Dissertation: Methodology (6 of 8) - Parameters

C.    Parameters

It was outside of the purview of this study to perform a full LCA of all of the types of generation technology. However, Weisser (2007) reviews numerous LCA studies that analyze the GHG emissions associated with the various types of electricity generation simulated in this study. The review offers a range of GHG emissions for each type of generation based on different LCA techniques applied to different generation sites throughout the developed world, and all of the values included in the review are directly attributable to a particular, recent study with original data (Weisser 2007). As a spot check on the Weisser (2007) article, the results of the Jaramillo et al (2007) article, which performed a comprehensive analysis of the LCA GHG emissions associated energy generated from combusting coal and natural gas (including synthetic and liquid natural gas) in North America, were also taken into consideration. Upon translating the results of both articles into similar units, it was found that the results were relatively similar. Please see Appendix D for a list of the original LCA results in both articles.

Table 3: This table displays the greenhouse gas emissions input parameters for all generation fuel types used in the model in all scenarios. Note that all values are from Weisser (2007).

Generation Fuel Type	Lower Bound Emissions	Upper Bound Emissions
Nuclear (LWR)	2.8 kgCO2e/MWh	24 kgCO2e/MWh
Coal	950 kgCO2e/MWh	1250 kgCO2e/MWh
Natural Gas	440 kgCO2e/MWh	780 kgCO2e/MWh
Oil	500 kgCO2e/MWh	1200 kgCO2e/MWh
Hydro (without ES)	1 kgCO2e/MWh	34 kgCO2e/MWh
Wind (On-Shore)	8 kgCO2e/MWh	30 kgCO2e/MWh
Solar (All PV types)	43 kgCO2e/MWh	73 kgCO2e/MWh

Thus, this study uses the values suggested by Weisser (2007) as the guiding parameters for GHG emissions rates (see Table 3). As such, all scenarios were run using the upper- and lower- bound of the ranges suggested for each generation fuel type. This safely allows an assumption to be made that the ‘true’ GHG emissions for each scenario would likely lie in between the values generated in the upper- and lower-bound trial runs. Unfortunately, due to the discrepancies inherent in LCA analysis, it is not possible to be any more certain about the results produced by the model.

It should be noted that the values for nuclear generation displayed in table three are only derived from studies about so-called ‘light water reactors’ (or LWR), which are currently a common type of nuclear reactor in use (Weisser 2007); however, as the grid is modernized newer types of reactors may be brought into service, so these values can only serve as a guideline. It should also be noted that the range of GHG emissions for solar generation include both types of photovoltaic panels (e.g. mono- and poly-crystalline) and that monocrystalline panels have a range of 43-62 kgCO₂e/MWh whereas polycrystalline panels have a range of 50-73 kgCO₂e/MWh (Weisser 2007).

Weisser (2007) also offers some LCA GHG emission values associated with some types of ES technologies; however, since this study is based on determining the direct GHG emissions (i.e. a portion of the full LCA value) associated with ES technologies, it did not seem prudent to attempt to integrate these values into the model. These omitted values can be found in Appendix D.

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