Stadiums are big consumers of electricity and producers of waste, but they're trying to clean up their acts. In the last four years Baltimore's M&T Bank Stadium has cut its appetite for electricity by 2 million kilowatt hours — about what 144 average households use in a year. This was thanks in part to replacing the old high definition video board, which required massive air conditioning, with a new system that runs without needing climate control. Installing low-flush toilets, along with other conservation measures, has cut water usage by over 40 percent in the past five years. Even tailgating has gotten greener as the stadium recycling program, which has collected an average of 8 tons per game, has extended to the parking lots, a source of many empty beverage containers.