Solar Energy

The Sun protects all life on earth. This amazing resource radiates energy and fuses hydrogen into helium at its core, giving us both heat and light. This is what we call solar radiation . Just about half of the solar radiation makes it to the surface of the earth. The remainder is either consumed by clouds and the atmosphere, or mirrored. Still, we get enough power from the Sun to meet all mankind's power demands — millions of times over. Solar energy — sun power — is a massive, inexhaustible, and clean resource. Sunlight, or solar energy, may be directly used for heating and lighting homes and businesses, for power generation, hot water heating, solar cooling, and a number of other commercial and industrial applications. Most important, considering the increasing concern about climate change, is the fact that solar power generation provides a clean alternative to fossil-fuel energy, with no air and water emissions, no emissions from global warming, no risks of energy price increases, and no threats to our public health. Solar wealth is gigantic. The amount of sunlight that hits the Earth's surface in an hour and a half is enough to accommodate the entire world's energy consumption for a full year, according to the US Department of Energy. Just 18 days of sunlight on Earth provide the same amount of energy that is contained in all the coal, oil , and natural gas reserves on the planet.

Solar wealth is gigantic. The amount of sunlight that hits the Earth's surface in an hour and a half is enough to accommodate the entire world's energy consumption for a full year, according to the US Department of Energy. Just 18 days of sunlight on Earth provide the same amount of energy that is contained in all the coal, oil , and natural gas reserves on the planet.

The Growth of Solar Energy

U.S. facilities have grown from 1.2 gigawatts ( GW) to an estimated 30 GW today seventeen times since 2008, enough to power the equivalent of 5.7 million average American homes. The average cost of solar photovoltaic panels has fallen by more than 60% since 2010, and the cost of a solar electrical system has dropped by about 50%. Solar electricity is now seen in many states, including California, Hawaii, Texas, and Minnesota, as being economically competitive with traditional energy sources.

The Basics of Solar Energy

So, what are the fundamentals of the solar energy systems? First of all, solar energy systems differ according to size and application. Residential systems are seen throughout the United States on the rooftops, and companies are starting to install solar panels to cover their energy costs. In addition, utilities are constructing massive solar power plants to deliver renewable electricity to all grid-connected customers. There are two primary types of solar energy technologies — photovoltaic (PV) and concentrated solar power (CSP)—regardless of the particulars of a particular system. Owing to the solar panels they see more and more on the tops of buildings or those mounted on the International Space Station, most people are familiar with the PV technology . If the sun shines through one of those solar panels, the cells in the panel absorb photons from the sunlight, producing an electrical field through the layers and allowing electricity to flow. PV systems can be installed on the ground, installed on the rooftop, or mounted on a wall. They can be placed in a permanent position to optimize output and value, or placed on trackers that cross the sky following the sun. Rooftop PV panels provide viable solar power in virtually every part of the United States. A five-kilowatt residential system produces an average of 7,000 to 8,000 kilowatt-hours per year in a sunny location like Los Angeles or Phoenix, roughly equivalent to a typical U.S. household 's electricity use. The second system relies on solar power (also known as concentrated solar power or CSP). This is primarily used in very large power plants, and is not suitable for residential use. This technology uses mirrors to reflect and concentrate sunlight on receivers which collect and convert solar energy into heat. The heat is used to drive a heat engine, normally a steam turbine, which is connected to an electrical generator which is then used for electricity production. Our future largely depends on our ability to tap solar and other renewable energy sources. Expanding technology, tax incentives and solar-adapted utility companies are all promoting advances in the area of renewable energy. Perhaps significant, however, is to note that measured around the planet's entire surface, a square meter absorbs 4.2 kilowatt-hours of energy every day from the sun, or the total energy equivalent of about a barrel of oil every year.