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FAQs: Photovoltaics 101

 

What is a photovoltaic panel and how does it work?

Photovoltaic (PV) panels are typically made from high purity silicon wafers similar to those used in computer chips. When light strikes the surface of the wafer it dislodges electrons, which then are collected and output as electric power. A typical solar panel is made of dozens to hundreds of these wafers all soldered together and framed with aluminum and then covered with a very tough low reflective glass. Because PV panels have no moving parts they have a very long life span with very little maintenance.

Why is it good to have solar electric panels in Colorado?

Colorado, along with the rest of the southwest, is one of the best places in the country for photovoltaics. We typically get 300 sunny days per year here and have a relatively high altitude and low latitude. All these factors combine to make Colorado one of the sunniest places in the country.

What are the parts of a PV System?

There are four main parts to any PV installation.

Is there a battery involved?

No, we install only grid tied systems. In other words, you are generating electricity that is fed into the electrical grid. If you want a system that is off the grid, say, for a mountain cabin, we can refer you to an associated company that can install a battery operated DC system. Note that your regular appliances will not work on a DC system unless they each have a converter/adapter. Or, you can purchase appliances specifically manufactured to work on DC rather than AC.

How much maintenance is required?

Very little. Typically PV panels require no maintenance. About the only thing that an owner can do is to wash them down if they get too dirty, but even that doesn't happen very often. Typically, the panels are kept clean enough by the rain and snow falling on them.

What is a Watt?

A watt is a basic unit of power. Think about the light bulbs in your house. They are rated in watts. The more watts they use, the brighter they are. Typically a 100 watt light bulb produces four times as much light as a 25 watt light bulb and it uses four times as much power. Solar panels are rated in Watts. This rating is the amount of power the panel can produce under full, direct sunlight.

What is a Watt-hour?

A watt-hour is a unit of energy. It is a measure of power over a span of time. If you have a 100 watt light bulb and you leave it on for one hour, it will consume 100 watt-hours of energy. In Colorado, a PV panel will produce its rated power for an average of 5.0 - 6.5 hours per day. This means that a 200 Watt panel will produce an average of 1000-1300 watt-hours per day. The actual number will be higher in the summer and lower in the winter.

What does shade do to PV Panels?

PV Panels are very sensitive to shade. Typical panels are broken up into sections, which in turn are made of several photocell wafers. If any part of a section is shaded, then that section stops providing power to the panel. This means that any shade can cut the power output dramatically.

Is there any water in these panels?

No, photovoltaic panels have no water in them. They generate electricity directly from sunlight.

What is the difference between different brands of panels?

While all the panels we use are excellent and carry the same warranty, each brand of solar panel has some unique attributes. Some panels are more efficient than others, some use different types of solar cells, some are manufactured to tighter tolerances and each looks a little different. In our experience the one factor that is the most important to our clients is dollars/watt. At various times, various companies have specials or just lower prices in general. We always strive to give our customers the best possible price on their system. Of course, if a customer has a desire for a specific manufacturer, we are happy to oblige them.

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