Off-grid solar systems: An introductory guide
Off-grid solar means meeting all your energy needs from the power of the sun — with no help from the electrical grid. To make this possible, you need to install a solar power system paired with an energy storage system, like a solar battery, at the site of power consumption (your home).
The idea of cutting all connections with the utility grid in favor of generating solar power yourself was once a fringe concept, however, in recent years, it has emerged as an increasingly popular way to generate power.
Its spread has been aided by major technological advancements in solar panels and storage; they are both far cheaper and more efficient than they were even just a decade ago.
In this blog, we’ll cover:
- What is an off-grid solar system?
- Reasons for living off-grid
- Uses for off-grid solar power
- Off-grid solar equipment
- Sizing an off-grid solar system
- How much does off-grid solar cost?
- Advantages of off-grid solar
- Disadvantages of off-grid solar
- Is off-grid solar right for you?
Pictured: An off-grid home. Image source: energy.gov
What is an off-grid solar system?
While many people think only of solar panels when they hear “off-grid solar”, the reality is that you need to add many other components to get a functioning off-grid PV system.
A complete off-grid solar system is one that has all the necessary equipment to generate, store, and supply solar energy onsite. As off-grid solar systems operate without a connection to any external power source, they are also referred to as “standalone solar power systems”.
Batteries, however, are costly — much more so than the solar panels they are paired with. The need for ample battery storage in off-grid solar systems makes them much more expensive than grid-tied solar systems.
Why do people decide to live off the grid?
You may be wondering, why exactly do people opt for off-grid solar?
As part of a holistic off-grid lifestyle
For those seeking a sustainable off-grid way of life, going off the grid for their energy needs is often a key component. While power can be generated through other means, including by wind and hydropower, off-grid solar is typically the cheapest and most convenient option for renewable energy.
The next-best option when the grid is unavailable
There are many cases in which it is impossible to access the grid, for example, if you’re camping, or traveling in an RV. In other situations, a grid connection to a remote location like a cabin may be possible but so expensive as to be completely impractical. By contrast, sunshine is available everywhere.
In other words, off-grid solar is for those who can’t — or don’t want to — connect to the electricity grid.
What is off-grid solar power used for?
One of the biggest advantages of solar as an energy source is its scalability and modularity, which is the degree to which a system’s components may be separated and recombined for flexibility and variety in use.
It works at all levels, from small devices such as solar phone chargers, all the way up to a system that can power a factory.
Here are some of the most common applications of off-grid solar:
- Providing a charge to a portable phone or tablet charger
- Powering the appliances in an RV
- Generating electricity for small cabins
- Powering small energy-efficient homes
If you’re wondering about regular family homes with solar panels in the suburbs: it is actually quite rare for them to be off-grid. The reason for this is that off-grid solar systems always cost much more than equivalent grid-tied systems.
What equipment does an off-grid solar system require?
Here’s a list of all the equipment required for a functioning off-grid solar system:
- Solar panels
- Solar charge controller
- Solar inverter(s)
- Solar battery
- Mounting and racking system
- Junction boxes
Electricity from the solar array flows to the charge controller - from there it is either sent to the battery for storage, or to the DC-AC converter (aka inverter) to supply power to the home.
For more information about each of these components, check out this blog on solar panel equipment.
How to size an off-grid solar system
Deciding on the size of the system you need is an early and absolutely crucial step when it comes to installing an off-grid solar system.
It will affect the kind of equipment you need, how much work the installation will involve, and, of course, the total cost of the project. Solar setup sizes are based on the amount of power the system needs to provide.
There are two different ways to figure out the number you need, and they are based on:
- Your current usage
- Load evaluation
Basing solar setup size on usage
You can use this option if your aim is to maintain your current lifestyle as you switch from grid-tied to off-grid solar. To do this, you can simply refer to your monthly power bills to determine your electricity usage in kilowatt hours.
You can then size an off-grid system of that size, although you’d want to go a bit bigger — say 10% more — to allow for solar inefficiencies.
Basing solar setup size on load evaluation
The second option is to perform a complete load evaluation to determine how much power you’ll need.
In this method, you list out all the appliances you plan to use and how many hours you’ll be using each of them. This allows you to calculate the power consumption of each appliance, as well as your total power consumption over a day.
Knowing how many kWh in a day you’ll use will allow you to size your solar panel array, as well the solar battery storage.
