Solar Panel Safety

With a flurry of recent solar panel related fires, some would-be solar buyers are wondering if these alternative energy products are safe enough for their homes and businesses. While these fears are largely misplaced, solar energy is not without some inherent risks, as is almost any product, especially if it is not properly installed. However, the few hazards posed solar panels are easy to avoid through regulation and education.

In order to understand the potential dangers of solar panels, it helps to know what one is. Essentially, a solar panel is a grid of wafer-thin disks called photovoltaic cells, which are usually made of crystalline silicon. When photons of sunlight bounce off the surface of these highly-polished "PV" cells, they knock electrons out of their orbits. The electrons then pass through a special converter called a p-n junction diode, which essentially turns them into electrical energy. PV cells are connected with wire conductors and spread on a special layer of thermally conductive cement, which helps keep the panel from overheating. A layer of glass or faux glass usually protects the cells on both sides.

Although solar panels have protective measures to prevent overheating, they must still be installed with caution. There is little danger of panels spontaneously combusting, but solar panels should be elevated off of surfaces so that air can flow and cool them. It is also better to install solar panels high off the ground so they receive unobstructed ventilation.

Faulty wiring is frequently the cause solar panel fires, so if this isn't your forte, have a professional wire the system. If you do choose to wire things yourself, make sure wire is big enough to handle the power in your system, that it is well insulated, and that it is either grounded or tied to the grid to protect against lightning strikes.

Solar panels are relatively easy to maintain, but they can get very hot. Any organic materials that touch a solar panel could potentially burst into flames. Always keep combustible materials away from your solar panels, and trim back any nearby tree branches - this will also help keep your panels out of the shade and make them more efficient. Keep your panels clean by hosing them down or wiping them off with a rag and some glass cleaner. Monitor your wiring for potential insulation flaws, melting or gnawing from rodents. Install a fuse to protect against shortages, and do not try to replace a fuse or a breaker if you do not know what you are doing.

In 2010, a house in San Diego caught fire, and it exposed a significant problem with solar panels for firefighters. Most houses do not have a switch to cut the power from the panels in an emergency, so firefighters cannot put out the fire as quickly or effectively. Moreover, solar energy systems that are used for heat are different from those used for electricity, so they pose a different set of problems. As such, it is imperative that every solar panel system be clearly marked, and that the system have a remote disconnecting switch.

In addition to fire hazards, solar panels also pose potential chemical safety risks to the environment and human health. When solar panels are not properly disposed of, they leak dangerous chemicals, and when raw materials are improperly extracted to make panels, miners are exposed to severe health risks. Furthermore, chemical spills that occur at panel-producing plants endanger the surrounding population and environment.

Like all energy products, solar panels do carry some risks. Without proper installation, maintenance and construction, solar panels can damage the environment and threaten human life. However, the potential dangers of solar panels can and should be easily circumvented by strict regulation and extensive public education.

Measuring Solar Panel Efficiency

In a climate of rising fear over dwindling fossil fuels, homes and businesses have begun installing solar panels to augment or replace their current energy systems. These panels are relatively simple to maintain, but dirt and improper placement can significantly decrease their power output. In order to ensure that you are obtaining the optimal value from this product, you should regularly check the efficiency of your solar panels. This is a simple procedure, requiring little more than multimeter, and it will maximize your savings.

First, you need to determine the area of your panels. If you don't have that data from the installation, just use a measuring tape.

Second, you need to figure out the maximum solar radiation for the exact spot on Earth where your solar panels are sitting. Essentially, this is a measurement of how much power the sun is bringing to your location — i.e., the maximum power your solar panels could theoretically provide, keeping in mind that current panels achieve only a maximum of about 20% efficiency. You can measure solar radiation with a solar meter, or you can look at the database on the National Renewable Energy Laboratory's website, which provides average solar input for various regions throughout the year. 

Now you need to figure out how much power your panel is actually providing. Use a multimeter to measure the voltage and current that your panel is producing, then multiply these figures to calculate the power produced (P = VA). Keep an eye on your units — your panel area should be in meters squared, and your power should be in kilowatts.

To determine your panel's efficiency, just divide the power output of your solar panel by the solar input of your location (both in kilowatts per meter squared) and multiply by 100. If the number is lower than it should be (around 20), you may need to clean your panel, adjust its angle or ask a professional to inspect it. 

