The Emissions Trading Centre at the Federal Environment Agency collects the latest data on greenhouse gas emissions. All plant operators subject to emissions trading (power plants, large industrial companies) are obliged to report their actual emissions to the centre every year.

However, these emissions reports have not yet been systematically compared with the data from national climate protection reporting. Climate reporting calculated all German emissions, including those from sectors not subject to emissions trading (e.g. small industrial companies, households, transport, agriculture). The IZT study prepared an anonymised comparison between the two strictly separate databases. As a result, national climate reporting should fulfil stricter international requirements. This was the prerequisite for participation in international emissions trading and other flexible mechanisms in accordance with the UN Framework Convention on Climate Change (UNFCCC).

In Germany, greenhouse gas (GHG) emissions were recorded in the two separate systems of emissions trading (ETS) and emissions reporting (National Inventory Report - NIR): Under the ETS, data from the German Emissions Trading Authority at the Federal Environment Agency (DEHSt) was recorded in accordance with monitoring reports from the plant operators subject to emissions trading. This corresponds to a bottom-up approach and reflects the actual emissions of the installations. The focus was more on the output of the processes causing the emissions. In contrast, the GHG emissions for the NIR were recorded in the Federal Environment Agency's emissions database (ZSE) using a top-down approach. The emitters were structured in accordance with the IPCC and also according to energy statistics criteria, plant/combustion technology and immission control categorisation. The focus of the analysis was more on the input of the processes causing the emissions.

Overall, the data from emissions trading could be regarded as the most up-to-date empirical data at the time, as the activity rates on which the NIR was based, in particular, as they came from the Energy Balance Working Group, were not available in a timely manner, but were often only of a provisional nature as an evaluation table. For this reason, the use of ETS data for emissions reporting was in the decisive interest of quality assurance and improvement in the sense of utilising the best available data. However, the strict data protection regulations for the plant-related data of the ETS had to be observed.

The project involved the comprehensive processing of anonymised emissions trading data for comparison with the data from national climate reporting. On the one hand, this required a syntactic interpretation and aggregation of material and batch information. On the other hand, quantitative analyses were used to determine and validate the degree of coverage of the emissions reported for the whole of Germany by the emissions of the ETS. The focus was on emissions from refineries, coking plants and the iron and steel industry. In addition, the data available at DEHSt at the time on the additional types of installations subject to emissions trading from 2013 were analysed and interpreted.

As a result, national climate reporting was validated in order to fulfil the increasingly stringent international requirements, which were also a prerequisite for participation in the flexible mechanisms (emissions trading, Joint Implementation, Green Development Mechanism) under the UN Framework Convention on Climate Change (UNFCCC).