For further information, please visit the U.S. Department of Energy’s Planning a Home Solar Electric System website page.
In simple terms, solar panels convert sunlight into electricity. This electricity can be consumed in a home or fed onto the electrical grid for distribution. Power from the sun is the most abundant natural resource available; however, our access to this resource is limited by the length of days, our location, and the weather. Solar power has gained popularity in recent years as the advances in technology and tax subsidies have helped reduce costs. There are three essential components of any solar photovoltaic system:
- Solar Panels
- DC to AC Inverter
Sunlight is a pure form of energy that can be converted into other forms of energy through natural, synthetic processes. In the 1800’s A French physicist by the name of Alexander Becquerel discovered the Photovoltaic Effect, a way to convert sunlight into electricity.
Solar Panels are designed to use the Photovoltaic Effect to convert sunlight into electricity. These panels are comprised of a series of interconnected cells made of silicon. When sunlight strikes the silicon cell, electricity in the form of electrons is emitted from the cell creating an electrical current. Each cell only produces a small amount of current; however, when connected together, they can generate a considerable amount of electricity. The size of the solar panel determines how much power it can produce. Typical solar panels used in residential and commercial applications range from 250 to 400 watts. That means that a single 250-watt solar panel, under ideal conditions, could power approximately 4) 60 watt light bulbs.
DC to AC Inverter
Photovoltaic or PV solar panels convert sunlight into electricity, but this electricity is in the form of direct current or DC. Homes and businesses use electricity in the form of Alternating Current or AC. The solar power inverter is an electronic device that converts the direct current (DC) supplied by the solar panels, into the usable and standard form of Alternating Current (AC).
Putting It All Together
Solar panels can be installed on rooftops and in open fields, but the most efficient places are those that are not shaded and have clear exposure to the southern sky. A typical home would require approximately 10kW of solar panels (around 40 solar panels taking up about 17 square feet per panel). These panels are wired together and connected to the DC to AC inverter. The invert first synchronizes itself with the AC power from the electric company then the AC output of the inverter is connected directly to the grid to deliver the energy produced by the panels.
What happens when the Sun does not shine?
At night, the solar panels produce no energy, and the inverter uses a small amount of energy to maintain its synchronization and run its onboard electronics. In the morning hours when the sun rises, a small amount of light is absorbed by the panels and the system begins producing small amounts of electricity. As the sun reaches its highest point in the sky, the panels produce their maximum amount of electricity for the day. As the sun sets, less and less electricity is generated until there is no longer enough light for production. Clouds, rain, and shade from trees and debris have a significant negative impact on solar production. A cloudy, rainy day can cut solar production by 70 to 90%.
What happens when the power is out?
Grid tied solar arrays are designed to discontinue operation in the event of a power outage. Once power is restored, the inverter synchronizes itself to the grid and resumes producing electricity.
Is solar right for me?
There are several factors anyone considering solar should investigate.
- Do you have a rooftop or field suitable for solar installation? Is it free of shade?
- Do you rent a home or apartment? If so, owning your own solar array may be problematic.
- Solar is a long term investment, consider the length of time to recoup your investment.
- Check with your Insurance agent to be sure your homeowners policy covers your Solar investment
- How old is your roof? Solar arrays are designed to work for 20+ years, be sure your roof will not need replacing before then.
- Do you have a neighborhood covenant? Be sure to check your neighborhood association about restrictions concerning solar arrays.
- Check with your accountant to determine if you qualify for federal tax credits.