National Geographic: Earlier this week, India—the world’s fourth largest energy consumer—experienced massive power outages unprecedented in their duration and geographic extent. Monday’s outage lasted 15 hours, only to be followed by another on Tuesday, during which more than 600 million people across the country lost electricity. Although the root causes of the outages have yet to be determined, it is well known that India is facing a major energy challenge. With its economy growing at a rate of about 9% annually and its per capita energy consumption expected to double by 2020, India needs to generate more power more efficiently. With its two main power sources, nuclear and coal, facing public opposition and spiraling costs, some experts have urged the country to focus more on renewable energy such as solar and wind.