Yen-lien Kuo Department of Economics and Graduate Institute of Political Economy, National Cheng Kung University   Department of Economics, No.1, University Road Tainan City, Taiwan 701 Rep. of China (R.O.C.)   yenlien@mail.ncku.edu.tw   http://home.educities.edu.tw/ylkuo/           JEL Areas: Q5 : Environmental Economics: General Q4 : Energy: General