QUIZ: Test your Solar IQ

Think you know PV from CSP? Put your brainpower to the test with our solar energy quiz!

1. How much solar energy reaches the Earth's surface at any given moment?

173 terawatts

1.73 terawatts

17,300 terawatts

173,000 terawatts

Solar energy is the most abundant energy source on the planet. Enough sunlight hits the Earth's surface in 1 1/2 hours to power the entire world's electricity consumption for a year!

2. Of all new generating capacity added to the U.S. electrical grid in 2015, what percentage was solar?





While solar accounts for less than 2% of U.S. electrical generating capacity overall, it is one of the fastest-growing energy markets in the country. With solar power continuing to get more affordable and new installations happening every day, the solar industry is booming. For the first time, more solar generating capacity was added in 2015 than natural gas in the U.S. (Source: FERC)

3. Which U.S. state generates the most utility-scale solar power?





In 2014, California became the first state to generate more than 5 percent of its annual utility-scale electricity from solar power, according to the Energy Information Administration. With several large solar plants phased into operation in 2014, California's utility-scale (1 megawatt or larger) facilities generated a record 9.9 million megawatthours (MWh) of electricity in 2014, an increase of 6.1 million MWh from 2013 and more than three times the output of the next-highest state, Arizona. In total, nearly 1,900 MW of new utility-scale solar capacity was added, bringing the state's utility-scale capacity for all solar technologies to 5,400 MW by the end of 2014.

4. What does the word photovoltaic mean?





"Photovoltaic" has two parts: photo, derived from the Greek word for light, and volt, from electricity pioneer Alessandro Volta. And that's exactly what photovoltaic systems do -- turn light into electricity!

5. Who discovered the photovoltaic effect?

American physicist Enrico Fermi

Italian physicist Alessandro Volta

German physicist Heinrich Rudolf Hertz

French physicist Edmond Becquerel

Edmond Becquerel was the first person to realize that sunlight could produce an electric current in a solid material in 1839, but it took more than a century for scientists to fully understand this process and develop a practical solar cell.

6. What are the most common photovoltaic cells used today?

Organic cells

Plastic cells

Polymer cells

Crystalline silicon cells

Unveiled by Bell Labs in 1954, silicon cells were the very first successful photovoltaic (PV) technology, and they remain the most common PV cells in use today.

7. Roughly how much did the cost of PV solar panels decrease between 2008 and 2015?





Thanks in part to research funded by the Energy Department's SunShot Initiative, photovoltaic solar panels have gotten dramatically cheaper over the past decade. SunShot was created with the aim of making solar power cost-competitive with fossil fuels by 2020, and it has made significant strides toward that goal by supporting the development of more efficient solar cells and cost-effective manufacturing processes.

8. Which of these is NOT considered a "soft cost" of solar power?

Connection fees



Solar panels

Today, soft costs -- that is, all the costs and fees aside from the solar hardware itself -- account for more than half of the price of installing a solar energy system. By taking steps to help reduce soft costs, the Department of Energy is working to make affordable solar power a reality for those who want it.

9. What form of energy do concentrating solar power technologies use to generate electricity?





Concentrating solar power technologies use mirrors to reflect and concentrate sunlight onto receivers that collect solar energy and convert it to heat. This thermal energy can then be used to produce electricity via a steam turbine or heat engine that drives a generator.

10. Which of the following is NOT a technology used in concentrating solar power?

Power tower

Linear fresnel

Cathode ray tube

Parabolic trough

Parabolic trough, linear fresnel and power tower are all types of concentrating solar power systems. They may look very different, but they operate on the same principle, focusing the sun's rays on a central receiver.

11. About how many mirrors are used at Ivanpah Solar Electric Generating System, the largest concentrating solar power facility in the U.S.?





Spanning 3,500 acres of Southern California desert, Ivanpah's 173,500 "heliostats" (each made up of two mirrors) focus the sun's rays on three 459-foot-tall, heat-collecting "power towers." Water circulated through these towers turns to steam, driving turbines that can generate up to 377 megawatts of electricity -- enough to power 140,000 homes in California!

Your Score:

How much do you know about the energy we get from the Sun, and the ways we harness it to generate electricity?

What's the difference between photovoltaic and concentrating solar power? Can you name the soft costs of installing solar energy systems? 

Check out the Top 6 Things You Didn't Know About Solar Energy and take our quiz to show off your solar smarts!