YORK, Maine — "Do you know why I came here today?" Sen. Angus King, I-Maine, asked a bunch of excited York Middle School students clearly enthralled to have a U.S. senator at their school. "I came because this is really cool."

"This" is a project that intersects what King said are two of his favorite topics — energy and technology — as the ceremonial electricity began to surge from a 40-panel solar array on the school roof to power all the students' laptops.

The panels were installed over the summer, using a competitive $22,278 grant awarded to the school by Efficiency Maine.

Eric Hopkins, of the local group York Goes Green, spearheaded the effort. The panels are expected to generate 12,717 kilowatts of electricity — enough to power all student laptops during the school year.

The visit from King was the centerpiece of a school assembly held to celebrate the startup of the panels' power. As governor, he started the school laptop initiative.

In a talk that was both a science and a civics lesson, King held up a student globe. He said a veneer was put on the globe to prevent the paper from peeling and to make it shine.

"Did you know the atmosphere of the Earth is the same thickness relative to the Earth as the coat of varnish on this globe?" he said. "It's not very thick."

Into that atmosphere, he said, "we're burning oil that took millions of years to make." Yet much of the world's supply has been burned in the past 150 years at power plants and in cars, he said. "I don't think it's fair to burn it all up now. We have to think of the people who come after us.

"We don't own the Earth. We're only borrowing it. And we have to treat it right."

King also spoke to the students about the laptop program, which has benefitted thousands of middle schoolers throughout the state since it was established in 2002.

"Most of the people of Maine didn't want you to get them. They said you couldn't take care of them," he said, to groans from the audience. "You can take care of them, and you have."

He said, however, there are risks that come with that responsibility. "Can you get into trouble online?" he asked.

"Yes," students said.

"It's up to you to be responsible. But I have confidence and faith in you," King said.

Earlier, Hopkins told the students about Cynthia Raymond, a York Goes Green member who was an active member of the group before she died in 2011 at age 98. Hopkins said when he and Raymond started the group in 2007, "she told me, 'Eric, we need to do something about climate change.'"

The solar array is dedicated in Raymond's honor.

Hopkins said he was galvanized by Raymond's words into working toward a project in town, that culminated all these years later in the middle school solar panels. He told the students that they, too, could "do something," even at their ages.

King agreed. The motto of Maine is "Dirigo, I Lead," he said.

"You can lead. There's nothing you can't do. You can go anywhere, be anything. You have such an opportunity to make a difference in this world," he said.