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Economical – environmental evaluation of natural gas and renewable energy systems


Correspondence: P. Akbar Akhgari, Department of Environmental Science, Science and Research Branch, Islamic Azad University, Tehran, Iran.



Although the energy crisis has been slightly abated in the recent times, the possibility of a crisis caused by extremely high oil prices is still imminent. Simultaneously, the environmental crisis represented by climate change is further the major concern which requires an immediate solution. Hence, in this research, economical and environmental assessment of utilizing renewable energies in comparison with natural gas have been investigated which resulted to choose the best economically–environmentally alternative for power generation.

Equivalent uniform annual value and scaling-weighting check list with experts' comments through analytical hierarchy process have been applied for economical and environmental assessment, respectively. Afterward, the results of normalized economical and environmental assessment have been coalesced to gain a combined economical–environmental perspective.

As economical surveys, four scenarios have been considered. The results reveal that the best choices are conventional steam cycle, combined cycle, and biogas if power is sold to consumer (other technologies have negative net present value in this scenario), respectively, without considering the social costs and the emission reduction. If power is sold to government, biogas, conventional steam cycle, combined cycle, and wind are technological priorities.

In case of considering social costs and emission reduction incomes, the best choices are biogas, combined cycle, and conventional steam cycle, respectively, if power is sold to consumers. If not, the priorities are biogas and wind.

Furthermore, environmental surveys have indicated that wind is the most applicable environmentally friendly energy to produce electricity with negative impact magnitude (NIM) of 1.3 (out of 10). In addition, photovoltaic, biogas, and hydropower remain at the next levels with NIM of 1.6, 1.7, and 3.2 (out of 10), respectively. While conventional steam cycle has 6.2 of NIM.

Eventually, the combination of economical and environmental evaluation reveals that wind farms and biogas plants with normalized weight of 3.10 (310%) and 2.34 (234%) are the best choices of electricity generation method, respectively. Moreover, the least applicable one is conventional steam cycle with normalized weight of 0.63 (63%).

To sum it up, wind farms and biogas plants are about five and four times more economical–environmental beneficial than conventional steam cycle power generation. Copyright © 2012 John Wiley & Sons, Ltd.