OPEC’s biggest crude producer is embarking on a domestic renewable-energy program costing $30 billion to $50 billion. The country’s only solar plant in operation, aside from a limited pilot project, is a 10-megawatt facility on top of a parking lot at Saudi Aramco’s headquarters. The national utility, Saudi Electricity Co., is seeking bids for two solar plants to generate a combined 100 megawatts.

We expect global GDP to more than double over the next 20 years, while energy demand increases by only 30%. The difference between those two things is improving energy efficiency or declining energy intensity. That is critical in underpinning the shift we expect to see in the rate of growth of carbon emissions. We think the energy intensity of GDP will decline much more rapidly than we’ve ever seen before.

The U.S. and Mexico will commit to joining Canada in boosting their use of wind, solar and other carbon-free sources of electricity, helping North America meet an ambitious goal of generating at least 50 percent of its energy from “clean” sources by 2025.