Solar Quiz: How Much Do You Know About Solar Power?

Are you an energy whiz? Find out with this quiz!

By Megan Phelps

How much do you know about solar energy? Here’s your chance to test your knowledge. Below are 10 questions — all true/false, and all about solar-electric systems. Jot down your choices, then scroll to the bottom of the page to see the answers and add up your score.

The Questions: True or False?

Scientists discovered “the photovoltaic effect”— the concept that light could produce electric current — in 1939.
Most solar cells are made from amorphous silicon.
Solar cells can be made from plastic.
Most solar cells are about 60 percent efficient at converting sunlight into electricity.
A solar panel produces DC power — an inverter converts it to AC.
A typical size for a residential solar-electric system is between 2,000 and 5,000 watts.
Net-metering laws and feed-in tariffs are both policies that help homeowners get paid more for the electricity their solar panels produce.
Over the course of a year, a photovoltaic (PV) system in Albuquerque, N.M., would produce almost exactly the same amount of electricity as an identical PV system located in Seattle.
The United States currently produces more electricity from solar power than it does from wind power.
New Jersey has more PV power installed than any other state.

Answers:

False. It was actually 100 years earlier than that — 1839.
Learn more: This Month in Physics History, from the American Physical Society.
False. Most solar cells are made of crystalline silicon. The alternative is thin-film solar, which is growing, but not yet as common as crystalline modules. Amorphous silicon is just one material used to make thin-film solar panels.
Learn more: How Thin-film Solar Cells Work, from How Stuff Works. Also, here’s a table from the Energy Information Administration (EIA) showing how production of thin-film solar compares to the production of crystalline silicon modules.
True! Plastic solar cells are one type of thin-film solar cell being developed.
Learn more: Information about plastic solar cells from Science Daily.
False. The most efficient solar products are closer to 20 percent efficient. In the lab, the record is nearer to 40 percent.
Learn more: New Solar Cell Efficiency Record Set, from Scientific American.
True. The inverter is needed because our homes run on AC power.
Learn more: Information about how solar systems work from the EIA.
True. The trick here is that you'd be more likely to see that number expressed as 2 to 5 kilowatts. (1 kilowatt = 1,000 watts.) Learn more: Size and cost of a solar-electric system from MOTHER EARTH NEWS. Also, here’s a table from the EIA explaining the units of electricity.
True, and award yourself one bonus point if you’ve ever heard of a feed-in-tariff (FIT) — two if you can define it. If you install a grid-tied photovoltaic (PV) system, you’re in the business of selling electricity to your utility company. Both FITs and net-metering policies set rules about how much you get paid for the electricity your solar panels produce.
Learn more: Our friend Dan Lepinski, co-host of MOTHER EARTH NEWS Radio, has written a glossary of renewable energy terms. Find it on the website of the North Texas Renewable Energy Group. It includes technical definitions of both net metering and FITs.
False. More sun equals more solar electricity, so a PV system in sunny Albuquerque would definitely produce more power over the course of a year than an equivalent PV system in rainy Seattle.
Learn more: Calculating Solar Power Potential with PV Watts, from MOTHER EARTH NEWS.
False. Wind power production is currently much bigger than solar power production.
Learn more: Here’s a big table of electricity statistics from the EIA.
False. California is by far the U.S. leader in solar power. However, New Jersey is No. 2.
Learn more: The Best States for Solar Power, from MOTHER EARTH NEWS.

Add Up Your Score!

How many did you get right?

10+: You have the (solar-electric) power!

7 to 9: Well done. The sun is shining on you.

4 to 6: Not bad, but keep working on your efficiency.

0 to 3: You're still in the dark. Try again!

Photo by iStockphoto

Archived Comments

Elaine Dubin 1/12/2010 9:00:01 AM

Onlysolar and Pete, the problem with your arguement is that very, very few Americans have $15,000+ dollars to spend on solar power up front, i.e. cash. Banks don't really make personal loans that large to individuals anymore, and even if you have excellent credit and could get one, the interest rate would be high. So you'd be saving money on utility bills, but it would take an average person years and years to pay off that loan (if they could get it), which would more than eat the cost savings on their utility bills. Most people finance their cars, and the interest rates on those loans are usually pretty good.
Don't misunderstand me, I am a big advocate of alternative energy, including solar power. But the general public won't spend what little money they have on solar technology until the price comes down. And the manufacturers and installers won't bring their prices down until there's a larger demand for their products. Once the demand is there the price of the components will come down b/c they'll be made on a much bigger scale. Therein lies the double-edged sword of renewable energy. The government really needs to step in here and offset pretty much all of the cost of installing a residential solar power system. But nope, they won't do that. They're too busy sending money overseas (oil), AND borrowing stimulus money from China to bail out banks and whatnot, rather than investing in clean energy made in America. It's madness.
Mark Handy 1/11/2010 6:04:09 AM

