A transformer lockout at the Monticello nuclear power plant prompted an automatic shutdown Friday afternoon. Xcel Energy says the malfunction interrupted non-safety-related power, but that all safety systems functioned as designed.

An Xcel Energy spokeswoman says low oil pressure in the plant's turbines triggered an automatic shutdown over the weekend. The company says the safety system functioned as designed and that no one was in danger.

A Minnesota family has just moved into a high-efficiency home billed as the most eco-friendly Habitat has ever built. The University of Minnesota helped design the home and utilities are expected to cost the owner $60 a month.

Xcel Energy says its Monticello nuclear power plant automatically shut down at 11:07 a.m. Tuesday, but officials aren't sure why and a cause is being investigated, the Pioneer Press reports. All plant safety systems were functioning, officials with the Minneapolis-based utility said. The shutdown posed no danger to the public or workers, Xcel officials said. The plant is not expected to be down long.

Two activists from Duluth and an 82-year-old nun were arrested Wednesday and charged with federal trespassing after they allegedly breached a high-security area in a Tennessee complex that stores and processes uranium. A government official said the protesters, who dubbed themselves Transform Now Plowshares, "put themselves at a high risk of losing their life" in the incident.