**2.2 GREET**

The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model (GREET) was developed by Argonne under the auspices of the US Department of Energy (Energy Efficiency and Renewable Energy) [6]. It is a program that enables LCA of energy usage and emissions that occur during production and transportation of fuel as well as the driving of the vehicle. Also, it can accumulate data on a wide range of data, including moving parts in the picking and transportation production of raw materials. It is calculated based on actual measurement results rather than simulation results. In addition to gasoline and diesel, there are data on full-range fuels used in transportation such as natural gas, electricity, and bio-oil. Not only energy consumption but also exhaust gas and greenhouse gas emissions are investigated, and it is very useful for comparative analysis under the purpose of life cycle assessment. GREET includes more than 100 fuel routes, including petroleum and natural gas fuels, as well as biofuels, hydrogen, and electricity from a variety of energy sources. It is easy to compare and analyze the effects of each stage in the calculation by dividing the process from fuel production to supply. It provides the sources, usage from, contents of the data used in the GREET development process in the public domain.

## **2.3 LCA method**

Well-to-hull processes of marine fuel and LNG are described in **Figures 3** and **4**. To evaluate the environmental impact of diesel compared to natural gas, we use GREET to compare the following WTP processes. In the case of natural gas, it is expected that more greenhouse gases will be generated than diesel due to the amounts of leaks generated during production and processing. However, compared to diesel, the amount of traffic generated during transport is expected to be good enough to reduce the above disadvantages. To compare and analyze this, we want to compare and analyze the operation part using GREET and WTP analysis, PTH data [7].

In the case of the WTP process, it is difficult to obtain reliable data, and there are a lack of extensive data on each process. To solve this problem, we would like to compare and analyze the results using the following GREET results.

**Figure 4.** *Well-to-hull process of LNG [1].*
