Peabody says the campaign highlights “the vital role that clean coal plays in keeping St Louis skies blue and energy bills low”

"More than 80% of Missouri's electricity is powered by coal and, in turn, our state's electricity rates are among the lowest in the United States," Boyce said.

“By comparison, Californians pay electricity rates more than 60% greater than those in our state.

"And tremendous progress has been made in improving the emissions profile for coal.

“Since 1970, key emissions rates from US coal plants have decreased 90%, as related coal use has increased 170%."

The St Louis initiative is part of the global "advanced energy for life" campaign, which was launched in February to “end energy poverty” by adopting clean coal to provide affordable energy.

The company has some way to go if it is going to convince St Louis.

This week seven Washington University students were arrested after attempting to enter the uni’s trustee meeting, demanding Boyce resign.

Sit-ins at the university campus in suburban St Louis lasted 16 days and attracted media attention from around the globe.