ARVADA, Colo. – Countries are lining up to supply a huge global market for solar energy, and it’s important for the United States to stay in the game, Energy Secretary Steven Chu said Friday after touring a Colorado solar facility.

Chu’s comments came a day after hostile questioning by Republicans in Congress over Solyndra Inc., the solar panel maker that received a $535 million federal loan guarantee in 2009 but has since gone bankrupt. Chu told a House committee that cheap imports from China, the collapse of the European market for solar panels, and other market changes led prices for Solyndra’s product to fall.

“What happened with Solyndra was truly unfortunate,” Chu told reporters after walking through a PrimeStar Solar Inc. facility that General Electric Co. bought this year.

Few people predicted prices for solar modules would fall 70 percent from 2009 to today, Chu said, and it’s unclear when the price of solar power will fall enough to be comparable to electricity produced using natural gas.

“When solar reaches price parity with any other form of new energy — you know it’s going to happen — it’s going to go viral,” Chu said.

He also said energy storage will be key to solar’s success, so it can serve as an energy source when the sun isn’t shining.

Chu said the worldwide market for solar photovoltaic systems is more than $80 billion. Although the United States developed several solar technologies, China now holds roughly half the market share in solar cell and solar module production while the United States share lags far behind, Chu said.

“It’s very important we stay in this game,” Chu said, adding that high levels of innovation are still happening in the United States.

“We should not wave the white flag. We should not say, ‘Oops, we may have invented it, but we’re going to be out-manufactured.’ But we really can and should take back this technology lead,” Chu said.

PrimeStar Solar Inc., whose Arvada facility Chu toured Friday, was co-founded by researchers associated with the National Renewable Energy Laboratory in Golden. It received $3 million from the Energy Department in 2007 to get thin-film solar panels made from cadmium telluride into commercial production. It also received $25,000 from the Governor’s Energy Office in 2008 to help develop its production facility.

GE has said it plans to build what would be the largest solar factory in the United States in the Denver suburb of Aurora, without federal subsidies.