Hydropower has been used for millennia in most countries of the world. Its longest application has been for use in mechanical tasks, such as grinding grain. With such simple mechanical devices as a "noria", it has also long been used to lift water. Within the last 100 years, hydropower was applied to the conversion of its kinetic energy to electrical energy. Today, hydropower produces 24 percent of the world's electricity and supplies more than 1 billion people with power.

The obvious advantage of generating electricity in this manner is the very high (around 90%) conversion efficiency (compared to a typical conversion efficiency for a fossil fuel power plant of about 35%.) Additionally, there are no emissions to the atmosphere associated with this generation. The most controversial drawback is that the flooding produced behind the dams. canyons.

Well-known examples of hydroelectric facilities in Arizona include Hoover Dam (on the border with Nevada) and Glen Canyon Dam (near the border with Utah). Together these dams can generate about 3,000 MW of electrical power. The reservoirs that each dam creates (Lake Mead and Lake Powell) are heavily used for recreation. Other hydroelectric dams include those on the Salt River and the Colorado River below Hoover Dam. Several sites have been suggested over the years for additional large projects. These have been successfully resisted in all cases because they would infringe on scenic areas, such as Grand Canyon.

At least 22 sites have been identified in Arizona for pumped storage facilities, that is, ones that use off-peak power to pump water back behind dams, making the water again available for the generation of electricity during periods of peak demand. At least 37,000 MW of potential installed capacity has been identified for the state. To date, only a few have been built, all of which are associated with existing dams.

For more information on hydropower, a technology analysis is available from the National Renewable Energy Lab (NREL) web site.

Other Renewable Energy Sources

External links:



Biomass is an organic renewable energy source that includes materials such as agriculture and forest residues, energy crops, and algae. Scientists and engineers at the Energy Department and National Laboratories are finding new, more efficient ways to convert biomass into biofuels that can take the place of conventional fuels like gasoline, diesel, and jet fuel.

In the interim, visit this site for information: 



Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water. Hydrogen can be produced from a variety of domestic resources, such as natural gas, nuclear power, biomass, and renewable power like solar and wind. These qualities make it an attractive fuel option for transportation and electricity generation applications. It can be used in cars, in houses, for portable power, and in many more applications.

In the interim, visit this site for information: Hydrogen Fuel Basics

Solar Space Heating

  • DOE - Active Solar Heating discontinued

    The helpful information once on the EnergySavers.gov website designed to help American residents save energy in their homes, workplaces, and vehicles is no longer available.  This resource was removed in February 2019.  However the information was rather dated.  The above link now goes to an article about the history of EnergySavers.gov by a commercial organization.  Linked for info only, not as a recommendation. 

  • Space Heating for Commercial Buildings
    From the Florida Solar Energy Center at the University of Central Florida.

  • Space Heating with Active Solar Energy Systems
    From North Carolina State University.

Renewable Energy: An Overview - Solar

Updated December 11, 2013

Arizona is the sunniest state in the nation. It receives more than 4,000 hours of sunshine each year. This makes Arizona an ideal state for making solar energy work.

The modern solar industry, founded in 1974 following the Arab oil embargo of the previous year, experienced tremendous growth from the end of the 1970s through the late 1980s. The mainstay of the solar industry during that timeframe was solar water heating. It is estimated that more than 100,000 solar water heaters were installed in Arizona during the 1970s and 80s.

Today, Arizona ranks second only to California in market share for the burgeoning rooftop solar photovoltaic industry. Although solar electricity is only about one percent of the energy mix in Arizona, analysts predict phenomenal growth for solar power over the next two decades.  Traditional market drivers like favorable public policy (rebates and net metering) and tax credits, are getting a boost from falling prices and growing acceptance of alternative financing mechanisms that allow commercial and residential end-users to lease rooftop solar electric systems. 

And as the solar industry grows, so does its beneficial effect on society, such as greater energy independence, improved environmental enhancements, and positive economic impact on jobs. In 2012, the Solar Energy Industries Association estimated that 9,800 people were employed in the solar energy industry in Arizona and approximately 120,000 full-time, permanent jobs nationwide.

The US Energy Information Administration (EIA) predicts that nationally the photovoltaic (solar electricity) industry will grow by 11.6 percent a year through 2040 and that the solar thermal industry will grow at 3.6 percent annually. 

But, solar energy is more than just equipment.  

Passive solar homes (homes that are designed for natural heating and cooling) are popular in both mountain and desert areas of the state. Some of these homes have adobe, rammed earth, or straw bale as a building material. Others solar homes feature strategies and techniques such as solar porches, greenhouses, solar clearstory windows, trombe walls and solar air heaters.

Whether in rural areas or urban settings, Arizonans throughout the state are proving that solar energy can be used by anybody. Solar energy is not a vision of the future; it is an opportunity for today.