Extracting clean fuel from sunlight

Securing enough energy to meet human needs is one of the greatest challenges society has ever faced. Previously reliable sources—oil, gas and coal—are degrading air quality, devastating land and ocean and altering the fragile balance of the global climate, through the release of CO2 and other greenhouse gases. Meanwhile, earth's rapidly industrializing population is projected to reach 10 billion by 2050. Clean alternatives are a matter of urgent necessity.