Blowing in the Wind, Baking in the Sun.
My home energy (electric) bill runs about $400 a month during the summer, $200 a month during a short time in the fall and spring, and $300 a month during the winter. I literally salivate at the idea of producing my own home energy. I mean, look around.
Energy is all around us in one form or another and it’s almost completely free. But there is a fly in the ointment. The high cost of energy is in the collection, storage, conversion, transmission, and utilization.
I’m not going to talk much about the power company grid system, or exotic energy collection/utilization systems–such as leaves and plants–but I will go over a few of the basic methods available to the average home owner.
If this short article wets your interest, you can do more in-depth research and experimentation. While I believe that highly trained and educated scientists are essential in the long run success of any endeavor I also believe that in the short run amateur tinkerers are just as essential.
While we can throw around terms like kinetic, potential, chemical, thermal, and electric energy, the fact remains that almost all energy that we can consider for home use comes from the sun. Even the coal and oil we use –the fossil fuels–are basically stored energy from the sun.
Hydroelectricity is generally out of the range for most of us, since few of us have a river running next to our home. Hydro generated power is also completely dependent upon the sun to transform matter from liquid to gas and back–and wind.
Wind is caused by differences in atmospheric pressure, solar energy acting upon the atmosphere (there’s that sun again!), and the rotation of the earth.
Not many of us can consider using nuclear energy. So, it looks like those of us who consider home power generation are going to be limited to solar power and wind power.
The first part in home power generation is to “collect” the power. Solar power has more potential options for this, so we’ll start with wind power. Early examples of wind power are simple sails on a boat, the Dutch windmills, and the old water pumping windmills that were used in the dry western part of the United States where I was raised.
I can remember exploring rural parts of New Mexico when I was a kid and finding an old farmhouse that used a windmill and battery storage for electrical power.
I’m no spring chicken so the old farmhouse had to be from the early 1900s. I looked it up and can find that wind power for electricity has been in use since before 1890.
I’m not sure when the first windmill was set up for electrical generation but cursory research indicates that such power was being generated in 1887 in Scotland and Cleveland, USA. Wind energy production is not new.
The basic method of power generation from wind is to use a windmill, sail, or other wind catching device to harness the power of the wind. Various types of windmills are the wind turbine, darrieus rotor (which looks like half of an eggbeater), savonious, helical, tower mills, american windmill (the old western stock tank type), and almost any combination of wind harnessing “wing” you can imagine. But none of this matters!
Collecting wind energy is easy. We know how to do it. We’ve been doing it a long time. It is easily adaptable for home use. The amount of energy you can “collect” may not be enough to power your home (unless you have one of those windmills that are so big they knock the buzzards out of the air and scare the entire neighborhood when it rotates) but every little bit helps. Storage of the power so you can use it when you need to is one of the big problems. We’ll get into energy storage in a little while.
Solar energy is also not new. A rabbit sitting on the sunny side of a sand dune on a clear, cold, winter day is using the sun to keep warm. A south facing green house is using solar energy to extend the growing season.
I used to set out a black 5 gallon bucket of water early in the morning so I could use the sun heated water in a shower late that evening.
But now we want to use solar energy to produce massive amounts of power in a form converted to electricity. The current most viable methods of producing electricity are through photovoltaics and concentrated solar power. Photovoltaics uses a “solar cell” to directly produce electricity through the photoelectric effect.
Concentrated solar power is the collection and condensing of the suns rays using lenses, reflective dishes, or mirrors. The concentrated sunlight provides heat which can then power conventional (mostly) electrical generators.
I have cooked a lot of hot dogs using concentrated solar power, but photovoltaics, or the solar cell, is probably the most viable option for home energy production.
How much electricity can you expect to get from solar power? At noon on a clear day the sun delivers about 1000 watts (1 kilowatt) to a square meter. In 2011 solar cell efficiency is about 15%.
Under laboratory conditions with newer, experimental solar cell technology scientists see 20, 30, even 40% efficiency. Of course, we’re not always at noon, nor do we always have clear days.
Let’s assume a 10% efficiency for a working solar cell system with 6 hours of good sunlight. This means you’ll see 600 watts of power from every square meter of solar panel. Let’s now assume an average home electrical consumption of 12,000 watt hours.
I expect this to go down in the future, but right now this is what we’ll use. Divide the 12,000 watt hours by the 600 watts of production and you’ll have a basic idea of what size panel you’ll need to supply your home. The answer is 20 square meters which is right at 215 square feet. This is easily within the capacity of most homes.
We can do it right now. One problem is that the photovoltaic cells and related equipment are still a bit expensive when compared to the cost of conventional power generation. Another problem is energy storage for those times when the sun isn’t shining.
Electrical energy storage is a big problem. The electric companies are all hooked up on a grid. Consumers use the electricity from this grid. The biggest problem for electric companies is frequency and voltage.
In the United States the electrical voltage and frequency is 120 and 240 volts at 60 hz. for homes. If more power is being generated than being used the frequency will go up.
If power usage goes up the frequency will go down. Thus the electric companies have to manage the frequency. They can also take generators offline or put more online as needed.
Electric companies don’t need nor generally use electrical storage other than the grid system. The home energy producer does need storage. Due to the way we must generate our power it sometimes comes at inopportune times and in voltages that are not readily usable.
We store and convert this energy to required voltages when needed. Storage is usually in the form of batteries. Electrical storage technology has lagged behind the power generation technology.
I expect it to catch up one of these days. Until it does it will continue to be a major hangup in home power generation.
Conversion of home generated electricity simply means that we take what we’ve stored and convert it into voltages, frequencies, and forms that we can easily use.
As more home energy is produced we might expect to see equipment rated to use different voltages than the standard 120 and 240 volts. Some RV appliances and tools already use lower voltages. I’m not sure how this will work out, but we’ll go with what we have.
Power transmission for the home is not a problem. We simply use what we’ve already got. In the future I expect to see energy usage go down. This doesn’t mean we will use fewer electrical appliances or equipment. It means that we will become more efficient in what we use.
This will be part of the future. I expect electrical equipment, appliances, lighting, and every aspect of our future energy requirements to become much more efficient.
How that will work out I’m not sure. I’m just a tinkerer. I think our energy future is bright. Right now it’s a little dark. We’ll have to work our way through this. There is light at the end of the tunnel. I’m looking at it!