Compare the two types of systems and consider the pros and cons of each in the detailed list below.
Off-grid systems
Off-grid solar systems are powered solely with the energy generated by the system’s panels. “An off-grid system gives you the ability to operate separately from the utilities, because you’re producing your own power and don’t have to pay an electric bill every month,” explains Randy Zechman, owner/CEO of Clean Solar, Inc. in San Jose. “The downside is you have to pay close attention to the amount of energy you use.”
Advantages
• Off-grid systems allow homeowners to build in remote areas where there are no power lines or limited access to power utilities. They can be thousands of dollars cheaper than having power cables installed.
• No electricity bills
• No electric rate hikes
• You’ll have access to power when grid-reliant customers face power outages, grid outages and rolling blackouts.
• You’ll reduce your carbon footprint and decrease your dependence on energy through more efficient use of power.
Disadvantages
• You’ll need room to store large solar batteries and a battery bank.
• You must closely monitor energy usage so you don’t run out of power. Inclement weather for several days can drain the batteries.
• Off-grid systems can be expensive and may be ineligible for tax credits and rebates. A typical off-grid system costs twice as much as other systems per kilowatt-hour. This is due to the high costs of setup and maintenance.
• You won’t have access to power if weather, natural disasters or accidents damage or destroy your solar panels or solar system.
• Routine maintenance (charging and replacing batteries, adding water, panel upkeep) can be expensive and time consuming.
• It’s uncommon for banks to finance off-grid systems.
Grid-tied systems
Grid-tied systems are linked with power utilities, which enable the home to use the power generated by the solar system as well as power from the local utility. These systems can also feed power back into the grid during times of low usage and high production.
Advantages
• Backup power is available through the public utility (PG&E) if the solar system goes down or is damaged. • Any excess power the solar system generates can be sold back to the power grid.
• Power from the grid can be lowered or even free in the case of inclement weather or emergencies.
• Some systems can be designed to allow transitioning to a completely off-grid system.
Disadvantages
• Homes must be located close to power lines, as grid-tied power systems require connection with the local utility. The system will draw from this power source during times of low sun and to supplement the power usage.
• Grid-tied system installations require large roof surface areas in sunny locations (for panel placement).
• Most grid-tied systems aren’t large enough to fully power a home, so you’ll still incur some energy costs. The majority of grid-tied system owners report savings up to 50 percent.
