Green Tips for Homeowners

Have you ever wondered if it is practical to consider powering your house with solar electricity? Well, in a recent article at How Stuff Works they asked the question “How many solar cells would I need in order to provide all of the electricity that my house needs?”

If you’re an alternative energy skeptic the answer will not be surprising. Making a series of assumptions about electricity use and basing the hardware costs on today’s rates, the writers concluded that it would cost at least $30,000 to generate enough to provide the electrical requirements of a typical home. And that doesn’t even include the cost of space heating, water heating, cooking, and clothes drying – all of which it was assumed would be done by natural gas.

The numbers go like this. A “typical” home in the US requires an average of 600 watts per hour every 24 hours to run the lights, appliances, computers, refrigerators, TVs, and fans and motors on other appliances such as the furnace, clothes washer and dryer, and so on. That is approximately 14,400 watt-hours per day.

To generate that much electricity using solar cells you would need about 41,000 square inches of solar panels. At today’s prices that would come to about $16,000. And then, because the sun is not available for parts of some days or at all on other days you would need a battery storage system that would cost at least the same – roughly another $16,000. So that puts the price at about $32,000 for the system.

At today’s cost of electricity off the grid that much electricity would cost roughly $525 per year. To recover the up-front costs would take more than 50 years. Long before that time had passed the entire system would have to be replaced – making it even more expensive. And in fact the battery system would probably only last a maximum of 5 years. So it is no wonder that not very many “solar houses” are being built.

Even if we accept these numbers at face value it does not mean that solar energy has no place in the energy mix of the future. It just means that it is important to “get real” about where it is practical to use it.

it is easy to build solar panels at home. Individual solar cells are not very big and you can handle them quite easily.

You place the cells in their panel and connect them in series. After each panel is completed check it for connectivity and then connect the panels to one another. Once the panels are connected and in place, connect the entire array to your battery pack and then to your inverter before connecting to your house.

Solar cells or photovoltaic cells, as we’ll call them here, convert solar energy into electric energy. I’m sure you knew that but in order to understand how to properly build solar panels, you need to know how the electricity is created.

Photons of light strike the semiconductor material, usually silicon, on the cell’s surface. When the photon strikes it knocks an electron loose. There are two types of silicon used to make a cell. One type is negatively charged and the other is positively charged. Layering silicon with opposite polarities increases the cells’ efficiency.

Solar cells are designed to keep the newly freed electrons traveling in one direction only: out of the cell. The electrons gather steam (as it were) as one electron lines up behind another and a flow of electrical current is the result.

Building solar panels is a breeze if you are meticulous about getting each cell in series with the next, checking your solder and any other connections. There’s a channel down each cell where the electrons travel into a tab. The tabs are how one cell is connected to another. Once they are all connected, they are covered with a layer of glass or laminate to protect the cells from the elements. Any residual moisture is eliminated and the panels are placed into position and hooked up together.

The last step is connecting your house’s electrical system to the new solar panels. My opinion is that this is a job for a trained professional. I want certification that everything was done to code (or better). You wouldn’t want a minor issue that you overlooked in the electrical installation to invalidate your insurance policy. The cost of a certified electrician is money well spent.