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Carbon Accounting

Carbon accounting is the evaluation of business activity by calculating and tallying how much carbon dioxide (CO2) they produce, as well as the degree to which business activities contribute to reducing CO2 emissions. As an initiative to address climate change, Mizuho Bank developed its own carbon accounting methodology to measure CO2 emissions and CO2 emission reductions by power generation projects it has financed. We began disclosing the results of our evaluations in fiscal 2006 and we are utilizing these results as information for future management to support the movement toward a low–carbon society.

Carbon accounting overview

Applicable projects

Each fiscal year, we apply our carbon accounting to new large–scale power generation projects for which financial agreements were signed in that year. This is because power generation plants typically emit substantial amounts of CO2 and these emissions can be calculated relatively easily based on the types of fuels and the annual energy production volumes generated by such facilities.

CO2 emissions

We compile a set of data detailing the CO2 emissions of each power project. CO2 emissions from power generation projects utilizing renewable energy sources are estimated as zero, in principle. However, in the case of geothermal power projects, greenhouse gases that leak out when steam is produced are included in the emissions data on a CO2–equivalent basis.

CO2 emission reductions

CO2 emission reductions are calculated by using the "Average for All Power Sources" data for each country, as listed in the Appendix "Emission Factors for Electricity" of the J–MRV Guidelines published by the Japan Bank for International Cooperation (JBIC). Specifically, for each power project, the assumed CO2 emissions calculated using each country's average emission factor is used as a baseline, and when the project's CO2 emissions are less than the baseline, the difference is defined as a CO2 emissions reduction. At Mizuho Bank, we compile CO2 emission reductions for power generation projects with renewable energy sources.

Mizuho Bank's contribution to CO2 emissions and CO2 emission reductions

Our contribution ratio (c)% is the ratio of the financing amount we provide to a project's total cost.

"Contribution to CO2 Emissions" and "Contribution to CO2 Emission Reductions" are defined as the project's CO2 emissions and CO2 emission reductions as described above, multiplied by our contribution ratio for a project. For example, if a natural gas–fired power plant project generates CO2 emissions of [a] tons and Mizuho Bank's contribution ratio is (c)%, then our contribution to CO2 emissions in tons would be [a] multiplied by (c)%. If a wind power project contributes CO2 emission reductions of [b] tons, our contribution to CO2 emission reductions in tons would be [b] multiplied by (c)%.

Result of evaluations

Contributions to CO2 emissions and CO2 emission reductions for power generation projects subject to carbon accounting

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(Unit: kiloton of CO2)
FY 2013 2014 2015 2016 2017
Contribution to CO2 emissions 930 1,961 1,136 4,132 1,559
Contribution to CO2 emission reductions 583 1,213 465 687 743
  • Note: Prior to fiscal 2016, greenhouse gas emissions from geothermal power facilities were not included in CO2 emissions and CO2 emission reductions calculations, and Contribution to CO2 Emission Reductions was calculated using a baseline of assumed CO2 emissions by a coal–fired power generation plant.

Number of projects by types of fuel subject to carbon accounting

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(Unit: Number of projects)
FY 2013 2014 2015 2016 2017
Renewable energy power plant projects Wind 2 9 5 5 2
Solar 21 10 16 14 8
Hydro 1 2 0 0 0
Geothermal 1 1 0 1 1
Biomass 0 0 0 0 0
Fossil fuel–fired power plant projects Coal 0 1 1 6 2
Oil 0 0 0 0 0
Natural gas 6 18 7 4 1
Total 31 41 29 30 14