A subsidiary of U.S. utility the Ameren Corporation has laid out plans to add "at least" 700 megawatts of wind generation by the year 2020.

In an announcement on Monday, Ameren Missouri said the scheme would be backed by an investment of around $1 billion and that it would also look to add 100 megawatts of solar generation over the next 10 years.

"This is Ameren Missouri's largest-ever commitment to clean, renewable energy," Michael Moehn, Ameren Missouri's president, said in a statement.

"We are committed to bringing our customers innovative solutions that are both cost-effective and environmentally responsible while maintaining the reliability our customers expect," Moehn added.

Ameren Missouri said that the new wind production was expected to be based in Missouri and neighboring states, using "American-made" turbines. The location, source and cost of the new generation was still under negotiation with developers, it added.

"We expect this tremendous growth in wind generation to provide great value to our customers, who will save money on energy costs," Moehn added.

The business also said it was setting itself the goal of slashing its carbon emissions by 80 percent by 2050, compared to 2005 levels. Moehn said that Ameren Missouri was the first investor owned utility in the state – and one of the first in the country – to "announce a carbon emissions goal of this magnitude."

Breaking this goal down further, the company said it was targeting a 35 percent reduction by 2030 and a 50 percent cut by 2040.