CORSIA: The first internationally adopted approach to calculate life-cycle GHG emissions for aviation fuels

The aviation sector has grown at a significant pace in recent years, and despite improvements in aircraft efficiency, the sector's impact on climate change is a growing concern. To address this concern, the International Civil Aviation Organization (ICAO) established the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) to help reduce aviation greenhouse gas (GHG) emissions. This paper presents a methodology agreed by the 193 ICAO member states to evaluate the life-cycle GHG emissions of sustainable aviation fuels (SAFs), in the CORSIA system. The core life-cycle assessment and induced land use change values of SAFs are presented to determine the GHG savings of certified pathways. The paper aims to present that a number of SAFs can yield significant life-cycle emission reductions compared to petroleum-derived jet fuel. This implies the potentially major role of SAFs in reducing aviation's carbon footprint

Investment in Cellulosic Biofuel Refineries: Do Waivable Biofuel Mandates Matter?

We develop a conceptual model to study the impact of mandate policies on stimulating investment in cellulosic biofuel refineries. In a two-period framework, we compare the first-period investment level (FIL) under three scenarios: laissez-faire, non-waivable mandate (NWM) policy, and waivable mandate (WM) policy. Results show that when plant-level marginal costs are increasing then both NWM policy and WM policy may stimulate FIL. The WM policy has a smaller impact than does the NWM policy. When the plant-level marginal costs are constants, however, WM policy does not increase FIL but does increase the expected profit of more efficient investors

The impact of considering land intensification and updated data on biofuels land use change and emissions estimates

BackgroundThe GTAP model has been used to estimate biofuel policy induced land use changes and consequent GHG emissions for more than a decade. This paper reviews the history of the model and database modifications and improvements that have occurred over that period. In particular, the paper covers in greater detail the move from the 2004 to the 2011 database, and the inclusion of cropland intensification in the modeling structure.ResultsThe results show that all the changes in the global economy and agricultural sectors cause biofuels induced land use changes and associated emissions can be quite different using the 2011 database versus 2004. The results also demonstrate the importance of including land intensification in the analysis. The previous versions of GTAP and other similar models assumed that changes in harvested area equal changes in cropland area. However, FAO data demonstrate that it is not correct for several important world regions. The model now includes land intensification, and the resulting land use changes and emission values are lower as would be expected.ConclusionsDedicated energy crops are not similar to the first generation feedstocks in the sense that they do not generate the level of market-mediated responses which we have seen in the first-generation feedstocks. The major market-mediated responses are reduced consumption, crop switching, changes in trade, changes in intensification, and forest or pasture conversion. These largely do not apply to dedicated energy corps. The land use emissions for cellulosic feedstocks depend on what we assume in the emissions factor model regarding soil carbon gained or lost in converting land to these feedstocks. We examined this important point for producing bio-gasoline from miscanthus. Much of the literature suggests miscanthus actually sequesters carbon, if grown on the existing active cropland or degraded land. We provide some illustrative estimates for possible assumptions. Finally, it is important to note the importance of the new results for the regulatory process. The current California Air Resources Board carbon scores for corn ethanol and soy biodiesel are 19.8 and 29.1, respectively (done with a model version that includes irrigation). The new model and database carbon scores are 12 and 18, respectively, for corn ethanol and soy biodiesel. Thus, the current estimates values are substantially less than the values currently being used for regulatory purposes

A comparison between GTAP-BIO and GLOBIOM for estimating biofuels induced land use change emissions

In this study, we compare two of the most important models in the literature of estimating biofuels induced land use change (ILUC) emissions, GTAP-BIO and GLOBIOM. Since GTAP-BIO is publicly accessible while GLOBIOM currently is not, we use biofuel pathways from the results documented in the most recent GLOBIOM report and compare them using GTAP-BIO with the same specifications. Five EU biofuel pathways, including sugar beet ethanol, starchy crop ethanol, rapeseed oil biodiesel, soy oil biodiesel, and palm oil biodiesel, are tested. The results from GTAP-BIO show lower ILUC emissions for each of the five pathways. The gap in ILUC emission values between the two models is larger for vegetable oil biodiesel pathways than for sugar and starch ethanol pathways. Simulation results are compared to the extent GLOBIOM results were available in the documentation. The major drivers of differences in the two models are livestock rebound response, palm related issues (e.g., palm oil yield and peat oxidation factor), and foregone sequestration on abandoned land. The analysis shows that the strong livestock rebound effect, low palm oil yield, and high abandoned land foregone sequestration factor may lead to an overestimation of ILUC emissions in GLOBIOM

Technological progress in US crop production: Productivity gains, abundant supply of crop calories, evolution in the livestock industry and implications for biofuel production

This paper evaluates in a holistic way major trends in US production of food, feed, and biofuel commodities over the period 1961-2014. It is motivated by literature that examines parts of the changes but does not integrate them. We develop a comprehensive data set and then conduct analysis of the major trends that emerge. We identify eight major trends and then combine them to four major themes. The first theme is the huge gain in agricultural productivity over this period. An important component of this theme is that the productivity gain was sufficient to achieve substantial total production growth as agricultural land declined over the period. Second, there has been a major transformation of the livestock sector as less efficient and more expensive beef has been replaced by more efficient and less expensive poultry. As this change has happened, the livestock sector has become more land efficient, less land used in livestock. The third major change is that US calorie production is now substantially more than the needs for food and feed. Finally, the first three major themes have enabled the fourth, which is growth of US renewable fuel production, while agricultural land declined over time. Acknowledgement : No Acknowledgemen