7.0 yr

Table 26-22 Economic Performance Summary Under Sensitivity Analysis 1.

Table 26-22 Economic Performance Summary Under Sensitivity Analysis 1.

payback than the gas turbine-based system.

Sensitivity Analysis 2

To the extent that other load and cost reduction opportunities show superior economic performance to that of the electric cogeneration project options, they should generally be considered first. This concept is commonly referred to as an integrated approach to energy use optimization. As such, the cogeneration system options would then be considered based on the new operating load and cost profiles that would result from implementation of the other measures.

This sensitivity analysis considers the interactive impact of one such measure. At the facility, there is a highly cost-effective option that would improve the energy and water use efficiency of a dying process through application of thermal and water recovery technology. The simple payback for this technology application is 2.0 years, making it extremely attractive to the facility. Assuming that this measure would be installed, the potential to use the recovered low-temperature heat from the reciprocating engine in the form of hot water would be greatly reduced, thereby reducing the economic performance of that system option. The gas turbine system would be affected, but to a much smaller degree, since during most operating hours the total steam load remains in excess of the gas turbine plant production.

Starting with the first sensitivity analysis that shows superior economic performance for the reciprocating engine system option, the simulation was run again, this time based on the new load profile that would result from the implementation of the thermal and water recovery measure. Changes modeled by the simulation include a reduction of 15,000 lbm/h of hot water heating steam load during most hours and the elimination of the heat recovery hot water distribution system from Case RE-1. The resultant cogeneration system economic performance analysis is summarized in Table 26-23.

These results show that, as expected, the reduction in process hot water load will have a greater impact on the reciprocating engine configuration than on the gas turbine configuration. As such, under these site-specific conditions, the gas turbine system now shows superior economic performance.


The key conclusions to be drawn from the previous analytical examples are that:

1. A pre-screening process should be used to limit the number of options to be studied in detail.

2. A rigorous technical and economic performance analysis will be required to make a reliable financial investment decision.

3. Rules of thumb should not bias the selection process.

4. Site-specific conditions must be carefully identified and applied to system performance evaluation.

5. Technology applications should be viewed within an integrated approach that considers the interactive effects of other viable facility improvement options.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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