Appendix 1

Additional information to the Proposed Methodology“Introduction of High Efficiency Electrolyzer in Chlor-Alkali Procesing Plant”

1. Calculation of electricity consumption of the reference electrolyzer
The electricity consumption of the reference electrolyzer is calculated by the electricity consumption of theproject electrolyzer (which is monitored) and ratio of specific electricity consumption (SEC) between
reference and project electrolyzer, as follows:ECୖ୉,୮ = EC୔୎ ×
whereSECୖ୉,୮
SEC୔୎,୮

ECRE,p:

ECPJ,p:

SECRE,p :SECPJ,p:Electricity consumption of the reference electrolyzer
during the period p [MWh/p]
Electricity consumption of the project electrolyzer during
the period p [MWh/p]
Specific electricity consumption of the referenceelectrolyzer [ kWh/t-NaOH]
Specific electricity consumption of the project electrolyzer[ kWh/t-NaOH]

SEC of the project electrolyzer (SECPJ,p) is set to be the value of the initial performance test by
manufacturer of the project electolyzer. SEC of the reference electrolyzer (SECRE,p) is the default values
set in the next section.

2. Specific electricity consumption (SEC) values of the reference electrolyzer
2.1. SEC values of electrolyzers
Japan Soda Industry Association made SEC of electrolyzers in Japan available in their web site1. The
average SEC is 2379 kWh(DC)/t-NaOH in 2014, which is described with blue line in in Figure.1 bellow.
It is noted that there are 30 plants in Japan and all plants introduced the electrolyzer of Ion-exchange
membrane method (IEM), and the SEC value is calculated based on the provided result from each plant.

On the other hand, according to a document “Best Available Techniques (BAT) Reference Document forthe Production of Chlor-alkali” (European Commission, 2014), the average of bipolar ion-exchange
membrane electrolyzers is reported as 2574kWh(AC)/t-Cl2. which is almost equal to 2281
kWh(AC)/t-NaOH. Hence the value is calculated to be within the range of 2191kWh(DC)/t-NaOH to2236 kWh(DC)/t-NaOH assuming the general AC/DC efficiency of 96% to 98%, which is described with

1 “Trends in electricity consumption, purchased / private electrify, and the power consumption rate” Japan Soda Industry
Association, http://www.jsia.gr.jp/explanation_05.html

1yellow line in in Figure.1 bellow. .

In addition, the operating SECs of the existing bipolar ion-exchange membrane plant in Saudi Arabia werecollected within the range of current density from 2.9 kA/m2 to 5.4 kA/m2, taking the same current density
ranges as those documented in the above mentioned document by European Commission. The values areplotted with the black dot in Figure.1 bellow. The averaged SEC and current density is calculated as 2210
kWh(DC)/t-NaOH and 4.14kA/m2 respectively, which are plotted with the orange dot in the Figure.1
bellow.

As a result, it is considered that the electrolyzer at the exiting bipolar ion-exchange membrane plant in
Saudi Arabia has comparable efficiency advantage as it has the efficiency level of almost equivalent to theperformance of electrolyzers reported in the document published in EU.

Figure 1: SEC values of electrolyzers

2.3. Determination of SEC values of the reference electrolyzer in Saudi Arabia
In order to calculate reference emissions, SECs of an initial performance test for the electrolyzer at theexiting bipolar ion-exchange membrane plant in Saudi Arabia was collected in order to make it comparable
to the SECs of project electrolyzer which are also based on an initial performance test. An initialperformance test is conducted at the time of installation by manufactures to check that the installed
electrolyzer operates properly. Therefore, the designed SEC value for initial performance value of existing
electrolyzer is adopted as the SEC values of the reference electrolyzer.

Considering the fact that the initial performance test is conducted based on production plan of chlor-alkali
and it varies for each plant, as well as that SECs are positively correlated with CD, the reference SECs are2

set into five range of CDs. Accordingly, the default values of reference SECs are as shown in Table 1
below.

Table 1: The reference SECs values set as default values in this methodology
CD (Current density) [ kA/m2] of performance
Default value of specific electricity consumption
guarantee by manufacturer of the projectof the electrolyzer [ kWh/t-NaOH]
electrolyzer
4.0 ≦ CD ＜ 4.52045
4.5 ≦ CD ＜ 5.02088
5.0 ≦ CD ＜ 5.521315.5 ≦ CD ＜ 6.02174
6.0 ≦ CD ＜ 6.52217

3. Aged deterioration of SEC in electrolyzers
It is known that SEC worsens with operation time because of deterioration of ion-exchange membranes andelectrodes. It is considered that deterioration rate and its effect on SECs are same on both reference andproject electrolyzer from the result of interviews from the manufacturers. Accordingly, deterioration rate is
not taken into account in the methodology as the reference emissions are calculated based on the ratio ofSECs between reference and project electrolyzer.

3