Sun
It warms our skin. It lights the world. It makes life on earth possible.
The sun is an enormous ball of gas that provides light, heat and other solar energy to our solar system. The sun is made entirely of gas, the primary one being hydrogen. Nine planets and their moons, tens of thousands of asteroids and trillions of comets revolve around the sun.
The sun’s radius—the distance from its center to its surface—is about 432,000 miles, over 100 times the radius of the earth. The temperature of the sun’s surface is about 10,000° Fahrenheit (F) or 5,800° Kelvin (K), a metric unit astronomers use to measure star temperatures. The sun’s core reaches temperatures over 15,000,000° K.
The sun is brighter and more massive than 95 percent of the stars in the Milky Way. The enormous energy of the sun collects from millions of nuclear-fusion reactions that occur deep in its core. In a fusion reaction, nuclear matter is converted into energy when two atomic nuclei combine to create a new nucleus. Considered a young star, the sun is 4.6 billion years old and has enough nuclear fuel to remain the same for another 5 billion years.
The human factor
Energy from the sun, in the form of sunlight, supports almost all life on earth. Plants use the energy of sunlight to initiate photosynthesis, a process that converts solar energy into chemical energy, thus producing food and maintaining the normal level of oxygen in the atmosphere. Without the sun, we wouldn’t be unable to eat, breathe or naturally produce Vitamin D, which plays an important role in the maintenance of our organ systems.
The earth’s climate is also determined by the sun—specifically by how much solar energy gets trapped in the system. Research shows that while climates have always fluctuated over time, the earth is warming more quickly today than it has in the past. According to the Intergovernmental Panel on Climate Change, this is because of human activities, including the burning of fossil fuels that release greenhouse gases into the atmosphere and the cutting down of trees that would absorb the resulting carbon dioxide.
Since ancient times, humans have used a range of technologies to harness the enormous renewable energy potential of the sun. Indeed, every day in America’s sun-drenched Southwest, there is the potential to collect thousands of megawatts of energy by utilizing the profound power of the sun to create electricity. This region has the solar-energy potential to meet the electricity needs of the entire U.S.
To capitalize on this potential in today’s modern world, solar energy is harnessed in several ways. Concentrating solar power (CSP) is a solar technology that uses thousands of mirrors to concentrate sunlight onto solar receivers and convert it to heat. This thermal energy can then be used to produce electricity. Photovoltaic systems, on the other hand, use solar cells or panels to convert sunlight directly into electricity. Finally, solar hot water heaters include storage tanks and solar collectors that generate hot water for your home.
Leading by example
Recognizing the potential of concentrating solar power (CSP), ACCIONA developed Nevada Solar One to demonstrate that this technology could perform on a commercial scale. ACCIONA’s Nevada Solar One is the largest CSP plant to be built in the last 17 years, and it is currently providing clean energy to more than 14,000 homes in Nevada annually. The building of CSP plants in the U.S. could augment and eventually replace many fossil-fired power plants, leading to a diversified low-carbon energy portfolio within just a few decades.
Concentrating solar power – ACCIONA is the first company in nearly two decades to prove the commercial viability of this innovative technology.
Photovoltaic systems – They have very little impact on the environment, making them one of the cleanest renewable energy technologies available.
Solar hot water – A solar heating system can provide up to 85 percent of domestic hot water energy.