Emission forecasting example

Another aspect of matching output to user needs involves presentation of results in a statistical framework—namely, as frequency distributions of concentrations. The output of deterministic models is not directly suited to this task, because it provides a single sample point for each run. Analytic linkages can be made between observed frequency distributions and computed model results. The model output for a particular set of meteorologic conditions can be on the frequency distribution of each station for which observations are available in sufficient sample size. If the model is validated for several different points on the frequency distribution based on today s estimated emission, it can be used to fit a distribution for cases of forecast emission. The fit can be made by relating characteristics of the distribution with a specific set of model predictions. For example, the distribution could be assumed to be log-normal, with a mean and standard deviation each determined by its own function of output concentrations computed for a standardized set of meteorologic conditions. This, in turn, can be linked to some effect on people or property that is defined in terms of the predicted concentration statistics. The diagram below illustrates this process ... 

Most phase I NAPs provide for NE allocations based on a general emission rate and predicted activity level. For example in The Netherlands (NL), new entrants are allocated allowances based on projected output or fixed cap factor multiplied by uniform emission rate in line with that of a combined-cycle gas turbine (CCGT). In France, Germany and Poland, C02-intensive power generators, such as coal-fired installations, receive the highest number of allowances per kW installed. The literature highlights the risk that NE provisions can create distortions (Harrison and Radov, 2002). In order to illustrate how these rules can impact electricity prices and C02 emissions in our GB simulations, we focus on two approaches one based on a uniform benchmark and one based on a fuel-specific benchmark. In both cases the forecast capacity factor of new entrants is fixed at 60%. 

In determining which model to use, the analyst needs to determine what outputs or results are needed to successfully accomplish the desired objectives of the study. Factors that should be considered include the level of regional detail, the forecast period, the pollutants to be considered, and the sectoral detail desired. Available funds and resources for running a model also need to be taken into account. For example, if a control strategy affecting all emission sectors is proposed, then a model examining only, say industrial emissions may not be sufficient. Interaction between emission source sectors and the capability of the models needs to be considered. 

This has led to a strong decrease in sulfur emissions caused by transportation fuels for road traffic. For example, in 1975 and 1990, respectively, 100000 and 86000 tonnes of SO2 were emitted in Germany (only road traffic), whereas in 1999 the amount had fallen to 26 0001 SO2. [For comparison overall SO2 emissions (Germany) 7.5 mio. t in 1975, 5.3 mio. t in 1990, and 0.8 mio. t in 1999]. Thus the share of road traffic on the overall SO2 emissions is in many industrialized countries today much less than 10%. Today, less than 50ppmw (mostly even < 10 ppmw) sulfur in gasoline and diesel oil is mandatory in industrialized countries, and fuels with even less sulfur are or will be on the market due to tax benefits. A similar trend can be forecast for countries in Asia such as China and India (Table 6.8.2), where until recently the sulfur limit has been much higher. 

GHG emission reductions in the short-term will be limited as sustainable alternative fuels for aircraft are initiaUy introduced. For example, assuming the lifecycle CO2 footprint of sustainable alternative fuels for aircraft provides a 20% reduction compared with conventiraial jet fuel, and a 50% fuel blend makes up 10% of the total jet fuel market, the GHG emissions reduction would be 1% compared to forecast emissions without the new fuels. However, reductions in particulate matter and sulphur oxides will be more signihcant Achieving air quality benehts from the use of these fuels is independent of production life-cycle considerations. 

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