Discussion and conclusion
This paper reviewed the related literature on RE studies to identify ten criteria and used four MCDM (WSM, TOPSIS, VIKOR and ELECTRE) methods to rank the priority of five RES in Taiwan. The data were collected from various official institutions or related studies. The results of analysis show that technology is the most important factor for the evaluation of RES, followed by financial, environmental, and social factors. In addition, efficiency, job creation, and O&M cost are identified as the first, second, and third priorities within all criteria. These results imply that the development of Taiwan's RE should consider whether the technology is mature and stable, and power generation is efficient enough. It is necessary to evaluate the capability of electricity generation to decrease the reliance on fossil fuel. Additionally, cost is another critical factor for decision makers in the evaluation of a RE program. However, by improving the RE technology, the cost will be decreased. The environmental factor is becoming increasingly important due to the rise of environmental protection awareness in recent years. The social factor is usually the last consideration. The calculated weight of each criterion obtained in this paper is partially consistent with the results of past studies using AHP subjective weights. Ahmad and Tahar [22] found efficiency is considered to be an important criterion, while social acceptance and land use criteria are less important. Except for land use, their weight rankings are consistent with ours. Theodorou et al. [81] indicated that investment cost is the most important criterion, followed by efficiency, technological implementation potential, maturity and people's acceptance. Their results also indicate that efficiency is important and residents’ acceptance is the least important.
