and engine the chains shorten, the process also greater share of petroleum-derived manufacturers, has conducted flight creates low-value light compounds fuel in order to meet the specifications tests onboard its ecoDemonstrator 2 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION WORKING PAPER 2018-06 POLICY AND ENVIRONMENTAL IMPLICATIONS OF USING HEFA+ FOR AVIATION 787 flight test airplane, using a blend 500 million liters of capacity under carcass and has lower value than meat; of 15% green diesel and 85% petro- construction (Wang et al., 2016). a farmer will thus decide whether to leum jet fuel in one engine (Boeing, Canada imports its renewable diesel, increase or decrease livestock produc- 2014). The final blending allowance for with zero domestic capacity in 2016 tion based on the price of beef rather HEFA+ in the ASTM standard is to be (Dessureault, 2016). Existing renewable than the price of tallow, which has a determined through further testing. diesel production in North America smaller impact on profits. We may would displace only 2% of U.S. and expect the supply of tallow to increase If approved, HEFA+ would be included Canadian jet fuel demand (approxi- if total beef production increases, but as an annex of ASTM D7566. Once the mately 72 million liters in 2017) (BTS, it will not change as a result of biofuel certification process is complete, the 2018; U.S. EIA, 2018). policies. Figure 2 shows