Solar energy has undoubtedly become one of the most-talked about sources of renewable energy. Solar panel prices have dropped nearly 70 percent since 2014, and more states have passed laws mandating greater adoption of renewable energy. Solar energy usage in particular is expected to accelerate over the next few decades, and could grow 8 percent per year between now and 2050.
Although there are many state and federal incentives for switching to solar, the landscape for solar energy isn’t identical across the country. State-to-state variations in weather, tax breaks, and power utility structure create a patchwork of opportunities. For the average customer, the decision of whether to install solar is a uniquely personal one. It depends on what they can afford and what options are available in their area. That said, it's important to explore localized patterns in addition to nationwide trends.
Using location-specific solar energy production data and local energy prices, we calculated where individuals and businesses could generate the most solar power and save the most money by installing solar panels. We also mapped the fastest-growing solar cities that are leading the nation in solar installations.
Key Findings
- Across the country, currently only 1.2 percent of buildings suitable for solar have panels installed, though about 81 percent of buildings are qualified.
- Switching to solar energy could reduce utility costs for millions of Americans. The potential annual savings for one building in the U.S. is $1,404. Residents and business owners in Hawaii, California, and Arizona could save the most money by switching to solar energy.
- If all of the qualified buildings in the U.S. switched to solar, it would offset nearly 659 million metric tons of carbon. This would be akin to taking 142 million cars off the road for a year.
- Cities like Houston, Texas, Phoenix, Arizona, San Antonio, Texas, and Chicago could have the greatest environmental impact if all of their suitable buildings had solar panels.
Table of Contents
- Top States and Cities for Solar Adoption
- Leading Solar City in Each State
- States With Greatest Energy Savings Potential
- Cities With Greatest Potential for Carbon Reduction
Top States and Cities for Solar Adoption
Based on data we analyzed from Google’s Project Sunroof, a staggering 81 percent of residential and commercial buildings across the country are suitable for solar panel installations. However, just about 1 percent of these buildings currently have solar installations, though there is a wide range of installations nationwide.
The solar adoption front-runners are primarily in the Southwest and Pacific regions. States such as Hawaii, California, and Colorado have the highest rates of solar power usage. This means that a high percentage of buildings that are suitable for solar have solar panels installed.
Top 10 States for Solar Adoption
| State Name | Percent of Qualified Buildings With Solar |
|---|---|
| Hawaii | 12.10% |
| California | 3.80% |
| Colorado | 2.40% |
| Arizona | 2.30% |
| Nevada | 2.30% |
| Florida | 2.00% |
| Massachusetts | 1.50% |
| Oregon | 1.10% |
| Louisiana | 1.10% |
| New Mexico | 1.00% |
A clear common thread runs through most of the leading states: These are the most well-known sunniest states. Florida and Hawaii have a great deal of direct sunlight throughout the year, thanks to being close to the equator. The Southwest states also benefit from having dry climates. Since they have low rainfall, they also have fewer sun-blocking clouds. Additionally, several of the leading states incentivize solar installations through public policy.
Take Massachusetts, for example. While the Northern state isn’t known for its warm or sunny climate, it still managed to rank in the top 10 for solar power adoption. Massachusetts’ public policies regarding solar are often considered among the best in the country. The state boasts a 15 percent state solar tax credit for home solar systems, a solar power loan program, and direct compensation for solar energy system owners based on how much power they generate. This state’s public policy has been designed to ensure that the decision to install solar is a profitable one for its citizens.
Cities With Highest Rates of Solar Installations
| City | Percent of Qualified Buildings With Solar |
|---|---|
| Heeia, Hawaii | 25% |
| Kailua, Hawaii | 25% |
| Kapolei, Hawaii | 20% |
| Waimalu, Hawaii | 18% |
| Alamo, California | 18% |
| Rotonda West, Florida | 17% |
| Mililani, Hawaii | 17% |
| Jamul, California | 16% |
| Granite Hills, California | 16% |
| Loyola, California | 16% |
| Ladera Ranch, California | 16% |
| Portola Valley, California | 15% |
| Florence, Arizona | 15% |
| Kentfield, California | 15% |
| Fort Bliss, Texas | 15% |
Note: This table reflects cities with at least 500 qualified buildings.
