Efforts are underway to drive down cost of using renewable energy. :
Tesla has reduced prices on its solar power systems as it looks to make sustainable energy use more affordable. "As a result of the vertical integration of our solar products into Tesla's retail stores and the increased efficiencies we've realized over the past year by closing more expensive sales channels like door-to-door sales, we are now able to reduce prices for our solar power systems," a Tesla spokesperson told CNBC in a statement Friday.