Here is a bit of interesting info that the U.S. Energy Information Association posted today. According to them, University of Phoenix Stadium, home of Super Bowl XLIX, replaced more than 780 metal halide high-intensity discharge fixtures with 312 highly energy efficient LED stadium fixtures before the start of the 2014 NFL season.
From the EIA:
University of Phoenix Stadium was the first stadium in the NFL to light its playing field using only LEDs. The new lights draw approximately 310 kilowatts of energy compared with the 1,240 kilowatts required by the old system, a savings of about 75%. Assuming an electricity cost of 15 cents per kilowatthour, that means the new LED lighting costs about $47 per hour to light the field, compared to $186 per hour using the HID lighting system. Lighting maintenance costs for LEDs are also expected to be lower. The vendor also projects a 30% decrease in stadium cooling costs as a result of the LED fixtures, which generate less heat than HID lights.
Read more here.