China's cost to produce solar panels has plummeted 42% in the last year, according to a report published on Thursday, giving manufacturers there an enormous advantage over rivals in places like the United States and Europe.

The dramatic decline comes as the world's largest solar panel producer has ratcheted up production capacity this year while the United States is incentivizing its own small industry to take on China. U.S. producers are concerned the wave of new factories could make their own uneconomical.

China accounts for 80% of the world's solar manufacturing capacity, according to the analysis by energy research firm Wood Mackenzie shared with Reuters. In a separate analysis last month, Wood Mackenzie said China was expected to dominate the global solar supply chain for much of the next decade.

China's panel production cost has dropped to 15 cents per watt this year, more than 60% below the U.S. price of 40 cents per watt, according to the report. A year ago, Chinese panels cost 26 cents per watt.

Europe's production cost stands at 30 cents per watt, while India's is 22 cents per watt, according to Wood Mackenzie. (Reporting by Nichola Groom; Editing by Sonali Paul)