You wouldn't think there was anything different about William and Deborah Lords' house in Portland, Maine. It looks pretty much like any other nice, Northeast-style, single-family home. But while the neighbors are paying hundreds of dollars a month for energy, the Lords are paying about $10.
Their home is powered almost entirely by the sun. Roof-mounted solar panels collect and convert so much of the sun's energy that the family can heat the house, run appliances, heat water for showers and keep the house lit up -- everything the rest of us accomplish with power from the grid -- with almost no help from dirty, dwindling fossil fuels.
And the Lords are doing this in Maine -- not an extraordinary location for solar potential. Portland is ranked 59th on CleanBeta's list of U.S. cities' solar capacity [source: CleanBeta]. Imagine what you could do with solar power in a city with really serious sunlight.
In this article, we'll look at the best places in the United States to build a solar-powered home, whether you're looking for 100-percent solar power or just enough to put a dent in your carbon footprint (and your electric bill). All of the five cities at the top of the list have at least one thing in common: a very high insolation rating.
Insolation is a common measurement in the solar-power industry. An insolation rating represents how much solar radiation strikes the ground in a given time period, typically measured in kilowatt-hours per square meter per day, or kWh/m2/day. Portland's insolation rating is 4.51 (above 5 is a pretty good rating) [source: CleanBeta]. That's nothing compared to the cities on our list.
As you can probably guess, they're all closer to the equator than Portland is. Equatorial cities tend to have the highest solar potential because sunlight hits the ground at a more direct angle at the equator. The more direct the sun's rays, the more efficiently solar panels can collect them.
Coming in at No. 5 on our list is Sin City -- Las Vegas, Nev.
If you've only seen the neon-soaked Strip, you probably don't think of Las Vegas as a particularly eco-friendly city. But in fact, it's a pretty "green" place to be, with cash incentives to replace grass with drought-tolerant landscaping and a couple of hydrogen gas stations in town owned and run by the government.
And then there's the solar-power potential: Las Vegas is one of the sunniest cities in the country. Nevada requires that state utilities gather 15 percent of their energy from alternative sources; and by 2015, 5 percent of that will have to come from solar [source: Kanellos].
It makes sense: Among major cities, Las Vegas ranks fifth in insolation value, coming in at 6.41. That means every day, the sunlight that hits a single square meter of Las Vegas could generate 6.41 kilowatt-hours of electricity.
That's due in part to about 20 percent more sunny days than the United States average, along with little rainfall. Las Vegas also has less humidity in the air to interrupt the path of sunlight to solar panels -- about 60 percent less than the national average on a summer day [source: City-Data].
Plus, you could use some of your monthly energy savings at the craps table (once you pay off the solar panels, of course).
Next up: Tucson.
If you live in Tucson when 2018 rolls around, you could find yourself using one of the cleanest mass-transit systems in the world: the Solar Bullet. Engineers have proposed a 220-mph (354-kph) solar-power train to carry passengers the 116 miles (187 kilometers) from Tucson to Phoenix in half an hour [source: Alvarado].
It's still very much on the drawing board, but with more than 300 days of sunshine per year to work with, a solar-powered train is a brilliant if expensive proposal -- the first phase of the project would run about $27 billion [source: University of Arizona].
Those same 300 days could power a house for a lot fewer zeroes. Equatorial placement combined with few clouds, low humidity and a maximum monthly rainfall of 2 inches (5 centimeters) leads to a lot of solar-energy potential. Tucson's insolation value is 6.57, placing it at No. 4 on our list [source: CleanBeta].
No. 3 is the city at the other end of that solar train: Phoenix.
Not to be outdone by the other Arizona city on the list, Phoenix has its own major solar project going. It is perhaps less innovative but is far more likely to happen: The Phoenix Suns stadium is, appropriately, running on solar.
Or at least running on 25 percent solar, thanks to 18,000 square feet (1,672 square meters) of solar panels installed on the garage roof in 2008 [source: GizMag]. The NBA team's U.S. Airways Center is cutting its annual carbon dioxide output by 440,000 pounds (199,580 kilograms) by capturing Phoenix's solar resources [source: NEMA].
Those resources are abundant. Phoenix boasts 306 days of sun and just 8.4 inches (21 centimeters) of rain in a year [source: Sun National]. In June, the chance of a sunny day in Phoenix is 95 percent, and it hits the low end of the sunny scale in December, when that chance falls to about 75 percent. Phoenix's insolation value is 6.58, ranking it just a hair above Tucson on the list [source: CleanBeta].
No. 2 on our list, El Paso, Texas, offers more of an insolation jump.
In March 2009, the Texas state legislature reviewed almost 70 renewable-energy bills in its "solar session." With a solid 50 of those bills addressing solar-power technology and incentives, the session was a prime example of Texas' intention to boost its involvement in solar power [source: Galbraith].
Texas is a U.S. leader in wind power, and it has the potential to be a significant force in the solar industry, too. A bill passed in May 2009 makes the development of solar-power plants in the state a far more profitable proposition [source: Ward].
The solar potential in El Paso alone is worth the effort. Coming in at No. 2 on our list, El Paso has 6.72 kilowatt-hours of solar radiation hitting every square meter of the city every year. Almost 300 days of sunshine in a year, 8.39 inches (21 centimeters) of annual rainfall and humidity 20 to 30 percent less than the national average provides a clear path for the sun's rays to reach the ground -- or a roof-based solar-panel array [sources: Infinite Power, City-Data].
The No. 1 city on our list has even more sunlight available to harvest. Albuquerque, N.M., may just be the best place to build a solar home.
Albuquerque has every other decent-size city beat for solar potential. The city sees 310 days of sun every year, and people who install solar panels on their residence there can get 30 percent of the cost back in tax rebates on top of the 30 percent federal rebate for the system [sources: Albuquerque, Reese].
Albuquerque's insolation value is 6.77, which should help New Mexico reach its goal of reducing greenhouse-gas emissions to 75 percent below 2000 levels by 2050 [source: Reese].
But before you move to Albuquerque and set up solar camp, make sure you address a few other issues besides insolation. Is the area you're looking at surrounded by buildings, or does it have a wide, clear view of the sky? To get the most of the available sunlight, you don't want a lot of obstructions. And even more important, does the area allow solar setups? For instance, some homeowners' associations (HOAs) have rules about what kinds of things you can put on the roof. So before you pick a location, make sure your solar panels will be a welcome addition to the neighborhood.
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- Albuquerque Convention & Visitors Bureauhttp://www.itsatrip.org/trip-planning/weather/default.aspx
- Alvarado, Mariana. "High-speed solar train proposed as Tucson-Phoenix connection." Arizona Daily Star. May 8, 2009.http://www.azstarnet.com/business/292000
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