The Basin and Range produces nuclear energy and has significant potential for both geothermal energy and solar energy, which has been expanding rapidly. The region also develops energy from the Colorado River, which runs along the western boundary of Arizona and Nevada. Due largely to complex active tectonics, much of the Basin and Range region has poor prospects for fossil fuel production. In southern Arizona and New Mexico, the Pedregosa Basin—and the early Cretaceous rift basins that have been superimposed upon it—contains a thick sequence of upper Paleozoic rocks, including carbonates and black shales. The rocks in this basin have not been found to have commercially significant petroleum or coal deposits.

Solar Power

Solar power in the Southwest has grown extremely quickly in recent years, thanks to the solar resources located in the Basin and Range. The Sonoran Desert extends through southern Arizona and the Chihuahuan Desert from southern New Mexico into the southeastern tip of Arizona; both of these deserts make for prime solar energy territory (Figure 6.12). Between 2010 and 2015, Arizona increased its installed solar capacity from 110 MW to 2303 MW; today, it produces 13.3% of the country's solar power and is ranked second in the nation for solar electric generation (behind California). By contrast, New Mexico and Utah currently have only 365 and 255 MW of installed solar capacity, respectively. New Mexico expects to install another 1428 MW of solar capacity over the next five years, more than five times the amount installed over the past five years. While production of solar electric power has grown exponentially in Arizona and in the US as a whole, more than half of the country's solar electric production is found in California. The total US output of solar power is also still dwarfed by other sources. For example, in August 2015, five times more electric power was produced in Florida from burning natural gas than the entire country produced from solar power that month, and in Arizona, the explosive growth of solar production brought electric production from non-hydro renewables to just 3.8% of the state's total.

Figure 6.12: Locations of existing photovoltaic power plants overlaid on a map of the annual average solar resource for the Southwestern US.

The Basin and Range holds some of the world's largest photovoltaic power plants, though most of these large-scale plants are found in California or Nevada. The Agua Caliente solar project in Yuma County, Arizona currently has a 348 MW capacity, and a much larger project of 1.2 GW has been proposed just across the Arizona-California border in Needles. The Solana Generating Station near Gila Bend, Arizona is a 295 MW plant that uses parabolic mirrors to concentrate a large area of sunlight into a relatively small area (Figure 6.13). As this concentrated light is converted to heat, it drives a turbine that is connected to a power generator. The Solana Generating Station was the first solar plant in the US to use molten salt as a means of storing thermal energy.

Figure 6.13: More than 3200 mirrored parabolic troughs are used to concentrate light and heat at the Solana Plant in Gila Bend, Arizona

Geothermal Energy

Geothermal energy comes from heat within the Earth, which is created on an ongoing basis by radioactivity. This energy powers mantle convection and plate tectonics. The highest-temperature conditions exist in tectonically active areas, including the Basin and Range, Iceland (a mid-Atlantic ridge), Japan (an area of subduction), and Hawaii and Yellowstone (areas with hot spots). Warm springs associated with tectonic activity in the Basin and Range have been enjoyed by the region's inhabitants for hundreds of years, beginning with Native Americans. This tectonic thermal energy is associated with a thinning of the crust, high heat flow relatively close to the surface, and groundwater that has been heated by cooling intrusive volcanic rocks. The heat of the Basin and Range has become the basis for both geothermal power plants and "direct use" operations (that is, use of geothermal energy at the site where it is generated). Typical examples of direct use include geothermally heated greenhouses, swimming pools, and buildings. Western Utah has several geothermal plants and many direct use facilities (Figures 6.14 and 6.15), and is the third leading producer of geothermal energy in the US (behind California and Nevada, where geothermal energy is also associated with the Basin and Range). New Mexico is also beginning to develop its geothermal resources.

Figure 6.14: Researchers from the University of Utah test a geothermal plant’s wastewater injection flow in order to optimize steam production and improve the plant’s capacity.

Figure 6.15: Geothermal energy resources in the Southwest.

How does geothermal energy work?

Geothermal power stations use steam to power turbines that generate electricity. The steam is created either by tapping a source of heated groundwater or by injecting water deep into the Earth where it is heated to boiling. Pressurized steam is then piped back up to the power plant, where its force turns a turbine and generates power. Water that cycles through the power plant is injected back into the underground reservoir to preserve the resource.

There are three geothermal sources that can be used to create electricity. Geopressurized or dry steam power plants utilize an existing heated groundwater source, generally around 177°C (350°F) in temperature. Petrothermal or flash steam power plants are the most common type of geothermal plant in operation today, and they actively inject water to create steam. Binary cycle power plants are able to use a lower temperature geothermal reservoir by using the warm water to heat a liquid with a lower boiling point, such as butane. The liquid butane becomes steam, which is used to power the turbine.

Other Alternative Energy

Arizona ranks 10th in the US for hydropower generation, with 13 hydro and pumped storage facilities producing approximately 663 gigawatt-hours (GWh) of power for the state's energy supply, though this only accounts for approximately 6% of the state's demand. Arizona's largest hydropower plant is the Hoover Dam, located on the Colorado River bordering Arizona and Nevada. When built in the 1930s it was the world's highest dam, largest electric-power generating station, and largest concrete structure. The plant's total power generating capacity is approximately 2 GW, and it is the sixth largest among US hydroelectric power stations. Approximately 20% of the Hoover's generated power goes to Arizona; another 25% goes to Nevada, and the rest is used by California.

The Palo Verde Nuclear Generating Station (Figure 6.16) near Tonopah, Arizona is the largest nuclear power facility in the US, producing approximately 3.3 GW of power annually and serving more than four million people. This plant is also unique in that it is the only large nuclear power plant in the world that does not use a nearby body of water for cooling; rather, it evaporates water from the treated sewage of nearby cities. The Palo Verde plant uses 76 billion liters (20 billion gallons) of evaporated treated sewage water per year.

Though space is available for wind farms, wind potential is relatively low in the Basin and Range, especially when compared to the Great Plains (see Figure 6.22). The only large-scale wind farm in the Basin and Range region is the Milford Wind Corridor Project in southwestern Utah, with a generating capacity of approximately 300 MW. Other smaller-scale projects are scattered throughout Arizona and New Mexico (Figure 6.17).

Figure 6.16: An aerial view of the three reactors at Arizona’s Palo Verde Nuclear Generating Station. Each reactor has a generating capacity of 1.27 GW.

Figure 6.17: The Macho Springs Wind Farm in Luna County, New Mexico has 28 turbines and produces approximately 50 MW of power.