A year of sun in review:

Twelve months ago, just two states — Hawaii and California — had committed to reaching 100 percent renewable energy. But by year’s end, four more — Washington, New Mexico, New York and Maine — had joined their ranks. In addition, more than 150 cities across the country have now either made or already achieved that same visionary goal. 

Spearheaded by youth leaders like Time’s Person of the Year Greta Thunberg, this groundswell of state and local action is reflective of a rise in climate activism in 2019. It was also bolstered by rapid growth in the renewables energy sector nationwide. With the solar industry flourishing, countless new solar projects have come on line since January. All this success merits taking a moment to consider solar energy’s key turning points in 2019.

Like most of our nation’s pivotal social movements, grass roots support is the backbone for solar energy’s success. Recent polls conducted by Pew Research Center show that the vast majority — 92 percent — of Americans support expanding solar power, including strong majorities of both Republicans and Democrats. Buoyed by this support, city officials are leading the way with bold commitments and smart policies that bolster solar energy adoption. Environment America’s Mayors for Solar Energy project, featuring more than 300 mayors who have signed onto a letter in support of solar-powered communities, just goes to show how many local leaders across the country are speaking out. 

In fact, some 50 cities have committed to 100 percent renewable energy since December 2018. To turn their vision into reality, they’re using a wide variety of creative policies. 

For example, more than 300 municipalities have achieved SolSmart designation. This certification is awarded to cities that streamline local permitting processes and other procedures to make it faster, easier and more affordable for local businesses and residents to install solar systems. Cities such as Milwaukee, Wis., Minneapolis, Philadelphia and Ypsilanti, Mich., are also using other tools, like financing programs, group purchasing campaigns and local tax incentives to encourage solar energy adoption.

Policies like these have led to a rooftop solar boom. Of the 57 cities surveyed in all six editions of Environment America’s annual Shining Cities report, 79 percent more than doubled their total installed solar photovoltaic (PV) capacity between 2013 and 2018.

Along with that great progress at the local level, several states have stepped into the solar forefront in 2019. For example, California, having passed a groundbreaking policy requiring solar on all new homes in 2018, reached a monumental milestone of one million installed solar roofs earlier this month. 

A handful of other states also passed sweeping bills to ensure that solar energy continues to not only become increasingly accessible and affordable to residents and businesses but also ultimately provides a growing share of states’ energy mix. Maine, Oregon and South Carolina were among the success stories on that front.

Nevertheless, the year also brought challenges for solar. The debate around how to fairly compensate residents and businesses with rooftop solar panels heated up across the country. As a result, a number of states saw attacks on key programs like net metering, which ensures homeowners with solar receive a fair price for the clean energy they feed into the grid. Thankfully, states such as Montana, Wisconsin and Georgia chose to largely defend and uphold those critical programs. 

But proposals from utilities and special interests won out in several others. In Kentucky, for example, solar adoption is expected to continue to lag as it becomes harder for solar producers to see savings from their clean energy investments. This hot-button issue is likely to continue into 2020 and beyond, as many states are currently taking a hard look at how to value the energy that residents and businesses capture by installing solar. 

That said, the biggest missed opportunity in 2019 came at the federal level. Congress had a prime opportunity to update and extend clean energy tax incentives for everything from solar and wind projects to electric vehicles and energy efficiency investments through tax extenders. Despite vast public support, advocacy from local leaders nationwide and calls for action from within the halls of Congress, these key incentive programs failed to pass — with the exception of a modest extension of the Investment Tax Credit for wind energy projects. 

For all the tremendous ups — and the few downs — for solar energy in 2019, we must now look forward. Our nation is blessed with renewable energy resources plentiful enough to power the entire country several times over. We need to keep increasing the pace at which we are moving toward a renewable energy future. This is necessary in order to ensure a cleaner, healthier planet for generations to come. Leaders at all levels must pitch in and help make that happen. So, this New Year’s Eve, you’ll find me raising a glass full of hope that 2020 proves an even bigger year for solar energy.