Living Green

Let’s go read the electric meter. Is it going forward or backward?

Here in western Colorado, we get an average of 300 sunny days a year. So why don’t we use more of that energy from the sun? More and more people are thinking that’s a great idea. As you drive around the valley, you can see that a lot of homes and businesses have new black shiny shingles. Wait, are they something else? Some of them are standing up on little legs; why is that? They must be solar panels. 

It turns out you get the most energy from the sun if you have solar cells that are facing to the south. Not everyone has a roof that faces directly south, so you can adjust your panels so they face south.

The sun shines on the photo voltaic cells and is absorbed by the material in the cells and is put through something called an inverter to convert the direct current output of the solar cells into the alternating current that we use in our homes, businesses and factories to light our lights, run our refrigerators and all of the other electrical things we use.

It is also possible to have a solar heating system that could provide hot water for your bath and heat for your home.  

The solar cells are only going to work at the highest output when the sun is nice and bright, but it turns out that when the clouds are not very thick, some of the light from the sun is reflected off the clouds, and the cells do make a useful amount of power.

This is why we have to run out to see which way the meter is running. The electric meter on the outside of your house tells the electric company just how much power you are buying from them at that moment.

If the television is on, the washer and dryer are running and it’s really cloudy, you are buying lots of kilowatt hours of electricity from the electric company and the meter is going forward.

But if the sun is shining and not many appliances are turned on in the house, you may be selling power to the electric company and they will pay you for that electricity. The meter is going backward. You are using the electricity generated by the solar cells, which are looking at the sun and producing energy from the radiation shining on the solar cells.

If you have windows on the east side of your house and there are no curtains in the way, you can feel that warm energy from the sun coming right through the windows and warming up the room.

Or you might feel it later in the day if you have windows on the west side of your house. That’s solar energy coming right straight through the window to warm the room.

As time goes on, the companies that make solar cells make them more efficient and less expensive. In addition, they are working on new products that will absorb the radiation from the sun and turn it into electricity.

For example, some people believe that the most economical way of providing our electric power is to use the sun to heat water, convert it to steam and use that steam to drive steam turbines. These turbines then turn generators, similar to what’s done in a coal- or natural gas-fired power generating station, but without the carbon dioxide pollution. 

Even now, many businesses and military bases have big fields of solar cells all connected together that provide electric power to supply at least a part of their needs.

Time will tell how economical solar power becomes, but someday you may be able to paint your house with a special paint that will absorb the sun’s energy whichever way it is facing and supply your household needs.

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Jack Kingsley earned a doctorate in physics from the University of Illinois. He spent his career in research and development with General Electric Co. in Schenectady, N.Y.

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Bev Kingsley worked for the Knolls Atomic Power Laboratory in Schenectady and later sold real estate in the capital district of New York State. She was a founding member of the Environmental Clearinghouse of Schenectady.

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Need a little sunshine shed on a scientific topic? Email masc@bresnan.net.