Are you a good data sleuth? here is a puzzle. Yes, California has a temperate climate that doesn't require much air conditioning but take a close look at this picture below. Note the "divergence big time" between California's per-capita electricity consumption relative to the rest of the nation. Who gets credit for this green progress? The de-industrialization of California? Effective energy policy? New capital investments by for profits minimizing expected PDV of electricity bills? All? Neither?
A new Stanford paper takes a look at this important issue. Jim Sweeney's Paper . Sudarshan and Sweeney give policy 20% of the credit. That appears to be smaller than the conventional wisdom.
Here is another picture that I like. I see the power of liberal ideology. From this graph you can't tell if this power is from a displacement effect such that energy intensive activity migrates away from these states or if environmentalist states are able to "treat" energy intensive activity to reduce its energy intensity.