(Reuters) - U.S. solar manufacturers on Tuesday asked federal trade officials to impose tariffs on cheap foreign-made panels, clashing with companies who rely on those products to build low-priced projects that can compete with gas and coal.

Solar panels are pictured on the rooftops of residential homes in San Diego, California August 21, 2015. REUTERS/Mike Blake

In a closely-watched case, the U.S. International Trade Commission is set to recommend measures to prop up the small domestic solar manufacturing industry after it ruled unanimously last month that producers have been harmed by imports.

It must deliver its report by Nov.13 to President Donald Trump, who will then decide how to proceed.

The outcome could have a major impact on the price of solar power in the United States and determine whether the renewable energy technology can compete with dominant fossil fuels.

Suniva and SolarWorld, which are both foreign-owned but manufacture panels in the United States, asked for four years of tariffs on all solar cells and panels made overseas, plus either a price floor on panels or an import quota.

“Tariffs alone will not remedy the serious injury you found,” Suniva attorney Matthew McConkey told the commission.

In documents filed last week, Suniva asked for a tariff of 25 cents per watt on solar cells and 32 cents per watt on panels. The manufacturer is also seeking a minimum price on panels of 74 cents a watt, nearly double their current cost. SolarWorld has asked for an import quota.

Existing tariffs on solar products from China and Taiwan have been insufficient to protect the domestic industry, Suniva said.

Suniva is majority owned by Shunfeng International Clean Energy and SolarWorld AG is based in Germany. Suniva filed for bankruptcy in April and soon after filed its petition with the ITC.

The Solar Energy Industries Association, the sector’s primary trade group, opposes Suniva’s petition.

SEIA argued on Tuesday that higher panel prices would hurt demand, impacting installation companies and manufacturers and leading to widespread job losses.

“These job losses are far, far in excess of any limited job gains the domestic cell and module industry might obtain based on optimistic projections,” SEIA attorney Matthew Nicely said.

SEIA suggested less radical remedies - technical assistance, job training programs, and a modest import licensing fee.

SunPower Corp Chief Executive Tom Werner testified that concerns about new tariffs had caused his company to lose “a multi-hundred million dollar opportunity” to rival First Solar Inc, which uses a technology not included in the trade case.

“We couldn’t offer price certainty and they could,” Werner said. SunPower is based in California but primarily manufactures panels in Asia.