The Natural Energy Laboratory of Hawaii Authority is seeking tenants to fill an alternative-energy and biotechnology demonstration incubator scheduled for completion at its Hawaii island campus by December.

The energy lab, a state entity, said about 30 percent of the incubator space is committed to tenants with leases being finalized.

NELHA has been working on the addition for several years. The $5.3 million project involves renovating and converting the authority’s former administration building into 10,000 square feet of leasable office space plus collaboration and meeting areas, a conference room and an outdoor lanai.

NELHA received $3 million from the U.S. Economic Development Administration in 2012. The funding balance is from the state and the authority, which operates the 870-acre research and business park supplied with cold deep-ocean seawater in Kailua-Kona.

The state has invested more than $100 million in the park since 1974. Existing tenants include Royal Hawaiian Sea Farms, Cyanotech, Mera Pharmaceuticals, The Marine Mammal Center, desalinated seawater bottler Koyo USA Corp. and Makai Ocean Engineering.