Peabody Energy Corp., the U.S. coal producer planning to double Australian exports over the next five years, said the country will likely contribute 30 percent to 40 percent of future earnings.

Australia's share of Peabody profit may be at that level "in the next couple of years" and will likely increase as the coal producer seeks "a balanced portfolio" of assets in the country and the U.S., CEO Gregory Boyce said in Sydney on Friday.

Australia's government plans to introduce laws aimed at reducing carbon emissions, with legislation, blocked in August, due to go before lawmakers for a second vote this month. St. Louis-based Peabody has been in "very active discussions" with the government over the proposed system's design, Boyce said.

The carbon pollution reduction scheme, in its original form, "no question, will have a significant impact on coal leaving Australia," he said. "It's going to impose a significant cost."

Prime Minister Kevin Rudd wants carbon trading to start in 2011 to help reduce greenhouse gases by 5 percent to 15 percent from their 2000 level within 10 years. He plans to increase that goal to 25 percent provided a global agreement is reached.

"Our concern is, let's make sure an export industry that has been so critical to Australia's competitiveness and growth over the last 100 years remains that way for another 100 years," Boyce said.

Peabody plans to sell between 21 million and 23 million metric tons of coal in Australia this year, the company said last month.

For 2010, Peabody estimates it will sell as much as 27 million tons of coal in Australia, fueled by demand in Asia.