In line with the policy of nuclear phase-out and achieving net-zero emissions by 2050 in Taiwan, offshore wind power has been recognized as a significant energy alternative. Developing a local supply chain not only facilitates the construction of renewable energy infrastructure but also benefits the macroeconomy. This study aims to elucidate the extent of economic benefits associated with offshore wind power development and to quantitatively assess the economic impacts during the construction and operation phases. Our numerical results support the economic significance of developing offshore wind power during both phases, as it promotes economic growth and employment. Furthermore, a comparison of the economic gains between the two phases reveals that the gain during the construction phase, primarily driven by local content supplied by domestic manufacturing, is much higher.