The Light Stuff

February 1, 2010

In my last blog I talked about my presentation on solar energy to the kids at Oran M Roberts Elementary School. My blog focused on what solar energy is, types of collectors, and consumption of energy. This week, I want to focus on the really good questions that the students at Roberts Elementary asked me. Here are some of them.

Which panel is better for collecting solar energy: concentrated solar or flat photovoltaic cells?

Concentrated solar is used for most of the large scale solar plants. Photovoltaic are mostly used for smaller projects, such as residential and off grid power generation.

With all that said, why should we use solar energy?

UBBINK Intersole : Pour l'étanchéïté
Creative Commons License photo credit: Trebosc

On a sunny day, the Sun shines down on us with 120 watts per square meter (or 7.8 square kilometers to power a house). Right now, the average household is about 2500 square feet (or .78 square kilometers). Does that mean that all households will grow seven times as big in the future? Probably not. What it does mean for solar is two fold. It means that there will be more large-scale solar energy production and our electrical uses will become more efficient.

Solar energy may be expensive now, but the more solar collectors they make the cheaper they will get.

Currently there are many incentive programs to help people and companies to go solar (a list of the current programs).

And then there is the future (for instance, future solutions that students from Oran M Roberts are going to come up with).

Two of these future problems are better battery storage and smart grid. They will find a way to take all that “use it or lose it energy” and store it so it can be used when it needs to be used. How are they going to store it? It could be in batteries (lithium sulfur) or something else. It could be using near frictionless fly wheels, or it could be something that has not been invented yet (There is more in heaven and earth then dreamt of in our philosophy).

A smart grid would be useful, especially with better energy storage. A smart grid would get you the energy you need, when you need it and when you don’t need it, send the energy to where it is needed. With the use of new super conducting lines, less electricity would be lost through transportation.

Renewables are predicted to jump from supplying 7% of our energy to 30% over the next 40 years.

Can we use solar energy on other planets or moons?

Buongiorno dalla Stazione Spaziale Internazionale!
Creative Commons License photo credit: Impala74

Yes, NASA uses solar energy to power probes and the ISS. However after a probe goes out further then the asteroid belt, current solar collectors can no longer pick up enough sunlight to power them. Solar power would also be useful to help power a lunar base at the moon’s poles.

What kind of energy does the sun provide?

The sun supplies us with light and heat, both of which can be transformed into other types of energy. A good example of this is a radiometer which converts heat energy into motion. In space, the momentum of photons may be used to move space craft.

Where are the largest solar power stations?

The largest concentrated solar power is the Solar Energy Generating Systems which produces 354 megawatts and is located in the Mojave Desert in the state of Nevada. Another large power plant is the Nevada Solar One which produces 64 megawatts in Las Vegas.

The largest photovoltaic power plant is the DeSoto Next Gen Solar which produces 20 megawatts in Arcadia, Florida.

How much electricity can I get from solar panels?

The panels top out at a certain amount. A 250kw solar panel can gather up to 250kw of power at any given time. Here is a solar calculator that will give you an estimate of how much solar power you could collect.

What are the best solar cities in America?
Drum role please. They are (in alphabetical order)

Ann Arbor, MI
Austin, TX
Berkeley, CA
Boston, MA
Denver, CO
Houston, TX
Knoxville, TN
Madison, WI
Milwaukee, WI
Minneapolis/Saint Paul, MN
New Orleans, LA
New York City, NY
Orlando, FL
Philadelphia, PA
Pittsburgh, PA
Portland, OR
Sacramento, CA
Salt Lake City, UT
San Antonio, TX
San Diego, CA
San Francisco, CA
San José, CA
Santa Rosa, CA
Seattle, WA
Tucson, AZ

What other countries use solar power?

China and India are both growing by leaps and bounds for solar. Currently China produces less than 100 megawatt hours, but in 10 years they plan to produce over a gigawatt of electricity using solar. India is in a unique situation both because it has large parts of its population living off grid and it has a 600 terawatt potential. Right now India plans to be up to 20 gigwatts by 2020.  Another big solar country is Germany, which produce 3 gigawatts of electricity using solar cells.

What is the difference between a photon and ultraviolet light?A photon is a measurement of electromagnetic radiation, or a “unit of light.” Ultraviolet light is electromagnet radiation that has a shorter wavelength than visible light (Although the Mantis Shrimp can see in it).

Will Solar power ever replace fossil fuels?

293 - Sun Texture
Creative Commons License photo credit: Patrick Hoesly

Yes, eventually. It will take time to get the solar collectors up to a greater efficiency. The infrastructure also needs to be built up to use renewable energies in intelligent ways and not just a “use or lose” fashion. Also, we have 10 more billion years of sunlight left (after 10 billion years the sun will have increased enough in size to destroy the atmosphere).

Every year teams of college students put together solar powered cars to race across America in the American Solar Challenge. A couple of teams have already signed up, but I’m sure there is still room for some more.

And of course there is the new They Might be Giants song “Why Does the Sun Shine.”

Authored By Daniel Burch

An inveterate punster, amateur chef, and fencer, Daniel B has a double degree in History and Museum Science from Baylor. He currently serves as the Assistant Program Coordinator for the Wiess Energy Hall and Adult Education at HMNS.

One response to “The Light Stuff”

  1. Raime says:

    Yet ANOTHER awesome post, D! I think flat photovoltaic panels are cheaper than traditional grid energy because they pay for themselves between 18 months and three years depending upon the individual home’s needs.

    Also, I think solar panels are better for people in third world countries and in rugged areas. In fact, nomadic shepards in Mongolia set up their ger (yurt) with photovoltaic panels while maintaining their traditional lifestyles (this info courtesy of the Genghis Khan exhibit!).

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