Hawaii County intends to re-harness the wind to power water distribution in South Kohala under a plan projected to save water customers $1 million a year.

The county Department of Water Supply has retained Lala­milo Wind Co. LLC to design, build and operate a wind farm with five turbines on 126 acres owned by the state between Wai­ko­loa Village, Kawaihae and Wai­mea.

The 199-foot turbines would help power eight wells supplying potable water to customers from Puako to Kawaihae, according to a draft environmental assessment published Monday for the proj­ect.

Hawaii County said in the assessment that it costs $3 million to $4 million a year to power the wells with electricity from Hawaii Electric Light Co. at 40 cents a kilowatt-hour. Wind power would save about $1 million annually by providing 75 percent to 80 percent of the well system’s energy needs.

An old wind farm that was built in 1985 with 120 turbines helped power the wells until those turbines were removed in 2010. The new turbines would provide a little more power than the old ones, 3.3 megawatts compared with 2.7 megawatts.

The assessment said the new farm will cost $13 million and have a 40-year useful life span, though the county has agreed to a power purchase agreement with Lala­milo Wind for 20 years, after which the county would decide whether to extend operations or decommission the farm.