portuguese national inventory report on greenhouse gases, 1990

Base Year = 1001990199119921993199419951996199719981999200020012002200320042005200620072008200920102011Industrial ProcessesFigure 4.13 - Trend in Ammonia production140120100806040200The following sources of information where used to construct the above full time series.- total production of ammonia in Portugal is available from the only existingfacility for the period 1990-2008. In 2011 there is no ammonia production sincethe facility was stopped and the production relocated to India;- consumption of VRF feedstock could not however be determined from INEstatistical database, because differentiation of residual fuel oil for feedstock andenergy source was not clarified for this economic activity. Therefore, asexplained before, consumption of feedstock VRF was estimated from limitedinformation and relying on linear correlations: the quantity of VRF that was usedwas set from data collected at the only industrial plant in Portugal for a limitednumber of years – 1990 till 1994 – and a strong linear relation betweenfeedstock consumption and ammonia production could be established fromavailable data;- use of methanol was also estimated for the full time period from a linearregression which was determined from available information for a limitednumber of years.4.3.2.1.5 Uncertainty AssessmentNo specific guidelines exist in GPG (IPPC,2000) to estimate the uncertainty of this sourcesector. The greatest uncertainty of emission estimates for this source sector results from theuncertainty in knowledge of activity data (Feedstock consumption). Because the ratio offeedstock consumption over ammonia production was used to estimate feedstock consumption,the standard deviation of these ratios was used to estimate the error and then doubled toinclude an additional factor of conservativeness 63 . The final uncertainty value for activity datawas set as 31 percent.63 A further doubling was used to convert from standard deviation to 95% confidence interval.Portuguese National Inventory Report 2013MAMAOT4-22