In the fallout of the recent solar import tariffs announced by the Trump administration, a point of optimism has arisen from a dozen cities with notable growth in solar installations over the past 12 months.

According to Ohm Analytics’ Q4 2017 Solar Index report, Las Vegas and Miami topped a list of the 15 fastest growing cities last year. Houston, Philadelphia and Portland round off the top five.

The list is based on permit data for commercial and residential installations. Utility scale solar is not included.

Ohm Analytics attributes a number of factors to the growth. For example, it finds the re-instatement of net metering in Nevada fueled a major resurgence of installations in Las Vegas. Similarly, reduced taxes on solar installations in Florida opened the market in Miami.

The research firm also finds that one or two factors can just as easily lead to negative growth in some states. For example, it asserts that a change in net metering combined with a change in sales strategy by Solar City owner Tesla led to a 27 percent decline in the solar market in most of the major cities in California, the state with the nation's largest solar market.

However, its capital city was not subject to these changes, and the market has responded. Sacramento occupies the 14th spot on the Ohm Analytics list, with just over 6,000 installations, for an annual growth rate of about 5 percent.

While overall rooftop solar activity declined 14 percent in 2017 from 2016, Ohm finds that the growth in some cities is an otherwise positive sign. It notes that, while cities in the nation's top solar producing states—California, Hawaii, Massachusetts and Maryland—are mostly absent from the list, other cities from traditionally fossil-fuel burning states, like Pennsylvania and Texas, have taken their place.

The cities of Austin, TX; El Paso, TX; Fort Collins, Colo.; Pittsburgh, Pa.; Salt Lake City; Denver; Seattle; New York; Sacramento, Calif.; and Phoenix occupy the final 10 spots on the list.