Good World Changing Article on saving energy, using technologies we have - some decades old:

The world is ripe with efficiency opportunities. ("The low-hanging fruit," as Lovins puts it, "is mushing up around our ankles.") His Rocky Mountain Institute points out that in industrial settings, "there are abundant opportunities to save 70% to 90% of the energy and cost for lighting, fan, and pump systems; 50% for electric motors; and 60% in areas such as heating, cooling, office equipment, and appliances." In general, up to 75% of the electricity used in the U.S. today could be saved with efficiency measures that cost less than the electricity itself.

The post goes into how the incentives to adopt these measures, just aren't there - energy costs still are a low percent of overall costs, even at 70%.

If this becomes a priority, regulation would have to be adopted, for this to happen.