Appendix 1

Additional information to the Proposed Methodology“Installation of Solar PV System”
It is concluded to apply the emission factor of 0.319 tCO2/MWh, which is the emission factor of the mostefficient natural gas-fired power plant in Thailand, for grid electricity and captive electricity displaced by asolar PV system in Thailand to achieve net emission reductions.

1. Background
Emission reductions are calculated by multiplying the amount of electricity displaced by the emission
factor of the grid electricity and/or captive electricity displaced. In order to secure net emission reductions,the emission factors in Thailand were studied.

2. Findings and rationales
2.1. Current status of electricity mix in Thailand
Natural gas-fired power plants has the largest share of the power supply in Thailand. The share has beenaround 70% of the total. The absolute amount supplied has increased during 2005 to 20131. The share ofcoal is on the increase and constitute around 20% of the power supply. The share of petroleum is onlyaround 1%. The combined margin (CM) emission factor of the grid for 2012-2014 is calculated to be 0.566
tCO2/MWh.
2.2. Power generation efficiency and emission factor of natural gas-fired power plants
An attempt was made to obtain a comprehensive dataset on the efficiency of natural gas-fired power plantsin Thailand. An enquiry was made to the Energy Regulatory Commission (ERC) regarding the efficiency ofnatural gas-fired power plants owned by the Electricity Generating Authority of Thailand (EGAT),
Independent Power Producers (IPPs) and Small Power Producers (SPPs) which started operation in theperiod starting from 1 January 2012 to 31 December 2015. However, no data has so far been supplied.
Another enquiry was made to an academic with a comprehensive knowledge on energy and emission
factors, and found that a dataset on the efficiency of natural gas-fired power plants do not exist.

A web-search was conducted to identify the most efficient natural gas-fired power plants in Thailand. The
power plants identified in the web-search are listed in Table 1. The most efficient power plant identified
through this exercise is owned by the Khanom Electricity Generating Co., Ltd. (KEGCO). The plant is
manufactured by the Mitsubishi Heavy Industry and has an efficiency of 61.2% (Lower Heating Value:LHV).

1

Organisation for Economic Co-operation and Development (OECD), Energy Statistics of Non-OECDCountries 2015, August 2015.
1

Although it has not been possible to confirm that this KEGCO power plant is the most efficient naturalgas-fired power plant in Thailand, the figure 61.2% is close or relatively higher than the most efficientgroup of natural gas-fired power plants in commercial operation in Japan, which has a LHV efficiency of56-59%.2

As stated in section 1, Emission reductions are calculated by using the emission factor of the grid electricity
displaced. But it is difficult to identify which of the natural gas-fired power plants is displaced by solar PV
system(s) installed in this project, and even if it is identified, it is difficult to calculate grid emission factor
due to the absence of such dataset. Therefore, the grid emission factor for displaced electricity isestablished by assuming that the most efficient natural gas-fired power plant in Thailand is displaced inconservative manner, which will lead to ensuring net emission reductions. It is assumed that the mostefficient natural gas-fired power plant in Thailand has an efficiency of 61.2% (LHV).

Table 1 Efficiency of natural gas-fired power plants in Thailand
Manufacturer
ProductCapacity
Plant efficiency(LHV)
Mitsubishi Heavy Industry3
M701F5488.5MW
61.2%
Siemens4
SGT-800
53 MW
56.2%
Siemens5
SGT5-4000F 782 MW
58.7 %769MW
Alstom6
GT26850MW
41.0%
Table 2 Constants for calculation of CO2 emission factor
ItemValues
Net calorific value of natural gas
1.02 MJ/scf
CO2 emission factor of natural gas

55.39 tCO2/MMscf

SourceA study on Thailand grid emission
factor 2014
A study on Thailand grid emission
factor 2014
Table 1

Plant efficiency (LHV) of most
61.2%*
efficient natural gas-fired power plant* Since auxiliary power consumption is unknown, the plant efficiency of gross electricity generation is2

https://www.env.go.jp/press/files/jp/24454.pdf
https://www.mhi-global.com/news/story/1308201706.html
https://www.mhps.com/en/products/thermal_power_plant/gas_turbin/lineup/m701f.html
34

http://www.siemens.com/press/en/pressrelease/?press=/en/pressrelease/2015/power-gas/pr2015090320pgen.htm&content[]=PG
http://www.energy.siemens.com/co/en/fossil-power-generation/gas-turbines/sgt-800.htm#content=Technica
l%20data
5
https://www.marubeni.com/dbps_data/news/2011/110620.html
http://www.energy.siemens.com/hq/en/fossil-power-generation/gas-turbines/sgt5-4000f.htm#content=Techn
ical%20data
6

http://www.alstom.com/press-centre/2014/12/alstom-signs-12-year-long-term-service-agreement-for-northbangkok-combined-cycle-power-plant/
http://alstomenergy.gepower.com/Global/Power/Resources/Documents/Brochures/gas-turbines-technical-performance.pdf
2applied. This ensures the calculation of a conservative emission factor.
The CO2 emission factor of power generation by natural gas-fired power plants can be calculated from theplant efficiency using the following equation.
CO2 emission factor of power generation [t-CO2/MWh]= CO2 emission factor of natural gas [tCO2/MMscf] / (Plant efficiency (LHV) [%] / 100) * 1,000 * 3.6 /(Net calorific value of natural gas [MJ/scf]*10^6)

Applying the values indicated in Table 2, the emission factor of power generation by the most efficientnatural gas-fired power plant of 0.319 t-CO2/MWh is derived. This value (0.319 t-CO2/MWh) is lower thanthe combined margin (CM) emission factor of the grid shown in Section 2.1. From this result, it can beconcluded that by applying the emission factor of power generation by the most efficient natural gas-fired
power plant for grid electricity displaced by a solar PV system will ensure net emission reductions.

Table 3 Efficiency and CO2 emission factor of natural gas-fired power plant
Plant efficiency of natural gas-fired power plant
CO2 emission factor ton-CO2/MWh

61.2%
0.319

2.3. Emission factor of captive power plants
The emission factor of the most efficient diesel power generation is identified as 0.533 t-CO2/MWh in theadditional information for the approved JCM methodology PW_AM001 “Displacement of Grid andCaptive Genset Electricity by a Small-scale Solar PV System.” This value is greater than the emission
factor of power generation by the most efficient natural gas-fired power plant in Thailand 0.319
t-CO2/MWh, derived in Section 2.2. In addition, it can be taken for granted that heating values of existing
natural gas-fired power plants for captive power generation is lower than the value of the most efficient one.
Therefore, the emission factor of the most efficient natural gas-fired power plant will ensure net emission
reductions for a project activity that displaces captive electricity by a solar PV system.

From the conclusions in this section and Section 2.2, it can be concluded that by applying the emission
factor of 0.319 tCO2/MWh, which is the emission factor of the most efficient natural gas-fired power plantin Thailand, for grid electricity and captive electricity displaced by a solar PV system, net emission
reductions is achieved.

3