can i go off the grid with solar

Can I go off the grid with solar batteries? Excess solar energy explained

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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 and solar panel battery banks (a.k.a. solar-plus-storage) as an option for homeowners.

Solar-plus-storage systems include a battery that captures and stores the excess solar energy generated by the PV system, 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. 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?”

Find out what solar + storage costs in your area in 2021

What is an “off-grid solar 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.

Can I use a solar panel battery bank to store my excess solar energy?

The battery storage technology that makes it possible to go off the grid does exist. If you install sufficient battery storage along with your solar PV system, you can store any excess electricity at the time of generation and then draw from it as needed later. You may be hearing talk of using “solar panel battery banks” as a means to harness massive amounts of storage capacity in order to become completely independent of the grid. Because off grid projects involve sizing enough energy to power your entire home, you’ll hear battery bank terminology used when a contractor is trying to estimate a total wattage for a combined battery system. In theory, you can find do it yourself methods for storing mass amounts of renewable energy with these connected battery arrays. In practice, however, going off the grid is more complicated than you might think, particularly if you live in an area with significant climate variation.

Residential-scale solar batteries on the market today can store the energy generated during the day for your home to use at night. This can be particularly beneficial in areas where net metering caps have been reached, or in areas where utility companies don’t have good policies for compensating homeowners who generate excess solar electricity.

The trickier proposition is capturing excess electricity generation in the summer, when solar power generation is highest, to use in the winter, when it is at its lowest. According to EnergySage marketplace data, the average solar shopper offsets 92.5% of their electricity use with their solar system – a significant amount, but not enough to go off the grid. Preventing total power loss in the event of a winter snowstorm or extended overcast days would require a lot of storage capacity, a very large solar panel system, and a significant financial investment to install.

While it is technically feasible to go off the grid with solar batteries, it’s rarely cost effective. In some places, particularly in remote areas, off-grid solar battery systems are the best (or even the only) option. More often, solar shoppers maintain their connection with their utility company, even when they choose solar-plus-storage solutions.

The good news: with or without storage, solar panels can still save you money

While you might not be able to completely go off the grid, solar panels are still a strong investment, and solar battery technology is becoming cheaper every year. With $0-down solar loans and solar leases, you can save money on your electricity bills as soon as your solar system is up and running, and you may even be able to get rebates or production-based incentives for switching to solar energy.

To learn more, use a solar calculator to get an instant estimate of what solar can do for your home. And as with any other major purchase, be sure to comparison shop for solar equipment and financing options before selecting the ultimate installer you plan to use.

This post first appeared on Mother Earth News

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37 thoughts on “Can I go off the grid with solar batteries? Excess solar energy explained

  1. William Costello

    Try dipping your toes in reality. Your article is so misleading about batteries as to be criminal. You need to have a battery bank big enough to power your home for at least 14 hours without draining your batteries below the 75% level. You need to have a solar panel array big enough to recharge your battery bank at 25 amps per string (minimum) while powering all loads during the day. Being connected to the grid with this system removes the need for a backup generator sized to recharge your battery bank in the case of extended lack of sunlight strong enough to power all your loads. In the case of an “off grid” system, a generator is required. I strongly recommend a Natural Gas or Propane fueled generator for this purpose. Storing power in the summer for winter use is not the function of a reasonably sized battery bank.

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  2. Bob Reed

    Will – It sounds like SoCal Edison is charging you the retail price for any power you consume from their grid and paying you the wholesale price for any power you supply to them. To put it more directly, it sounds like *if* you had consumed that power instead of generating it, you’d have paid them $636 but since they got the power from you, instead they’ll pay $85. This gives you some idea of the markup in that market. Being a utility is apparently the next best thing to printing money on your own press.

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  3. Jaymie Martinez

    Be sure to research how your electric company handles solar! Ours penalizes solar customers with an additional fee for use of energy when panels aren’t producing…will not use the excess “bank” for these “peak” hours.

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  4. Will

    I just want to add that the power companies hate solar. I just passed the one year mark on have solar panels and Tesla battery in my home. I rarely draw any power from the grid. The only time I used grip power was in the summer when I ran the air conditioning. I have Southern California Edison as my provider and they will give you a bill for every month, regardless if you draw any power. Furthermore, they show you your negative bill though the year. At the end of this year my bill showed -$636. They also make it a point to say you can get your excess charges refunded, plus the cost of the power you generate. Well, at the end of the year, you are expecting to get a refund the size of the amount shown on your bill. Guess what? They just arbitrarily pick a whole sale price for the power you generate, and give you that credit. So my -$636 became a refund of $85.

    Edison, and California are the most corrupt, incompetent, worthless, organizations on the planet. If you can go off the grid, and not pay Edison or California any additional money, I strongly encourage you to do it. Everything in California is a deceptive, corrupt mess.

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    1. Jason

      Maybe read their tariff documents? All utilities have to publish these, and Edison is governed by the CPUC and must adhere to NEM 2.0. These details were available, and you and/or your installer should have researched them and been aware. The numbers they pick aren’t random.

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  5. Begol

    Hi… I am from a monastery in the desert of Egypt and we use solar energy only during the day and generators of electricity during the night. But with any batteries or system You suggest that I use it for solar energy at night

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  6. Solarman

    Sorry, Robert in Australia, the politics force alternative prices one way, then another. It seems to depend on who’s in power at the moment. That being said, Australia seems to also be the country with the highest per capita solar PV installations on residential homes.

    You have already shown an interest in alternatives, so have you done an analysis of your average monthly electricity needs? There are so many variables, one has to define, then compare with past electricity usage to see if it is possible. When all is said and done, you could have calculated your energy budget and designed a system that works very well for you. Then along comes a daughter or niece with a 1500 watt hair drier that screws up your daily budget in 20 minutes.

    I wish I could help you more with that, alas what I’ve noticed around the World is the “typical” daily demand from the many countries. Africa and India, solar PV with storage batteries only needs a couple of solar PV panels that could generate 1.5 to 2KW of power per day. The entrenched industrialized countries like the U.S. runs from an average 30kWh to 48kWh per day or around 1.25kWh to 2.0kWh continuous during the 24 hour period. In south Australia, I imagine there are the 43 degrees Centigrade days and nights without temperature relief. This is the American South West during the summer months. This is where one ends up using air conditioning 24/7 to stay comfortable. During those summer months, it is not unheard of using 7.56MWh for the month, which is why $1300 a month electric bills are common in the desert. In reality that’s something like a 42kW peak energy generation from solar PV or some other source (wind, micro hydro, etc.). It is becoming more feasible to over build one’s solar PV system, store excess energy during the day in an energy storage system, then at night use the stored extra to offset the utility’s practice of evening “demand charges”. Late at night and early morning, use the arbitrage algorithm in the energy storage system to charge up the battery for the morning peak, when solar PV isn’t making enough power just after sunrise.

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