Where In The Us Is Solar Energy Most Plentiful?

The American Southwest has the most abundant solar resources in the contiguous United States due to its latitude, elevation, and predictable sunny weather. This region harnesses the greatest solar potential and has seen massive growth in solar installations to tap into the bountiful and renewable energy source overhead. While other areas, like the Southeast, hold promise for solar expansion, the Southwest’s inherent advantages make it the leader in productive solar capabilities.

Solar Insolation Map

Solar insolation maps show the amount of solar radiation received in different geographic areas. These maps use solar irradiation data to visualize the average daily, monthly, and annual solar energy available per square meter for different regions.1

Areas with higher solar insolation levels are shown in orange and red on the maps, while areas with lower insolation are shown in green or blue. This allows you to see at a glance which parts of the country have the greatest solar energy potential based on sun exposure.

The Southwest region of the U.S. stands out on solar insulation maps, with states like Arizona, New Mexico, Nevada, and California receiving the most abundant solar radiation. This makes these areas well-suited for solar installations to effectively capture the ample available sunlight.

Southwest Region

The Southwest region of the United States, comprising states like Arizona, New Mexico, and Nevada, has enormous potential for solar energy. According to the Solar Energy Technologies Office, the Southwest region has the highest solar insolation in the country, meaning it receives the most solar radiation. This is due to its unique geographic location and climate

Specifically, the Southwest states are located at lower latitudes and higher elevations compared to other parts of the country. Lower latitudes allow the sun’s rays to strike the Earth more directly, increasing solar radiation. Higher elevations also experience less atmospheric attenuation, meaning less solar radiation is absorbed or scattered by the atmosphere before reaching the ground. According to Solar Energy Planning for the Southwest, Arizona, New Mexico, and Nevada have 30% more solar insolation than average.

The Southwest region also benefits from clear, sunny weather for most of the year. According to the National Renewable Energy Laboratory’s PVWatts calculator, cities like Phoenix, AZ and Las Vegas, NV enjoy solar insolation of 6-7 kWh/m2/day annually. This high and consistent solar resource has led to major investments in solar installations. As of 2021, Arizona ranked 2nd in the nation for installed solar capacity, while Nevada ranked 5th according to Solar Southwest. The Southwest’s solar resource is a major economic advantage for renewable growth.

Latitude and Elevation

The Southwest region of the United States, including states like Arizona, New Mexico, and Nevada, has high solar potential due to its low latitude and high elevation. At lower latitudes, the sun’s rays strike the earth more directly, resulting in greater solar intensity and energy. According to research, “There is less dispersed solar radiation at the equator than there is at more extreme latitudes” (The Potential of Solar Energy at High Altitude Regions – Energy5).

Higher elevations also increase solar potential because there is less atmosphere for the sunlight to pass through before reaching the panels. Studies have found that “solar energy harvesting at high altitudes is more effective than at sea level” due to reduced scattering and absorption of photons (The Efficiency of Solar Power at High Altitudes). Many parts of the Southwest region like Colorado and New Mexico have high plateaus and mountainous areas ideal for capturing solar energy.

Sunny Weather

The American Southwest region benefits from an abundance of sunny, clear days. According to a report by the National Renewable Energy Laboratory (NREL), “the Southwest has the best solar resource in the continental United States” (Brighter than a Hundred Suns: Solar Power for the Southwest). This region receives high solar insolation, which refers to the amount of solar radiation reaching the Earth’s surface. The Southwest’s arid climate features sunny skies for 80-90% of daylight hours annually.

In particular, states like Arizona, New Mexico, Nevada, and California have excellent solar energy potential thanks to minimal cloud cover and precipitation. For instance, Phoenix, Arizona averages sunshine 85% of the time and Tucson averages sunshine 88% of the time (US Solar Energy Potential by Region, Season, and More). The Southwest’s sunny, dry climate provides ideal conditions to generate solar power consistently throughout the year.

Solar Installations

The Southwest region has seen major growth in large-scale solar installations due to the optimal conditions. Some of the largest solar farms in the U.S. are located in the deserts of California and Nevada.

