I apologize for the delay in this post, got busy this week.

My last post covered the basics of how the solar panels work at a nuclear and chemical level. This post will cover the equipment needed to interconnect the panels with your electrical system.

There are a couple of different ways to tie in your solar arrays with the utility grid. The first is referred to as Direct Grid-Tie or Intertie, this is the most simple and inexpensive way to utilize solar energy, there is no battery back-up. It starts with your solar array on your roof, these panels are connected in series and/or series-parallel depending on the need. From here it would run through a DC Disconnect and then to a Grid-Tie Inverter. The Inverter takes the DC electricity that is produced in the arrays and converts it to AC electricity. After the electricity is converted to AC, it runs through another disconnect that attaches to your main electrical panel. The electrical panel then ties to the utility company’s meter and into the utility system. If you were to produce enough power to sustain your home the utility meter would not spin at all. One major issue with this type of set-up is that if you were to lose utility power your solar arrays would no longer work, this leads us to our next Grid-tie system.

The Battery-Based system is very similar to the Intertie system except with battery back-up capabilities. With this system you would see a combiner box between the solar array and your battery bank along with a charge controller, this combiner box would be a collecting point for all of the solar array wiring. From the battery bank you would then run the DC through an inverter like in the Intertie system. From the inverter you would more than likely have a small emergency electrical panel just with critical loads (like a furnace and fridge) if you lost power. The inverter and battery bank would then power these crucial loads for your home during power loss. The inverter would also run through an AC disconnect and feed directly into your electrical panel and out through the utility meter. This type of installation is more expensive than the Intertie method, but you have some peace of mind during power outages.

Another thing to remember about battery systems is that wet-cell batteries do not last forever and typically require general maintenance 3 to 4 times a year. Unless you go with sealed batteries which do not need maintenance, but the convenience will cost ya!

There is also an off-grid solar option which relays completely on non-utility power for those that want to be “Off the Grid.”

Home Power Magazine This is a great site for some general information. If you want more in depth information you can buy a subscription. If you are serious about sustainable power I recommend getting one, I have one and have learned a lot from it.

Next Post - Determining the most Efficient Size for your Home

Continuing from yesterday’s blog where I laid out some electrical basics, I’ll begin with the solar panels themselves.

A solar panel is a photovoltaic module interconnected with multiple photovoltaic cells. The term photovoltaic means that light energy is converted into either current or voltage, depending on the desired outcome. When a light photon hits a photodiode it excites an electron causing it to move…simply put. Most solar cells are created with silicon (crystalline, polycrystalline, and non-crystalline), the reason for this is that silicon has a chemical make-up of 14 positive protons and 14 negative electrons with the possibility of 4 additional electrons being gained on the outer shell. The silicon creates a crystal lattice where every silicon atom is connected to four other silicon atoms and they all share the electrons.

This balance, while naturally impressive, does us no good because there is no incentive for the electrons to move. At this point we see other elements added to the crystal structure (this is called doping), like phosphorus which has 5 electrons in its outer shell and boron which only has 3. Now we have an imbalance, we have extra electrons that need somewhere to go and open spaces for them travel. (Phosphorus-silicon is referred to as n(egative)-type and Boron-silicon is referred to as p(ositive)-type).

There is no net charge with this crystalline structure until the two types are joined together. This then causes an equalized junction where the negative electrons line up on the p-type side and the positive electrons line up on the n-type side. Electrical conducting channels are then crisscrossed between the silicon wafers and allow a path for the electrons to travel. This is the basic solar cell module.

Once a light photon of a certain amount of energy and wavelength hits the p-side it causes the electron to break free. Since the p-side is full of the same force it is attracted by the n-side. Making the move from one side to the other will hopefully cause the electron to jump to the crisscrossed conductors and wallah, we have an electrical circuit.

To be continued…

I’m sure by now everyone knows that solar power is energy harvested from the sun. In terms of sustainability, it is a fantastic power supply. You know you are going to have sun light until the sun burns out, which hopefully won’t happen anytime soon. Ever wondered how solar power works, here is a very brief synopsis.

Electricity is the flow of electrons from one place to another. We use conductors like copper and aluminum wire to get the electrons from the main utility distribution centers all the way down to your toaster. There are three (basic) important terms that coincide with electricity: Voltage, Amperage, and Wattage.

Voltage is the measure of electrical potential (electromotive force) of a circuit.
Amperage is the measure of the total amount of electricity that passes a given point at a given time.
Wattage is the measure of the amount of electrical power provided by the circuit.

Not to get too boring here, but if you have 2 of the values above you can always find the third.
Volt X Amp = Watt, Watt/Amp = Volt, Watt/Volt = Amp

Not much of segue here, but there are 2 types of current, DC, which is Direct Current and AC, which is Alternating Current. DC is a steady stream of electrons flowing from one point to another, it is the type of current that is used in vehicles and other electronic devices, it is the only type of current that can be stored in a battery. It always travels one direction. AC on the other hand goes from a positive peak to a negative trough and the back again (think sine wave) it reverses its direction many times a second, it is 60 times a second in the US. The measure of that reversing is called hertz. This is the power that comes from the utility company and is utilized in homes and businesses.

That’s probably enough for today, I will continue on next time. Thanks for reading!

With energy costs that will only continue to increase in the future and it still being unknown how much it will end up costing Americans for carbon offset fees, sustainable power is starting to sound pretty good. The idea of solar power (and wind power) could be extremely viable in the near future for Kansas homeowners, because of this, Greenwave is beginning to learn more about cost effective installations and what applications are most efficient in Kansas.

Depending on where you live, how your house is situated, whether or not you have continual sun exposure, and if you have a good wind flow can determine the best sustainable application for you. Some things to consider for solar power: southern exposure, a decent amount of roof square-footage, trees that would impede the sun, near-by homes that are taller, and hail/wind damage. Solar power is great for Kansas, we have a lot of days of sunshine (between 200 and 275) throughout the year. Wind power takes up a lot less space and can produce a decent amount with the average wind speed in Topeka being about 8 to 12 mph pretty consistently. Most people don’t realize that they make wind turbines that are now 48″ and smaller in height, require a very small amount of wind speed, and make less than 5 decibels at 5′, and produce anywhere from 500w to 10kw.

Next article - Solar Power, How it Works