A coalition of states backing the Paris climate change agreement said it is the third-largest economy in the world after North Carolina joined the group Wednesday in defiance of President Trump's decision to exit the United Nations pact.

"We represent 40 percent of the [U.S.'s] entire economic opportunity," Gov. Jay Inslee of Washington state said to emphasize the seriousness of the coalition's commitment to the Paris deal. "If we were a country, we would be the third-largest economy of any nation in the world."

"We just don't have our own flag," Inslee quipped. He joked that they have no plans to secede.

The U.S. Climate Alliance, the name of the coalition, increased to 15 states with the addition of North Carolina, New York Gov. Andrew Cuomo announced at a press conference on the states' efforts to meet the agreement.

The alliance, which includes the economic behemoth of California — which by itself is the sixth largest economy in the world — represent at least $7 trillion of economic activity and more than 36 percent of the nation's population.

Before North Carolina joined, the 14 states represented about $7.1 trillion, according to the alliance. Now, based on Inslee's estimate of 40 percent of the nation's economy, the alliance now represents about $7.4 trillion of gross domestic product. That is based on the U.S.'s 2016 GDP of $18.6 trillion.

North Carolina is home to the largest coal utility company in the country, Duke Energy, which is also one of the largest utility companies in the world. The company is moving away from coal by transitioning to more natural gas-fired power plants, solar and other forms of renewable energy. North Carolina is the second largest state for solar energy in the country after California.

The company's reach covers a broad swath of the Southeast, even extending into Senate Majority Leader Sen. Mitch McConnell's home state of Kentucky, where it is building three large solar power plants in the heart of coal country.

"Our customers want solar," said Jim Henning, president of Duke Energy's Ohio and Kentucky division, in announcing the new solar power projects in July. The solar power stations are slated to open toward the end of 2017.

The three projects will include 19,000 solar panels spread across 170 acres in Kenton and Grant counties.

Henning said it's the "right time" to build solar because the cost "has come down significantly in recent years, making it more cost-competitive with other sources of power generation." In addition, solar "gives us the ability to add power capacity in incremental steps – allowing us to match the growing demand for electricity in the region."