From WFPL's Kristin Espeland: Local office building tenants and managers will be competing with each other to see who can improve energy efficiency the most within one year. It’s part of the city’s new "Kilowatt Crackdown" program, kicked off on this Earth Day. Participants will use the federal Energy Star software program called "Portfolio Manager" to track energy usage throughout their buildings.Humana has asked all of its facilities to participate. Spokesman David Noltemeyer says the software should make that easy for any of their locations."All they need is their utility bills, their occupancy rates in their buildings, several steps they have to go through. But in the end it will actually give them a rating of their buildings. It’s actually compensated for weather, so whatever the weather is, wherever our buildings are at, we can actually compare against our own portfolio, or we can compare against like facilities in other states," Noltemeyer said.An Energy Star spokeswoman says that most buildings waste 30 to 40 percent of the electricity they use. The causes include inefficient heating and cooling, and leaving lights and computers on. The city will announce winners after a year.