BOULDER, Colo. -- Correction: The original version of this article said that all five people arrested were protesters. In fact, one of the five, Ethan Welty, was at the protest as an independent photojournalist.

Four environmental activists and an independent journalist were arrested Tuesday after the protesters climbed over the fence surrounding an Xcel power plant in Boulder as part of a demonstration against the use of coal.

The protesters climbed a coal pile and unrolled a massive sign reading "Renewables Now." They also set up two mock wind turbines, reported the Boulder Daily Camera.

Boulder sheriffs deputies arrested and charged each with one count of second-degree trespassing. They have been identified as Erik Bonnett, 27, Katherine Clark, 25, Thomas Weis, 47, and Eric Ross, 23. All are from Boulder. A fifth person, Ethan Welty, 23, was identified by police as a protester but Welty said he is an independent journalist who was covering the protest.

"My questionable arrest occurred after theirs, suddenly and unexpectedly, while I was standing in the street by the rally," Welty told 7NEWS on Friday. Welty has a website listed as "Ethan Welty Photography/"

The misdemeanor carries a maximum penalty of six months in jail and a $750 fine.

Sheriff's deputies said about 20 other protesters gathered outside the power plant on 63rd Street to protest the use of coal.

The protesters told the Daily Camera, they wanted the city of Boulder to continue an agreement set to expire in August with Xcel Energy that would set up a larger percentage of renewable energy for the city.

"I came today because I think we should be able to choose where our energy comes from," protester Diana Best told the Camera. "Most people are here in response to the franchise agreement. It should be our choice."

On a Blog post about the demonstration, Weis said "citizens needs to take our energy future into our own hands," if the city does not work with Xcel to generate 100 percent renewable energy.

Link: Photos of the protest