The change has taken Denmark nearly two decades to implement, but the most critical step was the introduction of smart- or net-metering, which required utilities to buy back electricity from consumers at 85% of the price.

FORBES: The Answer To The Energy Problem

However, in districts where there are net metering rules in place, schools could sell excess energy back to the utility and get close to offsetting all of their energy bills.

FORBES: Could Going Solar Save Teacher Salaries?

Smart metering is part of an increasingly popular trend in energy efficiency called "demand response" in which customers voluntarily cut back on their power consumption during times of highest electricity demand, like the hottest days of summer, when air conditioners are running at full blast.

FORBES: Magazine Article