Plans for hydro-electric projects on Otago's Clutha River are being dusted off more than a decade after they were dropped.
Contact Energy is taking another look at the schemes, which were proposed at Luggate, Queensbury and Tuapeka.
The plans were investigated in the late 1980s and early 1990s before Contact's predecessor, ECNZ, abandoned the ideas in 1996.
Contact chief executive David Baldwin says his company is thinking beyond geothermal and wind generation to the future sources of electricity.
"If we were to think about hydro, as we think about geothermal today, as an alternative to say natural gas - particularly when you have to import that natural gas - then hydro may be an option that's more palatable than it has been over the last five to 10 or 20 years or so."
Mr Baldwin hopes the projects will be under way by 2015.