Environmentalists and Portland Mayor Michael Brennan are releasing a report about the growth of solar power in American cities.

Environment Maine is unveiling the report, “Shining Cities: At the Forefront of America’s Solar Energy Revolution,” on Tuesday at 11 a.m. outside of Becky’s Diner near Portland’s waterfront. The group says the report is a comparative look at the solar power growth in cities around the country, including Portland.

The group will also make recommendations for Portland and Maine officials about the city and state’s solar energy policies. The group’s director said it chose to hold the event outside the diner because it has a solar hot-water system.