The topic of climate and energy policy has drawn new attention since the Kyoto Protocol has now come into force. It is hoped that strengthened use of renewable energy sources can meet new international environmental requirements and provide self-sufficient domestic energy supplies. The decision support system established in this study integrates potential evaluations, cost analyses, legal incentives, and analysis of returns on investments with the aid of a geographic information system (GIS). This system can provide insights for policymakers into where and the extent of the potentials, for lawmakers into whether the current legal incentives are sufficient to encourage private investment, and for investors into whether investments in exploiting local renewable energy sources are economically feasible. Under the current incentive framework in Taiwan, the amortization periods of investment on renewable energy are generally longer than the period over which the investment is to be recovered. This presents an unfavorable condition for attracting investments to and for developing renewable energy. An increase in remuneration through legal revisions is needed before domestic investment in renewable energy will actively expand. (c) 2005 Elsevier Ltd. All rights reserved.