Where are greenhouse gases emitted?

Greenhouse gas emissions are dominated by CO2 emissions. These are the highest in industrial areas (such as Rijnmond and Velsen) and in municipalities where power stations are located (such as Geertruidenberg and Diemen). Two thirds of methane emissions come from animal farming and these are focused in areas like eastern Noord-Brabant with its intensive pig farms. Nitrous oxide escapes mainly from industry located in Sittard-Geleen and from intensive livestock farming such as in Friesland.

How are regional emissions determined?

The information on which the national totals are based comes from two different sources, known as point sources and diffuse sources. Point sources are derived from the legally required reporting of emissions by companies by means of an electronic Environmental Annual Report (known in Dutch as an e-MJV). The exact location of each e-MJV report is known, and so emissions from all point sources can be assigned to an exact location.

Diffuse sources include emissions from passenger cars, for example. In a sense, these are also point sources, but it is unknown where each car was driven and therefore where the emissions took place. Total emissions are therefore modelled, instead. For road traffic, the total number of kilometres driven is used to calculate emissions. For example, a road that accounts for 5 percent of total kilometres driven will be allocated 5 percent of the relevant emissions total. Diffuse sources are also spatially distributed in a similar manner. The model used for some emission sources is more complex than for others. The quality of the data behind the allocation models also varies.

The lowest spatial level at which emissions are determined is that of 1x1 km squares and 5x5 km squares. Municipal figures are compiled from these. These can then be aggregated by COROP region, province or district.

The spatially distributed figures represent a model of reality. This gives a good picture of the regional distribution of emissions, but will not match actual emissions exactly for every 1 x 1 km square. There are also margins of uncertainty regarding national emissions figures.

For all greenhouse gases combined, the margin of uncertainty with respect to the national total is 3 percent. For carbon dioxide (CO2), which represented an 84-percent share of emissions in 2021, the margin of uncertainty was also 3 percent. For methane (CH4), nitrous oxide (N2O) and the fluorinated gases, the emissions shares are 11, 4 and 1 percent, respectively, and the corresponding margins of uncertainty are 9, 34 and 24 percent. How these margins of uncertainty play out at the regional level depends on the exact location. For many locations, the margin of uncertainty will be higher. But for a location with a single major point source and where the emissions are known fairly precisely, the uncertainty margin will be lower.

The shares of CO2, CH4, N2O and fluorinated gases in total greenhouse gas emissions were determined by converting the volumes emitted into kilograms of CO2 equivalent. The emission of 1 kg of CO2 equivalent has the same effect as emitting 1 kg of carbon dioxide. The emission of 1 kg of nitrous oxide is equivalent to the emission of 265 kg of CO2, while the emission of 1 kg of methane is the equivalent to 28 kg of CO2. Fluorinated gases are significantly more potent greenhouse gases: for example, 1 kg of sulphur hexafluoride (SF6) is equivalent to 23.5 thousand kg of CO2.

These conversion factors have been applied since mid-September 2022 due to new IPCC regulations. Before that, the conversion factors for nitrous oxide, methane and sulphur hexafluoride were 298, 25 and 22.8 thousand, respectively.