Honolulu-based Hoku Corp. says it might have to buy as much as 500 metric tons of polysilicon in the open market to fulfill contracts with its customers because the company has not been able to produce any of the material at its long-delayed factory under construction in Idaho.

Hoku officials said in a regulatory filing that the company is in the process of "commissioning" the $700 million plant, but they gave no firm date for when the company would begin delivering its first shipments of polysilicon, the main component in photovoltaic solar panels.

Hoku has received deposits from six customers for polysilicon shipments totaling $140 million. Failure of Hoku to supply the polysilicon by the stated delivery dates would give the customers the right to terminate the contracts and have their deposits refunded, the company said in a document filed Friday with the Securities and Exchange Commission. Hoku already has refunded $220,000 for missing delivery dates for some of the contracts.

To meet its obligation to customers, Hoku said it is considering buying polysilicon in the spot market.

"During fiscal 2012, the company estimates that it may need to purchase between 300 to 500 metric tons of polysilicon to meet the minimum delivery requirements of its polysilicon contracts," the company said in the filing. The 2012 fiscal year ends March 31, 2012.

With the market price for polysilicon running about $34,000 a metric ton, it would cost Hoku anywhere from $10.2 million to $17 million to buy the material to supply to its customers. Hoku said the arrangement could result in a loss for the company because the amount it would have to pay for the polysilicon could end up being more than what it receives in revenue from its customers.

Falling polysilicon prices have raised questions about the potential cash flow from the plant, Hoku officials said. Hoku based its projections on an average price of $40,000 a metric ton over the 30-year life of the plant. However, the market price dropped to $34,000 a metric ton in November. The company is updating its discounted cash-flow model to take into account the lower prices.

Hoku also said it needs to raise at least $162.8 million more in financing to complete the $700 million plant in Pocatello. Company officials said they anticipate raising cash during the next year through a combination of debt and equity offerings, and possibly new customer contracts.