You’ll also need to think about how many appliances you might run simultaneously. This will help you calculate instantaneous wattage requirements, which you need to know in order to size the inverter properly (the inverter runs the AC loads).
When it comes to batteries, you’ll need to decide how much energy storage you want. Do you want to cover usage for just one day, or do you want to have extra backup capacity?
When it comes to solar battery backup, the rule generally is you'd want enough storage to cover at least 2-3 days of usage during the highest usage time of year.
Figuring out the sizes of these three crucial components — the solar panels, inverter, and battery storage — is usually enough information for solar equipment vendors to customize a complete off-grid kit for you.
How much does an off-grid solar system cost?
The prices of off grid systems range from about $50 (for a phone or tablet charger) to tens of thousands of dollars. That’s because off grid solar has such a huge variety of applications.
If we talk specifically about off-grid solar kits that can power an entire home, then prices range from $12,000 to $50,000.
You can get an idea of pricing from the table below; it shows popular off-grid kits for different end-use requirements:
|Name||Peak output||Battery||Price*||Suitable for|
|Hiluckey||5 W||92.5 Wh lithium polymer||$47||Phone and tablet charging|
|WindyNation||400 W||3.6 kWh lead acid||$1,690||RVs, camping|
|AltE||1.83 kW||13 kWh lead acid||$12,046||Cabin, tiny home|
|AltE||4.88 kW||25.9 kW 48V lead acid||$15,160||Small home|
|Wholesale Solar||11.34 kW||55.2 kWh 48V lead acid||$35,576||Mid-size home, farm/ranch|
|*Prices as of June 1, 2020|
Please note that the costs mentioned are only for the off grid solar panel kits, i.e. just the equipment. If you use a professional solar company for installation, there will be additional charges for labor; whereas with a DIY there may be some extra costs for permitting and tool requirements.
Learn more: 11 step guide to DIY solar
The impact of battery type on cost
With the exception of the Hiluckey phone charger, all of the kits above include AGM lead acid batteries. AGM (Absorbent Glass Mat) batteries are a popular choice for off-grid solar systems because they are low maintenance, convenient, and relatively inexpensive as compared to lithium batteries.
The advantages of off-grid solar
Over 300,000 homes are believed to be using off grid power sources for their energy needs.
Here are a few reasons why some Americans choose to live off the grid.
Freedom from the grid
This is the primary reason why people in blackout-prone regions are interested in off-grid solar. When connected to the grid, you are dependent on an external supplier — the utility company — for all your power.
When the grid shuts off, so does your power supply. This dependence doesn’t seem to be a problem until you are hit with blackouts and power failures, as those who suffered through the California blackouts of 2019 can attest.
It’s good for the environment
Going off-grid reduces carbon emissions. Since most of the electricity supplied through the grid comes from burning fossil fuels, producing your own power through renewable resources (solar, wind, hydro) drastically reduces your carbon footprint.
Encourages a more energy-conscious lifestyle
When you’re connected to the grid, it’s easy to be unaware of your power consumption habits — you consume electricity, pay the bill when it comes, and that’s that. It disconnects you from where the electricity is coming from and where it’s being used.
Your attitude when it comes to power changes completely when you go off-grid. In order to ensure you don’t run out of electricity, you will have to closely follow your energy generation and also re-evaluate and rationalize your energy consumption.
Often the only feasible option
When you’re seeking to power a building in a really remote location - say a hunting cabin out in the woods - there’s a good chance there’s no grid to connect to at all.
If you contact the utility for a connection, they will probably tell you that you are out of their coverage area. Alternatively, they could offer to lay the wire to connect you to the grid — but only at an astronomical cost.
That means that you’ll have to produce your own power. You could use a backup generator, but fuel for it is expensive, while renewable energy like hydropower and wind aren’t available most places. This leaves solar as the only practical option for off-grid power.
A beautiful off-grid A-frame cabin in the Catskill Mountains. Image source: Chris Daniele via OffGridWorld
The disadvantages of off-grid solar
In spite of some great benefits, there are several valid reasons why the vast majority of US households choose to remain connected to the grid when they install solar on their homes.
Some key issues with going off the grid include:
Off-grid might actually be illegal where you live
While installing solar panels and generating your own electricity is gaining traction across the US, there are some counties that have made it illegal to completely unplug from the grid. Such legal restrictions related to going off-grid are generally more common in metropolitan areas than in more rural areas.
Off-grid solar systems are expensive
A solar panel setup that supplies all the energy needs of a home tends to be very expensive.
