A few alternatives to replace nuclear power would include:

-using geothermal heat, which is obtaining power using the Earth's interior heat, is a good alternative source of energy because it is environenmentally-friendly as it does not emit CO2 or other greenhouse gases in the process. And Indonesia is a good country to use geothermal heat because "Indonesia sits atop one of the best geothermal heat sources on this planet. The islands formed over a vast subduction plate boundary where the Eurasian and Australian plates are in collision. These processes are still very active. About 200 volcanoes are distributed across the Indonesian island arc and many of the areas which surround them could host viable geothermal power plants." [1]

-hydropower, which is obtaining energy using moving water, is environmentally-friendly because it does not emit CO2 or other greenhouse gases in the process. Although Indonesia has high hydropower potential, because of its hilly terriains and high precipitation all year round, this potential is highly untapped because "the greatest potential (over 35%) is in Irian Jaya, which has less than 1% of total electrical demand, while Java, with about 80% of the demand, has less than 10% of the total potential, most of which has already been developed" [2]

-natural gas, which is using liquified petroleum gas to generate elecity, is not a good source of energy because it is depleting the country's natural resources. Furthermore, Indonesia is already running out of natural gas, "Indonesia is in danger of losing its dominance of the world's market for liquefied natural gas as its fields are running out of gas faster than expected."


[1] Taken from: http://geology.com/news/2006/11/indonesias-geothermal-potential.html
[2] Taken from: http://books.google.com.sg/books?id=fnNYtXaZpr0C&pg=PT49&lpg=PT49&dq=indonesia+hydropower&source=web&ots=
dHJveo74fM&sig=3LkRKGI_bGPQ-LQOoPHF4jLuges&hl=en
[3] Taken from: http://www.iht.com/articles/2006/08/09/bloomberg/bxgas.php