The falling price of renewable energy, efforts to address climate change and the proliferation of Big Data are key trends upending the way the power grid has operated for the last 100 years. The past 240 years saw the industrial revolution shift our use of energy "from horse power to horsepower," he said. Instead of traveling with two horses and a wagon, a car with 300 hp is now taking us to the grocery store, and we can travel across the continent in a plane that’s the equivalent of 100,000 horses. But global economic growth, and the rising global carbon emissions that helped the energy world power that growth, have created challenges and a need to “decarbonize” the energy system at a time when vast parts of the planet still lack electricity, he said. “How can we decarbonize our energy system — which we have to do to address climate change — but still continue the economic growth?” Majumdar said. “Some people think these are mutually exclusive, but it need not be.” The challenges of the years ahead are plentiful, including both the engineering and the policymaking arenas.