If San Diego goes for smaller solar, it could yield huge results

A recent solar siting survey conducted by The Clean Coalition found that San Diego has huge potential for solar development, and that the number grows sharply when smaller sites are considered.

January 16, 2019 Tim Sylvia

Image: John Bahu for the California Travel & Tourism Commission

We’ve all heard it: less is more, but just as often as we hear it is it inaccurate. However there are situations where it holds true, namely in painful endeavors like debt and golf.

However, according to a study conducted by the Clean Coalition for the City of San Diego, as part of the National Renewable Energy Labratory’s Solar Energy Innovation Network program, the city of San Diego could maximize its solar potential by adopting this mantra.

The reasoning all comes down to project size. The survey’s official mark for growth estimates 500 MWac of untapped solar potential in the city. This potential is dominated by parking lots and parking structures, to the tune of 75% of the over 120 qualified locations. The remaining 25% is comprised mostly of rooftops.

However, the trick is that this is not the sum of San Diego’s potential. It is a conservative estimate of potential assuming a minimum project capacity of 1 MWac, which if quite large for distributed solar. The Coalition must have realized this too, as the survey was expanded upon to include much smaller minimum project sizes. For example, if the minimum capacity were reduced to 500 kW, the siting potential o the city would immediately double to 1 GW.

1 GW is a lot of potential, but it gets better.

If the minimum project size was reduced to 100 kW, we would again see the siting potential double to 2 GW, a truly incredible mark. 2 GW is where The Coalition’s estimation stops, but that’s not the full story. See, that number really doesn’t account for all distributed solar. 100 kW is still quite large for an installation; for reference, it’s generally accepted that the average rooftop solar installation is in the 5-7 kW range.

This was not an accidental oversight. The report recognizes that the cutoff is high, referencing that large projects are more cost-efficient than smaller projects and increase the potential to attract developers and investors.

And it should still be noted how impressive it is that San Diego has over 120 untapped sites that are all capable of hosting at least 1 MW projects.

A summary of the report can be found here, while a spreadsheet of the survey data can be found here and finally, the survey’s Google Earth file.

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