The EU Acidification Strategy: Sensitivity of calculated emission ceilings for nitrogen and sulphur for Denmark

The sensitivity of the calculated emission ceilings to changes and uncertainties in preconditions used in the cost-effective optimisations for the EU Acidification Strategy is evaluated and the uncertainties on the optimisations are discussed. The total uncertainties on the deposition targets are estimated to be in the range of 20-30% and depend on uncertainties in the deposition calculations, in the critical loads calculations, and the shape and number of receptor points in the cumulated frequency distribution curve used for the optimisation. Using this uncertainty range it is found that the deposition target in a limited number of grids has a significant influence on the cost of the optimal solution for Denmark. The emission ceilings for Denmark are sensitive to changes in the input energy scenario, but the sensitivity to changes and uncertainty in marginal costs is limited. The use of new emission factors for ammonia in Denmark has the potential to change the emission ceilings for SO2 and NOx allowing higher emissions for the energy sector.