Installing a Solar Panel at Home

These days, the cost of fuel rises almost as fast as concerns about global warming and funding for terrorists. Solar energy is becoming an attractive alternative to petroleum and coal, and you have probably even seen arrays of photovoltaic cells on large office buildings. Unfortunately, the trend is growing less rapidly in residential areas, largely because of the upfront cost, the aesthetics and the presumed hassle of installation. However, these disinclinations are generally misguided. While solar panels are certainly not cheap, there are a plethora of tax rebates available on state and federal levels, and the deduction -- or elimination -- of your electricity bill will pay you back and then some over time.

If you're particularly stingy and love breaking out the power tools, like my dad, you can lower the upfront cost of a panel even more by installing it yourself. Be advised that if you aren't an electrician or an avid do-it-yourselfer, this project probably isn't for you, and you will likely wind up saving yourself a lot of money, time and pain by simply calling in a professional. If you can use a ladder, a stud-finder and common sense, though, you can probably at least perform the basic setup.

The first step in setting up a solar panel is making sure you can legally install it. Check with your homeowner's association (HOA), unless you live in one of the following states, which have laws protecting solar access rights: Alaska, Arizona, California, Colorado, Delaware, Florida, Idaho, Maine, Maryland, Massachusetts, Nevada, New Jersey, North Carolina, Oregon, Vermont, Virginia and Wisconsin.

The following states have have guidelines that offer homeowners some leeway in installing solar panels, but you should still check: Georgia, Indiana, Iowa, Kansas, Kentucky, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Mexico, New York, North Dakota, Ohio, Rhode Island, Tennessee, and Utah.

If you live in one of the other states, start pressuring your government to grant you solar access rights, and in the mean time, be sure to check with your HOA before you install anything.

No matter where you live, you'll also need to obtain a building permit, so contact your local building authority (county and city). In some states, you actually have to be licensed to install solar panels. You will also have to have your solar panel inspected, and you will have to obtain permission from the power company to connect. (If you hire professionals, they take care of all this.)

The second step is to select the optimal spot for a panel. You want to put it in the place that will receive the maximum amount of sunlight at noon. Typically, this is the south facing part of your roof, but if you have several trees or a large shadow-casting building on the south side, you may need to hunt for a better spot. Also, you need to make sure your roof is sturdy enough to hold a panel, or you're going to wind up with a costly hole. You certainly don't have to install a panel on the roof; you can also put it on a pole in the yard, but these take up more space and are easier to see from the road (if aesthetic appeal concerns you).

In addition to where you put your solar panel, you will have to determine the optimal angle for your panel. The basic formula for this is adding 15 degrees to your latitude in the winter and subtracting 15 in the summer (yes, this means you have to adjust your panel throughout the year). If you really want to maximize your solar energy output, multiply your latitude by .9 and add 30 degrees to your latitude in the winter; subtract 2.5 degrees in the spring and autumn; and subtract 52.5 degrees from the winter angle in the summer.

When you have optimized the setup location and angle, you are ready to begin installation. Most solar panel kits come with a mounting apparatus. Typically, this involves two metal rails and a metal piece that screws into the panel and slides in between the rails, kind of like the sliders for a drawer. EasyJack and Tile Trac are the most common brands.

For the installation, you will need a stud-finder or the blueprints of your house, a drill with a pilot bit, steel bolts, a ladder, roof flashing or caulk, and of course a solar panel kit.

1. Use the stud-finder to find the studs on your roof. You can also look at your blueprints, but this is less reliable. You need to drill into studs because they offer the sturdiest support and are less likely to splinter or break.

2. Measure how far apart the holes on the mounting rails are, and drill holes in the studs this far apart. Use a pilot bit so you don't split the wood.

3. Line up the holes in the mounting rails with the holes you drilled and insert steel bolts through them. Seal the area around the bolts with roof flashing or caulk so your roof doesn't leak.

4. Put the mounting interface on the solar panel (each kit has its own straightforward instructions) and slide the interface into the rails.

5. Make sure the solar panel is at least 6 inches from the roof: this will give it proper ventilation and keep it operating efficiently (and keep it from starting a fire). Adjust it to the angle you calculated.

6. If you have background in electric work, connect the conduit of the panel to the inverter. If you don't know what that means, call a professional electrician.