The United States was a net exporter of solar energy products last year, thanks to strong demand from China, Germany and Japan for U.S.-made polysilicon and capital equipment used to make solar panels.

U.S. photovoltaic-related exports totaled $5.6 billion in 2010, compared with imports of $3.7 billion, according to a study by GTM Research prepared for the Solar Energy Industries Association, a U.S. trade group.

Exports of polysilicon, the solar industry's key raw material, were $2.5 billion last year. Capital equipment exports totaled $1.4 billion.

The top three destinations for U.S. solar products were China, Germany and Japan. The U.S. solar industry was a net exporter to China of $247 million to $540 million.

The United States was a net importer of the modules that transform sunlight into electricity. Modules were the nation's most imported photovoltaic product, accounting for $2.4 billion. The United States exported just $1.2 billion of modules.

Imports came mostly from China, which accounted for $1.4 billion of the total. Mexico was a distant second at $480 million.