Solar Through the Roof

Deck: 

Home solar remains at one tenth of one percent

Today in Fortnightly
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The latest Energy Department data reports that home solar roofs generated 5,111 thousand megawatt-hours during the first ten months of last year.  This represents a 42% increase over the first ten months of the prior year, a hefty gain.

Yet, home solar roofs still contribute less than half of all the megawatt-hours produced by distributed solar.  And the power made by home solar is dwarfed by that made by utility scale solar that is four times greater (by more if solar thermal is included) and by utility scale wind that is thirty times greater.  

Home solar production did rise 42% as we said, from 2014 to 2015, but that increase was from a very small base.  The annual rise was 1,498 thousand megawatt-hours.  The annual rise of utility-scale solar production was 6,920 megawatt-hours, nearly five times greater than that of home solar (again, by more if solar thermal is included).

In the latest month for which the data is available, October 2015, all the hundreds of thousands of home solar roofs nationwide, in total, produced 714 megawatt-hours per hour.  Two typical natural gas combined cycle units produce more power than that.  

October isn't the sunniest month.  Home solar production actually established its all-time record high in August 2015, when all the solar roofs combined to make 848 megawatt-hours per hour.  Two typical gas combined cycle units often produce more power than that.        

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Speaking of natural gas power plants, they generated 1,121,352 thousand megawatt-hours during the first ten months of last year.  This amount is 219 times the generation from home solar.  Both increased their contribution to our electricity supply from 2014 to 2015, but the increased production from gas was 114 times greater than the increased production from home solar. 

As a consequence, the share of the nation's electricity pie claimed by home solar remains at one tenth of one percent.  The share claimed by utility-scale solar is now six tenths of a percent.  The share by wind is well over four percent.  So home solar is growing but it still plays a barely measurable role in powering our society. 

Starting with the February issue, Public Utilities Fortnightly will exclusively present such insightful measures of the electric and gas utilities industry, in our new Mega-Metrics centerfold. 

Steve Mitnick, Editor-in-Chief, Public Utilities Fortnightly
E-mail me: mitnick@fortnightly.com