Practical Solar Power

Solar Power-How it works physically

• The sun's light strikes a solar panel.
• The solar panel uses the light-energy to make a direct current, DC, electricity flow. That DC electricity is useless because you cannot plug any house hold device into it and get it to work (except possibly your toaster or curling iron and they would not work reliably). Everything in your house has been designed to work with alternating current, AC, electricity.
• The DC electricity flows into an inverter, which converts the DC electricity into AC electricity.
• The AC power is attached to your home electrical system at the circuit breaker.

Solar Power-How it works regulatorally

Grid tied vs. Non-Grid tied

With the solar power system hooked into your house through your circuit breaker panel you have a grid tied system, it is tied the power grid that you already rely on (in western Pennsylvania [excluding greater Pittsburg] that is Penn Power's electrical grid who is a subsidiary of First Energy) . Having a grid tied system means that

• You can still rely on the grid when you don't make enough electricity for your house (you are an energy importer).
• When you make more electricity than you can use it feeds back onto the grid and makes your meter spin backwards (you are an energy exporter).
• You help keep the dirtiest electricity power plants off line. You make energy when it is sunny, a peak time for running air conditioners.
• You have to apply to connect your energy generation equipment to the power grid.

Having a non-grid tied system means that

• You must have batteries to store energy for the times the sun is not bright enough for your needs.
• You can't rely on the grid when you don't make enough electricity for your house, the lights go out and your fridge stops.
• You need a system big enough to cover all of your energy needs from day one.
• There is no application and you have bragging rights for being off the grid.

In my opinion the only benefit of having a non-grid-tied system is the bragging rights and skipping the interconnection application.

Applying to tie your system to the grid.

Connecting to the power grid with small scale power generation equipment (<50kW for residences) is called interconnection. Pennsylvania amended the laws governing small energy generators in 2008 and mandated net metering with the power company responsible for installing the meter capable of turning backwards at no charge to their customer. You must apply to make the connection before you install your system. To fill out the application you need

• to know your energy use history (just get out your old electricity bills) since the net metering law is based on the idea that you will not be a net exporter of energy year after year (but you can be for months at a time).
• to estimate the amount of energy you will produce.
• provide some specifications about the inverter you will be using.
• provide a one-line diagram. This shows in a cartoonish way how the electrical energy moves from the solar panels through the inverter into your breaker box and out to the utilities meter. It is important to include all of the information that is shown in First Energy's example (e.g. manufacturer of the breaker box and amperage of service).
• provide a site plan. This tells the linemen how and where to shut off your solar power equipment if they need to work on the lines so they don't run into any surprises. First Energy's example. I drew ours one-line drawing and site plan using the free software called xfig. It is native to the free software system ubuntu linux and can also be installed directly on windows using these instructions.
• to supply the $100 application fee.

We have currently have a complete application in and are awaiting their comment. When the company gives the ok it is provisional, it allows you to install and test your solar power system. When it is correct, you must have it inspected by the local electrical inspector.

Solar Power-How it works economically

Pennsylvania and the Federal government have incentives available for those who install alternative energy systems. Pennsylvania: The program for solar power money is called Pennsylvania Sunshine Program and a good discussion of this program is available at solar power rocks. Since this is a tax rebate program we couldn't use it as Westminster College is a tax-exempt entity. The other catch that I see is that the application must go through a certified installer, so this may not work for a DIY installation. Feds: The federal government has a 30/% Solar Investment Tax Credit which is discussed here. According to the Department of Energy your solar power system needs to be installed before December 31, 2016.

Where we bought our equipment

Wholesale Solar, they had the most straight forward pricing information and were quite responsive to any needs we had.