Can I Go Off the Grid with Solar Batteries?

| 10/8/2015 3:23:00 PM

Tags: energy, solar power, energy storage, utilities, off grid living, Vikram Aggarwal, Massachusets,


Newer, more efficient solar panels and inverters have been in the news recently, but advancements in solar technology aren’t limited to standard equipment. Energy storage is also moving closer to mass-market adoption, and more installers are offering solar batteries (a.k.a. solar-plus-storage) as an option for homeowners. Solar-plus-storage systems include a battery that captures and stores the excess energy generated by the system’s solar panels, opening up the possibility of going “off the grid” – a tempting proposition for homeowners who want to sever their connection with utility companies by using renewable energy.

Since solar battery technology is relatively new to the solar market, there isn’t significant solar storage capacity deployed in the U.S. That won’t be the case for long though: between utility and residential installations, solar battery deployment is expected to increase twelve times over in 2015. As solar batteries become cheaper and more accessible for homeowners, more people are wondering, “Can I use solar batteries to go off the grid with my solar panel system?”

What Does it Mean to go “Off the Grid”?

Installing solar panels on your roof doesn’t mean that you’re off the grid. Most solar systems can’t consistently generate enough electricity to be a home’s only power source, which is why the vast majority of solar homeowners maintain a connection with their utility company.

When you generate more power than you use, your utility gives you a net metering credit on your electricity bill. When you need to, you can then spend your credits to supplement your solar power with electricity from your utility company. If/when you don’t have credits, you’re simply charged the going rate for electricity at that time. For the average solar homeowner, this process typically means you’re generating more power than needed during daylight hours, and less than needed at night.

If your solar panels can generate over 100% of your home’s electricity needs, then the credits you receive from your excess power generation could theoretically cover the costs of electricity needed in low-sunlight periods. However, this process requires that your home still stay connected to the grid. By truly going “off the grid,” you would need to sever your connection to your utility company. By doing this, you would lose the ability to purchase electricity from your utility in low-sunlight periods. This is why your home would need solar batteries installed to stay powered at night.

10/9/2015 6:06:44 AM

There is no such thing as "solar battery". That implies the actual photons can be stored for future use. I'm sure we'll get there some day, but not in our lifetimes. . There ARE various battery chemistries that have been around for years, decades, and in the case of a few chemistries for centuries. They all just store electrons via chemical reactions. Most solar systems use flooded lead-acid deep cycle batteries since they are the cheapest option (relatively). Some larger pre-packaged batteries with alternative chemistries have been marketed lately (Tesla being one promoter) as useful for home storage but they just have marketing hype. They are also not as cheap dollars-per-watt as flooded lead-acid. But they do have the advantage of low maintenance so there is some benefit for the extra money spent. . While you covered the fact that some off-grid systems maintain a grid connection for backup, you didn't cover the usual backup scenario, which is using a generator once the battery has been depleted. Since most off-grid systems were built because there is no grid connection to begin with, a genset is the only option. If a grid connection is available it is the better option for backup - for now. Grid reliability and cost may change that eventually.

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