Many times, when people want a solar power system installed, there is a misunderstanding of what it means to be on-grid versus off-grid. A lot of times we hear people say they want to be “off the grid” thinking that is what it means to go solar. What they really mean is that they want to reduce their energy usage, but don’t realize you can do it and still be tied to the grid. On-grid systems stay connected to your power lines which are run by your utility company whereas off-grid ones only rely on the solar system and batteries.
For an off-grid system, in order to store the energy produced by your system, you would need a battery back-up. The batteries that off-grid systems require bring up the overall cost of the system, are bulky, unreliable, and are not as environmentally friendly. This usually defeats the purpose for many of you who are going solar with the incentive to save money and live a greener lifestyle. Since off-grid systems require a battery back-up system, it is not as reliant as it can only hold a certain amount of energy. Additionally, the battery typically has a shorter life span than most solar panels, which means you will eventually need to replace it. Any maintenance required for an off-grid system will not be covered by your utility company, but is dependent on you. Although there are advantages to having an off-grid system, like having power stored in the battery back-up during emergency situations like outages, the overall advantages in comparison to being on-grid are not as beneficial.
Being on-grid and net-metering are the most cost effective ways to store energy for solar systems. Since you are tied to the grid, you won’t need a battery back-up since you can pull energy into or from the grid. On-grid solar projects are typically more simple than off-grid ones because for an on-grid set up, the power goes directly into your utility grid. Simply think of the utility grid as a large battery that is already available for your system to store an unlimited amount of the energy that it produces! When a solar system is grid-tied, the excess power that is produced can turn your net meter backwards and earn you credit from your utility company. For an off-grid battery backed up system, not only do you have to pay for the battery back-up but the excess energy that you produce can’t be exchanged for credit. The biggest drawback of being on-grid is that when the grid goes out, so does your power. However, the reason for this is the grid-tied solar electric inverter has to shut down in order to avoid injuring nearby line workers.
The reasons why on-grid systems tend to be the more popular choice among homeowners getting solar systems due to security and convenience. Majority of solar systems typically offset around 50%-75% of your usage depending on the size of your system, your location, and other various things dependent on your individual situation. With a 50%-75% offset, an on-grid system should still significantly bring down your electric costs while providing a cleaner source of energy. With that said, with an on-grid system, you can rest assured that the rest of your electric usage that isn’t offset can be pulled from the grid.
Remember, having an off-grid system really just means having a home that is not connected to the utility grid. Other than that, a home with an off-grid system can actually use just as much power as a regular home that hasn’t gone solar. Unless you completely want to be independent from your utility company and want nothing to do with them, don’t get your idea of what it means to be on or off grid mixed up. If you live in rural or remote areas where there are no utility companies available then off-grid systems are usually your only option. Don’t forget to always do your research and get all the right facts before disregarding your options.
(Image Courtesy of: www.apxsolar.com)
{ 6 comments… read them below or add one }
what I am considering at my new house is a grid-tied system to take advantage of federal+state tax incentives PLUS building in components to isolate from the grid and charge my plug-in car directly off DC to avoid invertor losses AND/OR use the car (12 kWhr onboard) to feed the invertors to power the house at night if need be. This way I could get double duty from my car battery pack, full financial advantages of grid-tie, and security of off-grid backup……..
While it is certainly true “off-grid” is not for everyone, I have to disagree with the entire statement: “(batteries) brings up the overall cost of the system, are bulky, unreliable, and are not as environmentally friendly.”
Truth be told, the bulk is something you may have to deal with every 5-10 years; the cost of batteries is far less than the over-sized solar arrays I have seen on most “on-grid” homes; and the fact you’re off the grid and not utilizing a coal plant at night is far more environmentally friendly.
An off-grid home will watch its energy usage very closely, while an on-grid home need not worry. With that, most off-grid homes use a fraction of power that an on-grid homes uses.
An on-grid home produces power during the day when no one is home and in the evening consumes from the power plants just like any typical home.
To think of the grid as “storage” is somewhat misleading. These on-grid homes are not in fact re-using the same electricity created earlier that day and it’s because electricity production is just like a waterfall; if you don’t harness the energy of the falling water, it just goes away. Power plants run 365 days a year whether you choose to flick on a switch or not.
Another point I’d like to make is that by law, electric companies must make a certain percentage of electricity using alternatives. On-grid solar helps fill that quota and it never ceases to amaze me when I see entire rooftops completely covered in panels. Most of these homes could do away with a 1/3 of the panels, buy batteries, cut the cord to the utility, and have a little money left over all while easily supplying their own power.
Don’t get me wrong here, I whole heartily endorse all solar. I would just like to keep the record straight.
For those of you trying to decide whether to stay on-grid or go off, remember, it is possible to be on-grid with battery back-up. Probably the best of two worlds.
So until utility power is produced largely by sustainable alternatives, C02 pound for Co2 pound, off-grid (for now) is “greener” than on-grid.
Dave, thanks for the comment. I agree with you whole-heartedly, and can see how you think “off-grid” users are more conscious about their electricity than “on-grid” users. For home-owners who go solar purely from an economical standpoint, it’s hard to justify the up-front cost of batteries for them.
I have a grid-tied solar system, and would like to know what it would take to run the system in the case of a power outage. It seems power outages are getting more and more common. If I get a generator, could I run it at the same time as the solar? Can I tie my solar into a disconnect panel? Do I need a 240V generator, or can I get a small, long-running 120V generator?
You can run a generator at the same time as the solar panels. As far as solar being tied into disconnect panels and being able to take it “off-grid” during a power outage is a question that is best suited for a solar installer. A 120V generator should suffice unless you have a need for 240V?
Since your system is grid-tied, your system itself cannot run when the power goes out. You should be able to get a generator and run it if your power goes out. Your solar installer should be able to help you pick out the right generator for your house or system.