It's day three of President Obama's trip to the Golden State.

Today, he's appearing at a Walmart in northern California to talk about advances in energy efficiency. He's expected to talk about commitments from more than 300 companies as well as local and state governments to use solar energy technology.

The president will also announce executive actions aimed at increasing energy efficiency in buildings and appliances. For more on this we turn now to James Sweeney, director of the Precourt Energy Efficiency Center at Stanford.