Two years after Greenpeace slammed Apple for using dirty energy to power its cloud data, the environmental group has praised the company for its usage of renewable energy in maintaining its datacenters, calling it the most innovative and most aggressive firm in Silicon Valley in terms of using clean power. Apples datacenters scored 100 percent in Greenpeaces clean energy index, with none of their energy coming from coal, nuclear, or natural gas sources. The company was awarded A ranks in energy transparency, deployment and advocacy, and commitment, scoring a B rank in its energy efficiency. Facebook also scored three As and a B, but had a lower clean energy index of 49 percent, while Microsoft received Cs across the board and a 29 percent clean energy index.