Editor's Note (From Laurie): As some of you know, I used to work in the solar energy industry, but my experience is with solar thermal (space heating and hot water). I'm pleased to tell you that a friend of mine, Jerry Noel, has agreed to share his knowledge as a Master Electrician and a NABCEP Certified solar installer. This is the first of our new series, “Solar Electric Basics with Jerry Noel“.
Solar electric, also technically known as “photovoltaics” (PV for short), is the conversion of sunlight into electricity. The predominant resource for this conversion is the silicon chip; the same kind used in computer cpus. Over the course of a series of articles, I will try to explain how a solar panel system (array) is installed, what it can produce, and approximately cost. I will also delve into many of the many FAQ’s involved with this science.
How much will a solar electric system cost?
That is the most common question, so I will hit it first. The answer is “How much power do you need?” or “How large an area do you have?” There is no easy answer to this one.
If you want a system that will offset your entire utility bill then you need to determine your demand. Do you have 5 plasma televisions, electric appliances, high wattage incandescent light bulbs (that are always left on), multiple video game systems, and a hot tub then you will need a system the size of Rhode Island! Do you have CFL or LED lights? Are your appliances “Energy Star” rated? Do you turn off lights when not in use? Then you could offset most of your electricity usage with a “small” system. I consider “small” as one under 3-kilowatts.
A standard solar module is around 250 watts and is 5.5’ x 3’. This question is almost impossible to answer in a basic format like this. More information is needed along with a shading analysis to give to a good ballpark number. Current trends show that a roof mounted system costs in the area of $5 per watt installed. A pole mounted tracker system, one that follows the sun, costs around $10 per watt. Add $3 or more per watt for anything that has batteries.
Do I need batteries for my solar electric system?
Do you want power during an outage? Solar panels create power in the form of direct current (DC) electricity when the sun is shining. Inverters take the DC and change it to 60 cycle alternating current (AC) for our usage. Underwriters Laboratories requires that all grid connected inverters automatically disconnect from the utility grid if they sense an outage. This is a safety precaution for the utility linemen. Electric utilities have sensors scattered among their distribution network. When they sense an outage, crews are automatically dispatched to rectify the problem. If you are feeding small amounts of power to the grid, it can confuse the sensors and delay the repair crews, potentially endangering people working on the power lines. To have power during an outage, you MUST have a system with batteries (or a generator)!
Can I install a solar electric system myself?
Sure why not? First, grab the black wire, and then grab the other black wire. Oh, by the way, the voltage difference between them is 500 volts. I hope you have good gloves.
Am I trying to discourage you from doing it yourself? Yes.
Am I trying to keep you alive? YES!
I was working on a system a year ago, had good gloves on (but they were a little wet), and touched the wrong thing. It felt like I was hit in the chest with a baseball bat. I’m an electrician and am used to getting a shock. That was PAINFUL! Solar power systems generate seriously large amounts of voltage; why risk it?
Editor's Note: You can attend training seminars to help you get the proper training you need to safely install your system. Also, some contractors may work with you to allow you to do some of the structural work, such as erecting a framework for the panels. Please get proper training before attempting any electrical work. Information on this site is provided for reference purposes only.
Other Posts in this Series:
Solar Site Check – analyzing your location
Designing Your Solar Electric System – getting the most out of your available space
This is a guest post by Jerry Noel. Jerry is a Wisconsin Master Electrician and a NABCEP Certified solar installer. NABCEP is a voluntary credential, considered to be the cream of the crop for renewable energy professionals. NABCEP stands for North American Board of Certified Energy Practitioners.
Jerry is a foreman for Krantz Electric in Verona, WI. They are located a few miles to the south-west of Madison. Krantz Electric does residential, commercial and solar electric projects. In the past, I have taught solar electric theory and installation for the IBEW, Midwest Renewable Energy Association, and Solar Energy International. Please visit the Krantz Electric website for more information.