Solar power systems are getting bigger, better over time

What they did: The annual Lawrence Berkeley National Laboratory analysis explores distributed systems — the stuff installed at homes and businesses, as opposed to centralized utility-scale projects.

Where it stands: One conclusion is that system sizes have been growing and getting more efficient. In the residential sector, the median system has nearly tripled this century to 6.4 kilowatts as of last year.

• "Those trends partly reflect increasing module efficiencies, as many residential systems are space-constrained based on available roof area," they note.

In the commercial and industrial space, the median system went from 7 kilowatts in 2000 to 47 kilowatts in 2018.

• Larger systems have become more common as "a broader set of non-residential customers become comfortable with the technology and as developers and investors seek out projects offering higher returns."

Go deeper:

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• Southern states lead 2019's stock market solar rally