Sustainable Future sells, designs, and installs solar electric systems to generate electricity for your home or business. Our customers enjoy lower utility bills and the knowledge that they are reducing pollution and fossil fuel consumption every time the sun shines. The major system types are listed below.

Grid-Tied Solar Panel Systems

With a grid-tied solar pv system, you can use power provided by your solar system and the local electric utility. Grid-tied systems are popular for several reasons. First, you can install a photovoltaic system that fits your budget, even if it doesn't generate as much power as your home or business is using. Any extra electricity that you need is provided by the grid. In addition, if it's a sunny day and you aren't using much power, you can feed any excess electricity generated by your panels back out to the grid. The utilities are glad to see systems such as these because they help reduce peak demands on hot sunny summer days. Many local utilities (including TVA) will buy the green power you produce at attractive rates.

Another reason for the popularity of grid-tied solar electric systems is that no large banks of batteries for backup power are needed, thus reducing the cost and complexity of the system.The only drawback to purely grid-tied solar panel systems is that if the power goes out on the grid, your power will go down as well, to allow workers to safety repair the line.

However, if power outages are minimal in your area, you won't be without power very often.

Grid-Tied with Battery Backup

If you're considering a grid-tied solar photovoltaic system but want the ability to power critical appliances during a power outage, then a battery backup may be for you. The advantage of these systems is that if there is an outage on the utility grid, you will still be able to draw power from your backup batteries. It's generally not practical to use a battery backup system to keep a power-hungry air-conditioning unit going during a power outage, but items such as fans and energy-efficient refrigerators are often realistic.

Photovoltaics for Off Grid Homes

In some remote areas, connecting a solar photovoltaic system to the utility grid can be cost-prohibitive or impractical. These customers generally consider an off-grid system, where the solar panels are used to charge a large bank of batteries and these batteries are then used to power all appliances in the home. Off Grid systems involve additional components and must be carefully designed around expected energy needs. Many off grid homes also use backup generators for additional power when necessary.

Choosing the Right Solar Power System for Your Home or Business

If you're interested in a solar photovoltaic system, you'll want to consider the following.

• Grid-tied or off grid? If you're in a remote area, you may need an off-grid system. If power is locally available, a grid-tied system without battery back up will be the less expensive option.
• What is an inverter? Watch this excellent video of a roundtable discussion moderated by one of Sustainable Future's advisors, Bill Brooks.

 

   

 

• Where should I put the solar panels? Take a look at your building and property. Good locations are typically an unshaded, south-facing roof, or another open area of the property where some south-facing solar panels can be installed. A solar site analysis is a good investment to help you choose the best place and will be an excellent opportunity to discuss the advantages of different types and sizes of solar power systems.
• How will the panels be mounted? Choices include roof-mounted solar power systems, pole mounted solar power systems, and ground-mounted solar power systems. Roof-mounted solar power systems can be slightly less expensive than a pole mounted system; however they can be less efficient if your roof does not point directly south at the proper angle. Complex roof lines can also cause undesirable shading.
• Do the solar power panels need to be tilted at an angle? Ideally, yes. However, if you prefer the look of flush-mounted solar power panels on your roof, this can be done with a small decrease in efficiency. A solar site analysis can tell you how much efficiency you will lose by not mounting them at the best angle. If efficiency is of primary importance, we suggest tilting the solar power panels at latitude and installing a pole-mounted solar array where you can seasonally adjust the angle of the solar power panels to the sun.
• What happens at night or when it's cloudy? With a grid-tied solar system, you'll just use power from the grid at night. For off-grid solar systems, you'll need a battery backup or generator.
• What size system do I need? This depends upon how much power you are using, and your budget. Customers with grid-tied solar systems can choose to generate anywhere from a tiny percentage of their overall energy use to ALL of their energy use, based upon their budget. We recommend making your home as efficient as possible - that way you need a less expensive solar system. Your energy use habits have a huge effect on your power bill. Consider the following two examples: The "Green" family of four uses 300 kilowatt hours of electricity per month. They have energy efficient appliances, excellent insulation, solar hot water, and use a wood stove for heat in the winter. To maintain their home using only renewable energy, they spend about $25,000 for a photovoltaic system. The "Brown" family lives in the same size home with many air leaks, no insulation, lots of inefficient appliances, and an outdated heat pump. They may spend ten times the amount that the "Green" family spent to create a net zero energy home.