Compared to a grid-connected solar system, an off-grid solar system requires more panels, an inverter with a higher voltage capacity, and a large amount of solar battery storage.
And since there’s no grid to fall back on, you will want to purchase a gas or diesel-powered backup generator, and these are very expensive to run. This also adds greater urgency when repairing faults in your off-grid system because generators cannot be relied upon for too long.
Off-grid solar is time-consuming
Making the commitment to produce enough power to meet all of your household’s needs is an extremely challenging task.
A fairly advanced understanding of how electricity works is required. Because generating power is an exact science, you will have to spend time calculating the precise amount of power that needs to be generated, based on your energy usage patterns.
Time will need to be spent ensuring you are keeping power waste at a minimum. And because power generation can be unpredictable, you will have to constantly monitor your power supply.
You also must learn about the equipment used to generate power and be capable of fixing any and all faults.
No SGIP rebate for off-grid solar in California
California California’s Self Generation Incentive Program (SGIP) is one of the largest battery storage incentives in the country. Eighty percent of the incentive's budget is allocated for battery storage.
People can save thousands of dollars on batteries with the SGIP rebate, especially if they live in fire hazard districts. But the catch is that SGIP is only available for grid-tied solar systems with battery backup — and not for pure off-grid solar systems.
There are more convenient alternatives for those seeking backup power
The biggest reason why going off-grid may not be for you is because there simply is a better alternative.
The easiest and most efficient way to protect yourself from blackouts, while saving money on your power bills and helping the environment, is by installing a grid-tied solar system with battery backup.
These ‘hybrid’ systems, which use battery solutions such as the Tesla Powerwall, are cheaper than off-grid systems and also qualify for incentives such as the SGIP rebate.
Off-grid solar entails major lifestyle sacrifices
Talk to anyone with an off-grid solar system, and they will tell you the same thing: relying on off-grid power requires you to completely reevaluate your relationship with energy.
The high cost of off-grid solar means homeowners are forced to install relatively small systems. The amount of power available is often further limited by inclement weather: a cloudy day may result in power output reductions of 50% or more.
Running out of power leaves you in a bind. You will either have to wait for the sun to come out again, or generate power using a backup diesel generator (if you have one). The first option is very inconvenient, while the second is very costly.
These constraints can affect every aspect of your life. Many off-grid folk, for instance, say the need to conserve power means they have to economize on water as water pumps consume a lot of power; this means short showers and less frequent flushing. Air conditioning, an even bigger power guzzler, can only be used for limited periods, if at all.
Without careful management of your off-grid energy usage, you could find yourself running out of power when you need it. Image source: AP
Is an off-grid solar power setup right for you?
Off-grid solar is the most convenient energy source when it is hard (or impossible) to access the grid. It’s hard to imagine, say, a camping enthusiast forgoing solar in favor of a generator that is heavy, noisy, and requires costly fuel.
It is also usually the best option to those committed to a low carbon footprint, sustainability-minded lifestyle. Other renewable energy sources, such as wind and hydropower, aren’t just more expensive, but they also require access to a reliable wind and water supply.
On the other hand, if you are a typical homeowner living in or near a city or town, then off-grid is almost certainly not for you.
This is because off-grid solar systems for homes are expensive and thus rarely yield any savings over utility power. Furthermore, the high cost of off-grid solar means homeowners are forced to install relatively small systems; the limited power they provide imposes major lifestyle sacrifices on the home’s residents.
If it’s financial savings you’re interested in, then look at grid-tied solar systems instead. They are the cheapest way to go solar, and in many states they can result in savings of $100,000 or higher. And having a connection to the grid means that you’ll have consistent access to all the power you need.
You can learn more about how grid-tied solar systems work here.
If, however, getting a battery backup like the Tesla Powerwall is a priority for you, then consider hybrid solar systems. Hybrid solar systems are grid-tied systems which also have batteries. While hybrid systems are more expensive than simple grid-tied systems — and thus offer lower savings — they are still far cheaper than an off-grid setup.
You can check the costs and savings of a grid-tied solar panel system by entering your address into the calculator below.
Author: Zeeshan Hyder | SolarReviews Blog Author
Zeeshan is passionate about promoting renewable energy and tackling climate change. He developed these interests while studying at beautiful Middlebury College, Vermont, which has a strong focus on sustainability. He has previously worked in the humanitarian sector — for Doctors Without Borders — and in communications and journalism.