HELCO seeks long-term water lease for 2 hydro power plants

Hawaii Electric Light Co. is seeking a long-term water lease for its two small hydro power plants on the Wailuku River.

HELCO uses a revocable permit to divert water through the stations but is seeking a 65-year lease from the state Department of Land and Natural Resources to comply with new recommendations from an agency task force. The water, which runs a turbine, is returned to the river.

The Waiau and Pu‘u‘eo power stations have a current combined capacity of 4.55 megawatts, but that would increase to 5.7 megawatts under proposed improvements.

According to a draft environmental assessment for the lease request, the Waiau station, built in 1920, would see one unit repowered with a new turbine with another rehabilitated. Automatic water level controls also would be installed.

The improvements are estimated to cost $6.2 million. Construction would begin in early 2019 and take nine months to complete, HELCO estimates. The Public Utilities Commission approved the plan in October.

That station is located mauka of Pe‘epe‘e Falls, while the Pu‘u‘eo station is located next to the Wainaku Street bridge.

HELCO spokeswoman Rhea Lee-Moku said hydro power stations, when running at full capacity, make up about 9 percent of Hawaii Island’s power generation. The improvements would notch that capacity up to about 10 percent.

Another 12.5-megawatt hydro station on the river is operated by an independent power producer.

A draft EA was recently published.

Email Tom Callis at tcallis@hawaiitribune-herald.com.