Are You On or Off? Know Your Solar Power Grid Systems!

Here Comes the Sun

With increasing utility bills, more affordable solar electricity installation, significant tax breaks for those willing to take the plunge and improved dependability built into the technology, more and more mainstream homeowners are electing to use solar power to generate all or part of their electricity. Indeed, you’re more likely to find solar power systems in middle to upper-class homes than remote 1970’s-style communes due to the significant initial purchase and installation costs of photovoltaic — also known as “PV” — systems. What was once a lifestyle or issue-based decision has now come to include systems installed purely for the significant energy savings expected during the 25 or more year lifespan of a PV system.

Solar power systems, Solar Hot Water

Grid-Tied Versus Off-Grid Systems

There are essentially two types of solar electrical systems available for consumers’ consideration: grid-tied or off-grid systems. Neither is intrinsically better or worse than the other. Some homeowners will have both options available to consider while a few others will be required to use an off-grid system due to their distance from existing power lines and the prohibitive costs to connect to their homes to them. “Grid” in both of these system types refers to the existing power distribution system. Grid-Tied Systems are connected to the existing or surrounding power lines and are the most common type of system. As indicated by their name, Off-Grid Systems remain unconnected to any outside utility-based electrical power source. Both types utilize photovoltaic (PV) panels to “generate clean, renewable energy when exposed to sunshine.” A “solar electric inverter” then converts DC power generated from the solar panels into the required 120V AC power that our appliances and gizmos require to work.

How Grid-Tied Systems Work

When the PV panels of Grid-Tied Systems soak up sunshine on a bright, sunny day, the resulting electrical power feeds into the house’s electrical utility meter. “Excess” electricity not required by your home, returns to the grid as you “sell” the overage to the local electrical company. During cloudy days when the energy provided by your home’s PV cells is inadequate for your needs, you borrow back from the larger electrical utility. When electrical service is lost in an area, all grid-tied systems shut down too, in order to prevent “back splash” injuries to linemen working to repair the larger grid system. Because of this safety feature, grid-tied systems require either an expensive large battery back-up system for power outages or the use of a gasoline-powered electrical generator to produce electricity during area outages. Alternatives to either batteries or generators include “roughing it” by heating with a wood stove, collecting water in bathtubs and large buckets for household use, using candles or kerosene lanterns for light and having canned foods on hand for simple meals.

Solar panel systems, Grand Canyon Visitor Center Photovoltaic Panels

Benefits of a Grid-Tied System include:

  • An easier and less complicated installation;
  • Markedly less expensive than an off-grid system when calculating KW/hour costs to produce;
  • Security in having the larger utility grid system when necessary;
  • Ability to earn money selling excess sunshine back to the larger utility.

How Off-Grid Systems Work

Off-Grid Systems work in precisely the same way as Grid-Tie systems once their complex installation is completed. However, these systems are completely independent of larger utility systems and are thus unable to store or borrow power so easily. Instead, off-grid systems usually rely on very large, expensive and short-lived lead acid batteries for these functions. Off-grid systems can, however, also utilize gasoline-powered electrical generators on a limited basis under situations when power produced by the PV system is insufficient.

Benefits of an Off-Grid System may include:

  • Savings of tens of thousands of dollars to connect to a distant power lines;
  • Destruction of trees and erosion-preventing grasses and shrubs necessary to install such connecting lines;
  • Greater reliance on “solar gain” — a fancy term for sunny days — before secondary electricity producing measures are required.

Solar Energy — Global Solutions

Solar energy is clean, reliable and easily installed in most situations. According to, Deutsche Bank recently released information indicating that “the global solar market will become sustainable on its own terms by the end of 2014” and will thus, no longer require subsidies to perform in countries as varied as India to Italy. Clearly, our ability to capture the energy provided by every sunny day will determine our success in decreasing our global reliance on fossil fuels.

About the author: Ryan McNeill is the President of Renewable Energy Corporation, a solar panel installation company based in Maryland. Ryan has collaborated with the American Solar Energy Society, Sustainablog, Energy ViewPoints and other solar industry experts.

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