How Does Off-Grid Solar Actually Work?

How Does Off-Grid Solar Actually Work?

Estimated reading time: 6 minutes

Off-grid energy solutions have caught the attention of people across the country due to recent power outages. Off-grid solar systems appeal to consumers primarily because of their reliability—it can be reassuring to know that you are self-reliant.

Blackouts in Texas

As the homeowners’ interest in off-grid solar systems grows, it is important to clear up some common misconceptions about off-grid. For example, just because you have energy storage doesn’t mean that your solar system is off-grid—if you have a solar battery, you would still be on-grid unless you completely disconnect from the grid and rely solely on your panels and battery storage.

To better understand the realities of off-grid living, we’ll discuss the following:

Why off-grid?

For some, off-grid is a necessity; people living in remote areas with limited or no access to the "local" power grid can definitely benefit from more reliable access to electricity.

Off-grid energy also appeals to those with life-support systems, important remote work, or any other serious dependence on electricity. 

While the idea of energy self-reliance isn't new, interest in off-grid has expanded as a wider range of people has recently experienced the inconveniences and dangers of going without power.

For example, in February 2021, unexpected blizzards and icy temperatures shocked Texans. Days and days without power pushed many individuals' situations from uncomfortable to deadly.

Wildfires in California and other states also significantly affect electric utilities because the fires can threaten portions of the grid and the stability of the grid itself. Naturally, these threats affect customers' supply of electricity. 

California power outages

Since these natural disasters and energy dilemmas don't seem to be going anywhere anytime soon, people are looking to change their sources of energy since they can't change everything about their situations. 

While the idea of off-grid solar appeals to many, people in the market for solar sometimes make the assumption that solar panels are an off-grid solution independently. This, however, is not the case--next, we'll discuss why.

What is off-grid solar?

Let's first define off-grid—this will help clarify its purpose and possibilities.

As was mentioned earlier, for a solar system to technically be off-grid and fully reliant on solar energy, it needs to completely disconnect from the grid.

However, this process isn't simple or cheap.

It's important to recognize that many states discourage off-grid living through local laws and regulations. Most solar installations connect to the grid for this reason and because grid connection is financially the best choice for most.

If a solar owner is cleared to go off-grid, then he or she will need to have solar energy storage, and solar batteries are expensive. 

When you're connected to the grid, net metering allows you to have constant access to electricity, even if your demand at the moment is higher than your panels' production. 

Net metering agreements are formed between utility companies and solar owners. When a solar system is connected to the grid, its excess energy generation is sent to the grid, and then solar owners pull energy from the grid when needed. 

Solar Net Metering

This is important because peak solar hours are typically in the afternoon, and households generally don't use much electricity during that time. The excess energy being produced needs to go somewhere if there is no battery storage, so it is sent to the grid.

However, once people are home from work and school later in the day, they're using appliances, turning on lights, etc. Unfortunately, there is usually less energy production during this time, so your panels' production may not fill your needs. Instead of going without electricity, you can pull from the grid.

What are the differences between energy storage and net metering?

Many locations have "one-to-one" net metering policies, meaning that power companies will allow you to later use the same amount of kWh that is sent to the grid (which is just like a battery but without the efficiency loss).

For homeowners with these kinds of favorable net metering policies, off-grid doesn't make financial sense because it will cost much more to purchase a solar battery.

1-3 batteries (10-30 kWh of storage) could certainly cover the majority of most people's energy usage. This would fulfill the same basic purpose of net metering and spread out all the energy generated into the evening and early morning when the sun is not shining.

However, for an off-grid system, you would need enough capacity to have your needs covered through a winter storm. While 1-3 batteries would allow you to be 90% + (weather permitting) energy independent, off-grid living typically requires more of an investment to guarantee energy in case of a situation where your panels don't produce for several days.

How do you size an off-grid solar system?

If an off-grid solar system makes sense and is possible for your situation, here is how you can size your system:

The rule of thumb when designing an off-grid system is to have 2-3 days worth of storage. To calculate this, simply look at your monthly kWh usage and divide by 30 to get your daily usage rate. Then multiply by 2-3 (days), and that is your storage need. 

For example, if someone is using about 2,100 kWh a month, on average, his or her usage will be about 70 kWh a day. Multiply that by 2.5 (let's say the home is in UT, which is relatively sunny), and that equates to 175 kWh of needed storage. At about $1,000/watt, that's $175,000 of standard lithium-ion batteries.

For off-grid to be worth its current price, most customers would probably need there to be a pressing reason. Most people looking for true off-grid solutions do so for mountain homes or other remote locations where grid tie wouldn't even be an option if they wanted.

Off-grid homes are usually smaller, and most will opt for lead-acid batteries over lithium-ion. Because lead-acid batteries have shorter lifespans than lithium-ion, they are considerably cheaper.

Batteries Available With Project Solar

At Project Solar, we currently do not install completely off-grid systems. However, our customers can certainly take advantage of net metering or purchase solar batteries if preferred.

Solar batteries are not required for our solar systems and we rarely recommend them because of the reasons mentioned earlier. 

However, if energy storage is possible and a priority for you, we offer the Enphase IQ 5P batteries and the Tesla Powerwall 2. 

We also offer the grid-independent Power Bank with optional Expansion Packs.

Check out Project Solar's free quote calculator for an estimate with or without batteries.

Project Solar solar system


Off-grid solar is an exciting possibility that could make energy much more accessible and reliable for a certain group of customers. However, it is not for everyone, so it is important to assess its costs and limitations.

Back to blog