Many of these leading cities are located in Hawaii and California, where some cities enjoy both great weather and supportive local policies. This has led to higher- than-average solar adoption rates. The state of California pays owners of solar panels for the extra energy they generate and send back to the power grid via net metering policies. Hawaii offers a tax credit that pays for 35 percent of the costs of a newly-installed residential solar system. Tax credits like that could help make residential solar systems, which typically range from $10,000 up to $22,000, more affordable for American families.
Leading Solar City in Each State
We noticed tremendous variation in the state-leading cities across the map. In Hawaii’s leading city, Heeia, there are solar panels on about a quarter of its eligible buildings, while South Dakota’s most solar city, Rapid Valley, had solar panels on just 0.1 percent of eligible buildings.
A few critical conclusions can be drawn from this information. First, the leading city for solar energy in each state can and should be considered an example of what can happen when public policies favor rooftop solar.
Some states are large and varied enough in geography that you can’t necessarily expect the same results across the state (such as the differences in Northern and Southern California). Other states, like Maryland, are small and uniform enough that the leading solar cities can serve as the roadmap for the rest of the state. Cities with lower solar adoption should look into what their neighbors are doing to learn what’s possible. Educational efforts and increased local rebates could make a huge difference in increasing solar adoption across states.
Second, certain states and regions may simply not have as much incentive to install solar, regardless of the policies put in place. In some states, low adoption isn’t a sign of ineffective government policy. A state’s population and climate may not be conducive to solar, or there may not be enough urban infrastructure to connect solar panels to the power grid. This explains why states with similar amounts of sunlight, such as Alaska, the Dakotas, and Massachusetts, aren’t equal when it comes to solar adoption. Massachusetts’ cities are more densely populated and have more infrastructure than the remote towns of North Dakota.
States With Greatest Energy Savings Potential
A solar panel installation can cost over $20,000 for a home, and several million dollars for a commercial installation. Though this price tag is steep at first glance, the amount you can save over time on your electric bills can offset the initial costs of solar panels.
To find out how much Americans could save each year by switching to solar, we cross-referenced solar power generation data from Project Sunroof with state energy rates from the U.S. Energy Information Administration. Our analysis includes energy rates for residential, commercial, and industrial buildings.
We found that the energy savings in some states could quickly offset the price of solar installations. Solar panels on the average building would generate about $1,404 a year in energy bill savings, which could be recouped in about 11 years for a $15,000 solar system. In the case of California or Hawaii, however, it wouldn’t take nearly as long to see a return on a solar panel investment. This is because they have abundant sunshine and high traditional energy costs. In fact, energy in Hawaii is more expensive than in any other state, so these residents would have the most to gain by switching to solar.
Top 10 States for Solar Energy Savings Potential
| State | Average Annual Energy Bill-Savings Potential |
|---|---|
| Hawaii | $6,778 |
| California | $3,136 |
| Arizona | $2,488 |
| Florida | $2,120 |
| New Mexico | $1,783 |
| Connecticut | $1,714 |
| Vermont | $1,636 |
| Nevada | $1,585 |
| Rhode Island | $1,580 |
| Mississippi | $1,554 |
Many of the states with high electric bill savings potential are those with high energy costs, such as Hawaii, Connecticut, Vermont, and Rhode Island. The Northern states face higher energy prices than other regions because they are located at the end of the natural gas pipeline. Hawaii’s costs are driven up by expensive imported energy (like natural gas). Some of these states also experience extremely cold weather and winter storms, which place additional demand on energy supplies. If more consumers and businesses in the New England region could install solar panels, their energy costs could be significantly reduced, and the pressure on existing energy infrastructure would be lightened.
Notably, some states with high savings potential and sunny climates (Mississippi, Alabama) have extremely low solar adoption rates. These states also rank in the bottom quarter of states by per capita income. Even though solar energy could potentially save families a lot of money, coming up with the upfront capital or qualifying for the necessary financing for a solar energy system can be impossible for many people. These challenges increase the need for equity in solar energy programs because low-income households are also the ones that would benefit most from energy bill savings.
