China-based Suntech Power Holdings Co Ltd said it would close its only solar panel-making plant in the United States to cut costs, two years after opening the facility that never reached full production.

Shares of the company, struggling to cover a convertible bond due this Friday, fell 9 percent to $1.05, their lowest in more than two months.

Suntech opened the plant in Goodyear, Arizona in September 2010, saying that making panels in the United States would reduce time, costs and greenhouse gas emissions related to sourcing panels from overseas.

The plant, however, has been weighed down by U.S. import tariffs on solar cells and aluminum frames as well as a global panel oversupply.

Suntech is required to pay duties of 35.97 percent on solar cells imported from China and used in the plant, the company said on Tuesday.

The plant, originally expected to scale up to 120 megawatts (MW) per year, was scaled down to 15 MW in November.

The closure, slated for April 3, will affect 43 employees, the company said. Suntech had 17,693 employees as of December 2011, the latest period for which job data is available.