For example, Solar Star is currently the largest solar farm in the U.S. with a capacity of 579 MW. Developed by BHE Renewables, Solar Star is located in Rosamond, California and occupies over 13 square miles of the Mojave Desert (https://www.solarfeeds.com/mag/solar-farms-in-the-usa/).

Other major installations in the Southwest include the 550 MW Desert Sunlight Solar Farm in Riverside County, California and the 250 MW Moapa Southern Paiute Solar Project north of Las Vegas, Nevada. Several large-scale projects are also under construction or planned, like the 690 MW Gemini Solar Project in Clark County, Nevada (https://en.wikipedia.org/wiki/Solar_power_plants_in_the_Mojave_Desert).

In total, the installed solar capacity in the Southwest is expected to continue growing dramatically in the coming years due to the renewable energy demand and favorable conditions in the region.

Challenges

While the Southwest region has great potential for solar energy due to ample sunlight, there are some challenges to developing large-scale solar farms. Two major obstacles are land availability and transmission infrastructure.

Utility-scale solar projects require a lot of land, often hundreds or thousands of acres. The Southwest has large areas of open desert suitable for solar, but permitting and regulations can restrict development. Land must be properly evaluated and set aside for renewable energy projects. There are also concerns around environmental impacts and preserving sensitive habitats. Finding large contiguous areas of public lands suitable for solar farms is difficult, especially near major cities.

Even when suitable sites are identified, limited transmission infrastructure is another barrier. New solar capacity needs connections to the electric grid to deliver the power where it’s needed, which often requires building costly new transmission lines over long distances. Upgrading regional grid infrastructure to handle large influxes of solar generation takes long-term planning and investment. The remote locations of many Southwest solar sites compound these interconnection challenges. Building out transmission is essential but complex, involving coordination between multiple utilities and grid operators.

Cite: https://www.nrel.gov/docs/fy03osti/33233.pdf

Other Promising Regions

While the Southwest has the highest solar potential overall, other areas of the United States also have abundant sunlight and high potential for solar power generation. Three states, in particular, stand out:

California ranks second only to Nevada for solar resources. The state benefits from nearly year-round sunshine, especially in southern California and the Central Valley. California leads the nation in total installed solar capacity, with over 25 gigawatts as of 2020. Major solar projects are located in the Mojave Desert region. (energy5.com)

Texas has great solar potential across much of the state. Central, west, and south Texas receive very sunny conditions. Austin, Dallas, Houston and San Antonio are leading cities for solar adoption. Texas ranks fifth nationally for installed solar capacity, with over 7 gigawatts online. (arrowenergy.us)

Florida’s climate lends itself well to solar power. The state averages over 230 sunny days per year. Utility-scale solar has expanded significantly, especially in rural counties in central and northern Florida. Rooftop solar is also popular, with over 100,000 homes powered by solar statewide.

Future Outlook

The future looks bright for solar energy growth in the United States. According to the Solar Energy Industries Association (SEIA), the U.S. is expected to add a record 33 gigawatts (GW) of solar capacity in 2023.

SEIA projects that over the next 5 years, the U.S. will install more than 113 GW of new solar capacity. This is a 30% increase over installations from the previous 5 years. By 2030, SEIA forecasts that solar will provide 20% of U.S. electricity generation.

Deloitte forecasts that by 2040, solar could generate over 1,000 GW, meeting over 20% of U.S. electricity demand. This dramatic growth will be driven by continued cost declines and technological improvements in solar panels and energy storage systems.

One major area of growth will be utility-scale solar farms, which are becoming increasingly competitive with fossil fuels. Residential systems will also expand as prices drop and financing options improve.

Overall, analysts predict solar power has a bright future in the U.S. thanks to favorable economics, government policy support, and increasing environmental awareness among consumers and businesses.

Conclusion

In summary, the Southwest region of the United States has the highest solar energy potential due to a combination of optimal latitude, high elevations, and sunny weather conditions. Major solar installations have already been built to harness the abundant sunlight and more are planned for the future. While there are some challenges like transmission capacity that need to be addressed, the outlook is bright for large-scale solar energy production in states like California, Nevada, Arizona, New Mexico, and Texas. With the right policies and continued technological improvements, the Southwest could become a major producer of solar power for both local use and export to other parts of the country.