MINNEAPOLIS — When city leaders and state legislators agreed last year to fund roughly half the $1 billion cost of a new stadium for the Minnesota Vikings, they attached the usual strings for such projects: It had to be architecturally iconic, employ steel made from Minnesota iron ore and offer at least a few cheap seats.

It also had to be energy efficient, from lighting to building materials to the sources of its power. In this state, that is not unusual. Minnesota has mandated sharp reductions in energy use in every new state-financed building for more than a decade, and in renovated buildings for more than five years.

While other states and critics of the Obama administration have howled about complying with its proposed rule slashing greenhouse gas emissions from power plants, Minnesota has been reining in its utilities’ carbon pollution for decades — not painlessly, but without breaking much of a sweat, either.

Today, Minnesota gets more of its power from wind than all but four other states, and the amount of coal burned at power plants has dropped by more than a third from its 2003 peak. And while electricity consumption per person has been slowly falling nationwide for the last five years, Minnesota’s decline is steeper than the average.