Methodological Study on Voluntary Greenhouse Gases Reduction for Shore Power System

Voluntary emission reduction of greenhouse gases is conducive to reducing carbon dioxide (CO2) emissions and fostering a carbon trading market. Voluntary greenhouse gas emission reduction methodologies can be used to determine project baselines, demonstrate additionality, calculate emission reductions, and develop monitoring plans. Marine fossil fuel combustion is an important source of greenhouse gas emissions in port. Through the implementation of marine shore power system, it is possible to replace fuel consumption with electricity and significantly reduce greenhouse gas emissions during berthing. Through the analysis and study on shore power system, the methodology of voluntary greenhouse gas emission reduction for shore power system is formed, which is conducive to promoting the participation in carbon emissions trading and promoting the promotion and use of shore power system.

Greenhouse gas emissions in ports mainly come from the production of loading and unloading and the burning of fossil fuels during the berthing period of ships. The implementation of shore power system can effectively control greenhouse gas emissions in port areas. Such projects have the characteristics of large scale, significant energy saving and emission reduction benefits. It is suitable for carrying out voluntary emission reduction trading as a typical project of transportation industry. At present, China has basically built a voluntary greenhouse gas emission reduction trading and its supporting system. The National Development and Reform Commission promulgated the Interim Measures for the Management of Voluntary Greenhouse Gas Emission Reduction Transactions [1] and the Guidelines for the Verification and Certification of Voluntary Greenhouse Gas Emission Reduction Projects [2]. In the field of transportation, some methodologies have been published, such as "Reducing Emissions through Electric and Hybrid Electric Vehicles (Methodology No. CMS-048-V01)" [3]. However, there is a lack of emission reduction certification methods for shore power system at present. In this paper, according to the requirements of voluntary greenhouse gas emission reduction trading, the methodology of voluntary greenhouse gas emission reduction is proposed for shore power system. 1 Methodological study

Definition and scope of application
(1)Relevant definition Shore power system: it means that during the period of berthing, the generator on the ship will be stopped and the power supply on land will be used instead.
Unit time fuel consumption: Fuel consumption per unit time of power generation by ship auxiliaries during berthing.
Unit time power consumption: Electricity consumed per unit time by shore power system during berthing.
(2) Explanation of scope of application This methodology is applicable to the calculation of emission reduction caused by the use of shore power instead of fuel during berthing of ships.
This methodology is limited to projects with annual emission reductions of less than 60,000 tons of carbon dioxide.
The principle of selecting all kinds of parameters is to select the measured data first.

Base line
In determining the baseline scenario, the baseline ship and the project ship (ships using shore power system during berthing) should provide comparable services. It is required that the power difference of fuel engine (including main engine and auxiliary engine) should be within ±20% respectively.

Project boundary
Project boundaries include: (a) Ships using shore power system during berthing. (b) Geographical boundaries of ports where ships berthing.
(c) Ancillary facilities such as shore power supply equipment and power sources (e.g. power grids).

Additional Demonstration
Mode 1: Demonstrate that project activities can't be implemented because of one or more obstacles, such as the obstacles faced by the construction of shore power system, the policy and regulation obstacles faced by power supply services (e.g. unclear price of power supply, policy-based market barriers), and mandatory laws and regulations.
Mode 2: Prove that the proportion of shore power in the project area is less than 20% before the implementation of the project.

Baseline calculation
The determination of the baseline is based on the unit time fuel consumption of engine power generation. It is obtained by multiplying the berthing time and the number of ships, the emission coefficient of the fuel used.
The calculation formula is as follows.
Among them: y BE :Baseline emission in Y year(t CO 2 ).

Project Emissions
Project emissions refer to the carbon dioxide emissions indirectly generated by ship power consumption.
The calculation formula is as follows.

Leakage
This methodology does not require calculation of leakage.

Emission reduction
Emission reductions are calculated as follows.
ER y =BE y -PE y -LE y (4) Among them: ER y ：Emission reduction in year Y(tCO 2 ). BE y： Baseline emission in year Y(tCO 2 ). PE y ：Project emission in year Y(tCO 2 ). LE y ：Leakage in year Y(tCO 2 ).

Monitoring indicators and methods
The monitoring indicators and methods for the project are shown in Table 1.     The measurement is carried out through the power supply monitoring system of the shore power system.

Example analysis
A shore power project in East China is taken as an example in this paper. According to the data provided by port company, all ships use fuel as power during berthing before the project, which meets the requirement that " It is required that the power difference of fuel engine (including main engine and auxiliary engine) should be within ±20% respectively". This project has additionality.

Project Activity Descriptions
The project achieves emission reduction by building shore power system and replacing fuel with electricity. Project emissions refer to the carbon dioxide emissions indirectly generated by ship power consumption. The annual electricity consumption of shore power is 13964 MWh. The monitored indicators are shown in Table 2.

Pre-calculation of emission reduction
(1)Baseline calculation The fuel consumption of marine auxiliary power generation is 245g/kWh, and the energy consumption ratio per unit berth time is: When diesel oil is used as fuel, the net calorific value of fuel oil is:42652J/g=42.652GJ/t.
The emission factor of fossil fuels is: 20.2t-C/TJ*44/12=74.067t-CO 2 /TJ=74.067*10 -3 t-CO 2 /GJ. Baseline emissions are calculated as follows. According to the above calculation, the first year emission reduction of this project is 2674.23 tons of equivalent carbon dioxide.

Conclusions
The burning of fossil fuels is an important source of greenhouse gas emissions from port ships. Through the implementation of shore power system, it is possible to replace fuel consumption with electricity and significantly reduce greenhouse gas emissions during berthing. This paper studied and analyzed the existing greenhouse gas emission reduction methodologies, and defined the requirements of baseline determination, additionality demonstration, emission reduction calculation and monitoring plan formulation for portbased power supply projects. It provided a basis for quantitative calculation for shore power system to participate in carbon emissions trading. The research results are helpful to promote the application of shore power.