Electricity from the Sun – Top Ten Things to Know about Solar

Posted on: March 28th, 2012 by admin

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As I travel the Twin Cities and beyond doing solar site assessments for local home and business owners, I tend to hear the same questions about solar energy. There is an ever-growing group of home and business owners that are environmentally conscious, wanting to do “their part” to make things better. As energy prices continue to rise, solar has become cheaper, more efficient and easier to install, and the financial incentives have never been better. The science of being “Green” is now a part of everything we do. Sooner or later, someone will strike up a conversation with you about solar energy.

 

Want to be the expert? Here are the 10 things you need to know.

 

1 How does it work?

The sun emits units of energy in photons. When a photon comes in contact with a solar cell, the photon makes an electron jump from one surface to another on the panel. Electrons moving in the cell create a current (electricity). As the solar cells within the solar panel are wired together, more and more electrons are jumping and creating more current resulting in electricity to power your home or business.

 

 2 How does shading affect solar production?

While a full shading analysis is required to install solar at any site, property owners can get a good idea of how much sun they have by checking for shade a few times at the install site between 9:00AM and 3:00PM. If there is a 14’ x 6’ space or larger that remains shade free during your test, you probably have a good site for solar energy production. Tree trimming is always an option too.

 

3 Do solar panels work when it’s cloudy or covered with snow?

Clouds do restrict the ability for photons to reach solar panels. However, just like you can get sunburned on a cloudy day, you can also produce electricity from the sun on a cloudy day. Production will go down during cloudy periods but your site’s “cloudiness” potential is included in shade/climate analysis of the site. The same is true for snow. Usually that snow comes off on its own after a few hours of sun. While a shallower pitched panel may collect more snow in the winter time, that panel is also more perpendicular to the sun in the summer time producing more power.

 

4 Does temperature affect solar electric production?

It sure does, but not in the sense that you might think. When sun energy is turned into electricity, the electrons move along wires creating current. As more electrons fly down the same wire, heat is created due to the resistance of the electrical flow (think about your toaster). However, as air temperature lowers, so does the resistance of the material and electrons can move more freely. The good news is as temperature decreases, solar electric production increases! A cold sunny day will be one of your highest producing days.

 

5 What tilt angle should solar panels be to catch the most sun?

Typically the best angle is about equal to the latitude of the installation site (45º in Minnesota). A solar panel is utilized most effectively when it is positioned perpendicular to the sun. This is difficult because the sun angle changes daily and seasonally. While trackers can be used to maximize this effect, most solar panel installations are “flush mounted” such that the panel is the same angle as the south facing roof area. The production loss for non-flush mounted panels is typically not enough to require costly and complex structural changes to the installation. Most believe installing the panels flush to the roofline provides the best aesthetics.

 

6 What about re-roofing after a solar panel installation?

Installing solar panels is at least a 25 year investment (most material warranties are for 25 years). Therefore, it’s critical to install panels only on a relatively new roof still in good shape. We highly recommend only installing solar on roofs that are 10 years old or less and in good shape. While it is possible to remove the panels and re-roof around structural attachments, it can be a pain and will cost more in labor.

 

7 Can solar panels face any direction?

There are best practices. It is recommended in the Northern Hemisphere to face solar panels due south to maximize production. If panels are directed Southeast or Southwest, solar production drops by 5-7%. If you install the panels facing straight East or West, solar production drops 21-24%. Is it possible? Yes, the systems just won’t produce as much electricity. Fortunately, new utility rebate programs incentivize panels facing any direction.

 

8 How much space do I need to install solar panels?

We suggest having at least a 14’ x 6’ south facing space. That area would be enough space to fit 4 solar panels on your roof. The more shade-free space you have, the more panels you can install. The more panels you install, the greater the environmental benefit, financial payback and your impact on energy independence.

 

9 Can you store electricity from the sun?

You sure can! You can store electricity produced by the sun by utilizing batteries and the options are limitless. While it is possible, the upfront costs and little advance in battery technology have made non-battery systems more cost effective. Batteries might still be the best solution for your rural home or cabin.

 

10 What does solar installation cost and what incentives are available?

Many factors contribute to the wide range of installation prices you might see including size of system, materials used, complexity of design and installation.The payback largely depends on the installation site characteristics like shade, panel angle, panel direction, available area and incentives. Therefore payback is much more difficult to estimate than cost. Finally, solar power incentives can control up to 50-90% of the installation costs. Most residential installations can cost $3,000 to $10,000 after incentives. Contact us below for the latest pricing and incentives update. Financing is available in most cases to minimize upfront cost and most projects have a great chance of remaining 100% cash flow positive with certain programs. In the end, few investments result in the personal satisfaction, zero maintenance, ongoing savings and environmental impact solar energy provides.