<http://schema.org/about>
"Even with doubling renewable energy investment over the next decade, and a near tripling by 2030, just over 15% of energy use will come from clean sources."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/energy-policy/renewable-energy-investment-double-2020-one-third-whats-needed.html>