Discussion on Quantitative calculation of greenhouse gas emissions in solid waste industry -- taking incineration plant as an example

Up to now, there are 876 urban solid waste incinerators in China, with a daily processing capacity of about 1 million tons. Incineration has become the main way of disposing of urban solid waste, accounting for 73% of the total. Therefore, scientific quantification of greenhouse gas emissions from incinerators is of great significance for the study of greenhouse gas emissions from solid waste treatment.

In the calculation of greenhouse gas emissions from incinerators, it is necessary to define the object and purpose of accounting. If regional accounting is carried out, under the premise of specifying the accounting scope of various sectors, in order to avoid repeated accounting, it is only necessary to calculate the direct greenhouse gas emissions caused by waste incineration, which generally only includes the emission from incineration and conversion of combustible components of waste. If the accounting is carried out for incineration plants or incineration enterprises, it needs to be considered more comprehensively and in detail in combination with the accounting objectives. The GHG Protocol Greenhouse Gas Accounting System and ISO 14064-1 Greenhouse Gases - Part 1: Guidelines for Quantification and Reporting of greenhouse gas Emissions and Removal at the Organization Level are commonly used methods for accounting for greenhouse gases at the organization level. The document divides greenhouse gases into three main categories: direct emissions, indirect energy emissions and other indirect emissions.

In general, when we do greenhouse gas accounting, direct emissions need to be taken into account. Indirect emissions, especially other indirect emissions other than energy emissions, are sometimes difficult to obtain data due to their various types and complex links, and have little impact on greenhouse gas emissions. Therefore, we need to give consideration to the operability and accuracy of accounting while fully reflecting greenhouse gas emissions, and make a choice about indirect greenhouse gas emissions.

ISO 14064-1:118 states that when determining indirect greenhouse gas emission sources, criteria for significance of indirect emissions should be established based on the intended use of the accounting. Using these guidelines, the organization should identify and evaluate its indirect greenhouse gas emissions to select significant indirect emissions. Criteria for assessing significance may include the order of magnitude of emissions, the level of influence of emission sources, access to information and the level of accuracy of relevant data.

Combined with the operation characteristics of incinerators, we preliminarily put forward two criteria for determining major emission sources of incinerators:

(1) Significant indirect greenhouse gas emissions should reflect the operation effect of the incinerator.

(2) Significant indirect greenhouse gas emissions shall not be less than 1% of the overall greenhouse gas emissions of the incineration plant (regardless of emission reduction benefits).

According to Criterion (1), when considering "other indirect emissions", factors such as upstream transport distance of household waste and raw materials and type of vehicle fuel used are not controlled by incineration enterprises, so emissions from other vehicle transport can not be included in the accounting scope. The use of raw materials, the scale of net purchased power and heat, and the downstream treatment and disposal of by-products can reflect the operational level of the incineration plant and should be included in the major indirect emission sources. Criterion (2), on the other hand, requires the identification of negligible emission sources based on a large amount of actual data accounting.

Source: https://mp.weixin.qq.com/s/BosMbR_WoK12mTJiEOw8Hg