You guys should all move to Australia, There is no way you would sell any pv cells if the cost were that high. Early last year you could get a full 5kw system fitted and the Government rebate covered the total cost. Ok now they have reduced the rebate to $2000. So now I would be $6000 out of pocket plus the power companies buy back extra power. Enough to pay it of in around 5 years
heyrakes_2 1/9/2010 11:18:40 PM

this test really shows the "manusha" in the solar power movement. do i really need to know when photovoltaic was discovered, it's nice to know when the light bulb was invented, but the better info would be getting it to work.
i like what Jay Leno said about making your own electricity. "it's like the satisfaction growing of your own tomatoes"
onlysolar_1 1/9/2010 10:36:37 AM

Most of you guys are just blinded (or just idoits) solar power is the cheaps thing on the market. 30% federal more from state and lots more from your utility Co. cover most (ifnot all) of the cost. Most of you asses drive $40,000 plus cars and trucks and act like solar cost to much. I think that 99.999% of the US populations people are just SO, SO,SO ,SO stupid about money your just upside down on your SUV so you can look cool. Stop spending you money on the wrong things!!!!!!!!!!! I could go on but whos listening.
hazel Watson_2 1/8/2010 4:53:40 PM

The only solar power I can afford currently includes my 20 (on sale) solar garden lights, which work better when there's snow on the ground, and the warming western sun that comes through my front windows and storm door. My cats love to lie in the warmth.
I would like to have both solar and wind working for me!
AJ_4 1/8/2010 2:23:38 PM

i agree with both dave and klohma, pete. Currently the only folk who can go full solar in one bite are the big guys with the money....you wonder why solar isnt on every home? you already know the answer to that....its cuz the equipment is not priced for the homeownner, its priced for the contractor so that money is made....the whole system is geared toward the money end and not the sustainable tech end....so we in the middle who want to get off the grid are left in the lurch...this is the crappy way that our society can show that yes solar is a viable option for power but try and afford it at the costs that the society sets up....another case of dangling the carrot/apple in front of the horse....
i am building my system up slowly as i can afford each part on a pension....and i know there are a lot of others out in the nethers who are doing the same...we are buying and scrounging used equipment so that we can save toward the next purchase of the system...you wont believe how many of us field techs are out in society quietly doing what we do best....innovation, modififaction, production and use....
AJ
David Haggard_4 1/8/2010 10:46:48 AM

No, the tale of only the big guys can afford is true. I'm glad for you, Pete, that you were able to swing $15,000. No, wait. That's AFTER the PV rebate and the federal credits. Not all states offer such rebates. Plus, you're not a "little guy" in a little house. You're a "big guy" in a little house. Coming up with $45,000 or so up front is not in my budget or my credit line. Drop the price of the panels or the film about 75%, and make them available for me to install myself. THEN I might be able to do it.
Pete_15 1/8/2010 9:24:39 AM

The tail of only the big guys can afford solar is false. I'm a little guy who lives in a small home and have added a 5.04 kw system to my roof. With the PV rebate from the state (20,000) and the federal credits (30%) my small system cost about ($15,000) So if everyone learned how to become more energy efficient and then went solar they too might become a net zero home like me. I pay no electric bill and the power company at the end of the year pays me back
klohma 1/8/2010 7:58:09 AM

Solar power may be good for the big guys on the block but is still far too expensive for the little home owner. Good for small things on the rual homestead, electric fences where no power is close by etc.. Installed costs here in Arkansas are approx. 45,000 with, for me, a 12.5 year recovery period for the system. There are no programs in this state other then net metering, selling power back to the local utility company, offered by the state and the Fed's 2000 rebate is nothing compared to the install cost.
In addition here in Arkansas we have net metering, but with current state law it works out in the favor of the utility company. Any excess amount , power produced is applied to next months bill, at the end of the year reverts to the utility company and you don't get paid.

In addition the size you get fothe 45000 is not enough to power a home for everything, something that most individuals would require before investing. With the current cost giving you only around 3-5kw of power I have to leave just about everything off and still see lights flicker to dim when the well pump starts. I currently have a 5kw gas generator and it is not enough power to run anything other then lights and keep the refrig and freezer running.
So for solar to be adopted as a standalone power source for the home the cost is going to have to drop by 50 to 75 percent coupled with an increase in power delivery. Till then the gas generator will prevail out here in the woods.