Hoku Scientific Inc., the Honolulu-based clean energy technology company, said it has agreed to an amended supply contract with Jiangxi Jinko Solar Co. that lowers the amount of polysilicon it potentially can sell to the China-based company.

It said Jinko, formerly known as Jiangxi Kinko Energy Co., now will buy up to $178 million of polysilicon from a plant Hoku is building in Idaho. Previously the contract called for buying as much as $298 million.

The amended agreement also calls for Jinko to provide discounted water manufacturing services to Hoku.