Solar power equals energy independence. For some owners of solar energy systems, home solar power is a means to “untie” their home, lifestyle, and eco-conscience from the dirty side of the regional electric grid. Yet many solar homeowners around the world will vouch for me on this one - being “tied down” is not always a bad thing. In fact, it can be a very lucrative investment that benefits both individual and community.
The literal difference between off-grid and grid-tie home solar power is quite simple. Grid-tie systems are connected to community electric grid, so that back-up power can be provided for the home when the sun is not shining. Off-grid systems are not connected to the local grid. They utilize a “bank” of batteries to store excess daytime energy for use at night.
Lifestyle and finances tend to influence which direction a solar-leaning household will choose to go.
Grid-tie home solar systems are much more prevalent for several reasons:
- Cheaper up front to install - It is easier to tie-in to the grid than pay for and install a safe battery bank.
- Net metering laws or, in some cases, feed-in tariffs are powerful incentives for homeowners to connect to the local grid. Net metering allows homeowners to trade with their utility. Excess solar energy produced during the day is used elsewhere and credited to the solar homeowner to offset the costs of using grid electricity at night. Feed-in tariff laws require the utility to buy that excess daily power at an inflated price, which can turn home solar power into a profit deal.
- Grid-tie systems require less maintenance - Batteries need some occasional TLC and must be replaced every few years (at present technology levels). They can also be hazardous if not handled correctly.
- Benefit the community electric grid - Feeding that clean, green solar energy into the grid during the day, when power demand is at its peak, eases the burden on an already overstressed electric infrastructure. It also helps cities and states reach their renewable energy goals. Furthermore, distributed generation (the collective term for home solar power systems) may play a key role in the Smart Grid of the future.
- More flexibility - Being tied to the grid provides security in knowing that if you have a spike in energy usage (i.e. visit from family, in-home wedding, etc.), back-up is ready and waiting.
Getting off the grid has its definite advantages as well. Particularly for homeowners in remote areas, not to mention those in the developing world without any electric infrastructure, off-grid systems offer:
- Total freedom - Off-grid home solar power means that when the grid goes down, you don’t. There is safety and security in knowing that your home is energy-independent as well. A downed power line 20 miles away and rolling blackouts don’t affect the off-grid homeowner.
- Totally clean, totally green - Bye, bye transmission cables. When you’re off-grid, you are totally free of coal-fired and other fossil-fueled electricity. Your energy is clean and your home’s carbon footprint greatly reduced.
- Off-grid systems also benefit the local community - They make life easier for the local energy grid by providing one less house in need of outside power sources.
- Powering the outer limits - Off-grid systems are essential for folks who want to live “outside the box,” but don’t necessarily want to rough it for the rest of their lives. In comes off-grid home solar power to provide that comfortable, country home of your dreams.
For many homeowners, the most influential difference between grid-tie and off-grid home solar power systems is economics. Money is still a big concern for homeowners, and although prices have been steadily decreasing, solar power is still an expensive investment up front. Hence, the existence of net metering and the prospect of feed-in tariffs tend to override any desire to shun the regional power grid.
Yet there are obvious benefits to both, and given the present state of the national electric grid, plus the likelihood of advancements in energy storage technologies, an off-grid solar power revolution should not be counted out.
Besides, the differences between grid-tie and off-grid home solar power systems are dwarfed by at least one glaring similarity: the use of clean solar energy.