**2. Necessity for bio-jet fuel**

Recent fuel consumption survey shows that 12% of transportation fuel is accounted for by aviation industry and it contributes 2% of greenhouse gas to environment pollution and global warming. To comply with 2015 Paris Climate Change Accord, improved energy efficiency and increased low-carbon bio-energy and fuel utilization (rate) in aviation industries are expected, and such efforts are in progress in various related fields. As examples of such efforts, airlines and aircraft manufacturers voluntarily set goals for carbon-neutral growth, and 50% reduction of greenhouse gases by 2050 with respect to 2005 criteria and various concrete ways are implemented. Ordinarily, electricity, solar energy, and hydrogen fuel are mentioned as means of low-carbon energy utilization in transportation fields [3]. As for aviation industries, the only technically viable means is limited to bio-jet fuel and its utilization. Therefore, long-term carbon reduction is only made possible by increased utilization of bio-jet fuel. **Figure 3** shows IRENA's future prospect for carbon emission by aviation industries. As shown in **Figure 3**, it was known that the 1.5% reduction of greenhouse gas is reportedly possible by both the utilization of bio-jet fuel and the increase in the energy efficiency resulting from aircraft design improvement, optimization of airport facility, and flight paths.

The most representative way to reduce carbon emissions is to develop the biomass-based fuels such as bio-aviation oil with low carbon emission and their production technologies. Also, many international airlines have launched pilot projects for their application feasibility. However, it is difficult to secure economic feasibility in various cost aspects. In order to overcome these problems such as securing economic feasibility, developing bio-air fuels as well as setting international standards and providing incentives for the use of bio-fuels, which can be the basis for establishing carbon emission goals and policies of international airlines. In order to overcome such problems as securing economic feasibility, the international standards that can be the basis for establishing carbon emissions goals and

**Figure 3.**

*Future prospect for carbon emission from aviation industries (unit: million tons of CO2) [4].*

policies for international airlines should be established, and the bio-jet fuel market should be activated by securing technologies for developing bio-jet fuel fuels in addition to providing incentives for the use of bio-jet fuels. In order to achieve this goal, the ICAO established the Commission for Aviation Environment Protection (CAEP), and efforts to reduce aviation greenhouse gas emissions have been increasing, especially for ICAO. Developments are emerging, and countries and international organizations are stepping up their aviation bio-fuel development policies. The 38th ICAO General Assembly resolution approved the importance of aviation biofuels as a medium-to-long term GHG reduction measure, established a global framework, the possibility of sustainable drop-in aviation biofuel technology, and emphasis is placed on the need to introduce policies and incentives from a perspective of accelerating wide utilization. The IATA announces continued use of renewable energy as the most reliable way to meet its greenhouse gas reduction targets and requires by 2020 to replace 6% of aviation fuel demand with renewables. The various bio-fuel support policies are being promoted by spreading awareness that bio-fuels can contribute to greenhouse gas emission reduction, energy security enhancement, rural income, and new market development. These support policies include tax exemptions for bio-fuels in most countries, including budgetary support (tax exemption or direct subsidies to bio-fuel producers, sellers, and users), minimum mix ratios, and import tariffs on imported bio-fuels. In addition, subsidies are being used to support bio-fuel dissemination, resulting in \$ 20 billion in grants from governments around the world in 2009, mostly in the US and EU countries. The Korean government subsidies are expected to increase to US\$ 37.5 million annually from 2010 to 2020 and to US\$ 70.8 million annually from 2021 to 2035.
