Additional information on calculating conservative grid emission factor for
National Grid in Cambodia
It is concluded that applying different emission factors for displacement of grid or captive electricity
by a solar PV system in Cambodia, to achieve net emission reductions:An emission factor of 0.353 tCO2/MWh is applied for displacement of electricity from
Cambodian national grid.

An emission factor of 0.533 tCO2/MWh, which is the emission factor of the most efficientdiesel-fired power plant in the world, is applied for displacement of captive electricity.

1. Identifying grid emission factor for national grid in Cambodia
According to Electric Authority of Cambodia, all power units excluding captive power plants areconnected to National Grid that covers Phonm Phen and the provinces of Kandal, Kampong Speu,Takeo, Kampot, Sihanoukville, Kampong Cham, Kampong Thom, Prey Veng, Banteay Meanchey,
Battambang, Siem Reap, Pursat and Kampong Chhanang. National Grid imports electricity from
Viet Nam, Thailand and Lao PDR.

To ThailandBanteay Mean Chey
Siem ReapBattambang

Kampong ChhnagPursat

Kampong ChamKoh Kong

Kampong Speu

Phnom Penh
KandalPrey Veng

National Grid
Under construction

Takeo
KampotSihanoukville

To Viet Nam

Figure1: Map of Cambodian electricity grid system (existing and planning)(Source: Electric du Cambodge (2014) Annual Report 2014)1

Since the electricity from fossil-fuel power plants in Cambodia has the shares of 19% in 2013, 27%
in 2014 and 42 % in 2015, the electricity from a proposed PV project would displace not only
electricity from the fossil-fuel power plants, but also electricity from hydropower plant, othercountries, and biomass power plant. Thus, it is difficult to identify actual grid emission factors due tothe absence of sufficient dataset for electricity supply. In order to simply identify the conservativeemission factor for Cambodian national electricity system and to secure net emission reduction, thegrid emission factor in this methodology is established by a conservative operating margin that iscalculated with higher emission factors of power plants based on international standard than thedomestic one.

6,000
5,000

979
141

GWh

4,000

1,250

3,000

1,770

2,000
1,000
0
Hydro

2,128265863
1127474
169
1,003

1,839

2,1532013

2014

2015

Biomass

Coal (Lignite)

Oil

ImportSource: Author based on EDC internal data
Figure2 Electricity generation in Cambodia National Grid

2. Calculating operating margin in a conservative manner
For calculating the CO2 emission factor, heat efficiency of coal and oil-fired power plants needs tobe identified in a conservative manner. Considering, the lack of data, the world’s best heat efficiency
is applied due to the lack of power plant data. For the coal-fired power plants, 0.75 tCO2/MWh isapplied based on the lowest value of the maximum repayment term under the OECD’s arrangement
on officially supported export credits.

For the oil-fired power plant, 0.533 tCO2/MWh is applied in accordance with the approved JCM
methodology (PW_AM001)1, which is calculated by applying the default heat efficiency of 49%, anefficiency level which is above the value of the world’s leading diesel power generator. For thePW_AM001: Displacement of Grid and Captive Genset Electricity by a Small-scale Solar
PV System, https://www.jcm.go.jp/pw-jp/methodologies/18
12

emission factor of import electricity, hydropower plant and biomass power plant, 0 tCO2/MWh isapplied.

Table 1. Conservative emission factors of fossil-fueled power plants in Cambodia
Manufacturer
Plant efficiency
Reference(LHV)
Coal-fired power plant
0.750 tCO2/MWh
OECD (2016)Agreement on officially
supported export credit
Oil-fired power plant
0.533 tCO2/MWh
PW_AM001 “Displacement of Grid andCaptive Genset Electricity by a
Small-scale Solar PV System.”
Import electricity, hydro0 tCO2/MWh
power plant and biomass
power plant
Using the data of electricity generation and conservative emission factor for each power sources,
conservative operating margin is obtained, as follows:

Where:EFRE = The reference CO2 emission factor of grid [tCO2/MWh]EFi =Conservative CO2 emission factor of power source i[tCO2/MWh]

EGi = Electricity generated and delivered to the grid for power source i during 2013-2015[MWh]
As a result, operating margins of National Grid during 2013-2015 is calculated to 0.353 tCO2/MWh.
3. Emission factor of captive power plants
The emission factor of the most efficient diesel power generation is identified as 0.533 t-CO2/MWhin the additional information for the approved JCM methodology PW_AM001 “Displacement ofGrid and Captive Genset Electricity by a Small-scale Solar PV System.”3