Cities With Greatest Potential for Carbon Reduction
One of the greatest benefits of using renewable energy like solar is that it is much better for the environment. For local and state governments across the country, reducing emissions of greenhouse gas has become a top priority as they look to stave off the impacts of climate change. If cities and towns can rely less on fossil fuels and more on renewable energies like solar, they can collectively reduce their carbon footprint.
If all of the qualified buildings in the U.S. switched to solar, 659 million metric tons of carbon would be offset, which would have significant environmental impacts. Reducing greenhouse gas emissions would slow the impacts of climate change, which has resulted in increasing fires, droughts, and storms. Further, increased reliance on energy sources like solar can reduce smog and other air pollutants, which is critical for community health.
Top 10 Cities With Greatest Carbon Offset Potential
| City and State | Potential Carbon Offset in Metric Tons |
|---|---|
| Houston, Texas | 8,921,452 |
| Phoenix, Arizona | 6,388,564 |
| San Antonio, Texas | 5,822,687 |
| Chicago, Illinois | 5,520,256 |
| New York, New York | 5,516,961 |
| Indianapolis, Indiana | 5,189,260 |
| Oklahoma City, Oklahoma | 4,847,819 |
| Los Angeles, California | 4,213,030 |
| Memphis, Tennessee | 4,212,251 |
| Jacksonville, Florida | 4,198,470 |
| Columbus, Ohio | 4,163,977 |
The massive metropolis of Houston, Texas, leads the nation in carbon-offset potential, but it can be difficult to conceptualize the true impact of removing 8.9 million metric tons of carbon from the atmosphere. According to the U.S. Environmental Protection Agency, the 8.9 million metric tons of carbon that Houston can reduce via solar panels on buildings is equivalent to:
- 1.9 million cars taken off the road for one year
- The carbon output from 1.7 million homes’ worth of electricity
- 2.4 entire coal-fired power plants running for one year
- 2,419 wind turbines running for one year
- 10.5 million acres of U.S. forest sequestering carbon for one year
Put another way, these aren’t trivial results. Solar can go quite a long way towards reaching our nation’s climate goals. For the everyday person, this amount of carbon reduction can result in reduced risk to respiratory ailments, decreased likelihood of the health risks from excess heat, and reduced weather-related morbidity and mortality. For a city or state government, this could mean reduced spending on weather-related disasters. Weather disasters cost the U.S. $145 billion in 2021 alone. Further, for every new source of solar generation connected to the grid, the polluting impacts of local fossil fuel generation will decrease. These pollutants are known to result in airborne toxins, respiratory issues, brain damage, heart problems, cancer, and more.
Conclusion
In the effort to increase our use of clean energy and decrease reliance on fossil fuels, solar energy is one of the most readily available tools that doesn’t need a lot of space or infrastructure. These advantages are why solar installations are the focus in cities across America.
But the data indeed shows some states and cities are adopting solar energy more quickly than others. Some of these states are leading the solar race due to factors that cannot be controlled (weather, geography). Others are taking action to make sure their citizens reap the benefits via favorable solar public policies.
On an individual level, solar panels not only benefit the power grid and the climate, they bring economic benefits in the form of reliable energy savings to homeowners and businesses that invest in them. States and cities should consider emulating the public policies of national solar leaders to allow their citizens to reap the same rewards. This is particularly important as the upfront costs can still be challenging to overcome for some.
Methodology
For this project, we accessed Google’s Project Sunroof data in March 2022. This comprehensive database estimates the suitability of buildings for solar panel installations using Google Maps. This database covers approximately 83 percent of buildings across the country. It also tracks the number of buildings with solar panels installed. We combined data on the number of kilowatt hours of sunlight generated in each city from Project Sunroof with 2020 state energy cost data from the U.S. Energy Information Administration. With these data, we were able to estimate the potential energy cost savings by state.
We multiplied each state’s average energy cost (dollars per kWh hour) by the amount of solar energy that could be generated by the qualified buildings each year in kWh hours. This gave us the potential annual energy cost savings. We also calculated the yearly sunlight kWh of the median building to get the potential annual energy savings for a typical building. Our data was limited because we could not calculate savings for residential, commercial or industrial buildings separately. There is a great range in the energy costs and usage between these types of buildings.
For our analysis, we did not include cities with fewer than 500 solar-qualified buildings in our calculations.