A businessman in the Cook Islands is planning a small hydro electricity operation to satisfy some of Rarotonga's night time power needs.
The pilot scheme will involve pumping water to a vast holding tank and then letting it run through turbines at night.
Lawyer Tim Arnold, who has been working with businessman Chris Vaile on the scheme, said it is a product of the Cook Islands' drive for renewable energy and with the focus on solar power, there will be power shortages at night unless the excess can be stored in expensive batteries.
Mr Arnold says their alternative is to use this excess energy during the day so it can generate power at night.
"We are looking at 7,000 cubic metres, which is 7,000 tonnes, being pumped up, flowing down a 150 metres and that will serve about 10 percent of the night-time capacity, and it will avoid the need, if the efficiencies are what we are hoping for, purchasing batteries equivalent to around $US8 million, we are told."
Mr Arnold said other sites for additional mini hydro schemes are also being looked at.