With all of the health and environmental impacts of NOx, it’s little wonder that it is being targeted by legislation.
In Europe, maximum allowable NOx emission limits have been set by the European Parliament. However, more stringent emission limits can be determined by each individual member state, as well as local authorities.
Thanks in large part to the EU’s legislative focus, the continent has already seen significant reductions in NOx emissions. According to the European Environment Agency (EEA), NOx emissions were reduced by 44% between 1990 and 2011. Although European nations have made great strides in emission reductions in recent decades, restrictions on emission limits have become increasingly stringent.
An EEA analysis carried out in 2018, concluded that setting strict and realistic emission limits for the energy sector could lead to a 50 to 91% reduction in key pollutant emissions, including NOx, by 2030. To get there, the EU has set NOx emission criteria for both Large Combustion Plants (LCPs) and Medium Combustion Plants (MCPs).
Since 2011, the Industrial Emissions Directive (IED) has set maximum emission limit values for LCPs (≥ 50 MWth), as well as waste incineration (WI) and co-incineration plants. The IED states that sites have to use Best Available Techniques (BAT) in order to be granted environmental permits. Local authorities have to set emission limit values in the environmental permits for specific sites so that the actual emissions do not exceed the BAT associated emission levels (BAT-AEL) as specified in the BAT conclusions (BATC) for LCP and WI (BATC LCP and BATC WI).
Medium combustion plants (MCP), which have a thermal input between 1 and 50 MWth, are regulated by separate legislation that sets EU-wide emission limit values for NOx, sulphur dioxide (SO2) and dust.