Solar power has become quite popular lately, coming in two main varieties: Grid-tie and off-grid. Which one is right for you?
I've been living off the power grid for almost 25 years and am here to walk you through this important topic. By the end of this post, you'll be able to decide for yourself whether your circumstances are best suited to a grid-tie or an off-grid solar power system.
First, let us take a quick look at some pros and cons:
|Grid Tie Solar System Pros
|Off Grid Solar System Pros
|Typically lower cost (if no battery backup)
|Independence! - Power company outage has no impact on your water or other systems
|Typically little to no maintenance (batteries are the main source of maintenance)
|Reduces "red tape" that comes from connecting to the grid
|No power usage concerns (the grid is your battery)
|May be cheaper than running power into remote properties
|Can greatly reduce your monthly power bill
|Can eliminate your monthly power bill
|Grid Tie Solar System Cons
|Off Grid Solar System Cons
|Conventional grid-tie leaves you with no power during a blackout
|Is often more expensive, all other things being equal
|If you add battery backup, the cost goes up, and grid-tie loses some selling points
|Can require more maintenance than grid-tie (maintenance-free batteries reduce this)
|Potentially more regulations since it is connecting to the power grid
|To be economically feasible, requires you to choose appliances carefully and manage power usage
|You are at the mercy of the power company to a great extent
|If you don't manage power usage properly, there's no grid for backup (run the generator)
Now, for a bit more detail. The first one we will look at is the Grid-tie power system and then we will look at what an off-grid power system looks like.
Grid-Tie Solar Systems
For a variety of reasons (environmental, economic, etc.) many people choose this route. Typically this starts by connecting the home to the local power company’s power lines. The home uses power and the meter spins. At the end of the month, you receive a power bill for the electricity you used.
Up to this point, everything is “normal”. Here is the difference. Grid-tie systems use the energy produced from the homeowner’s renewable sources to offset the power purchased.
Basically, it consists of installing a solar panel array (often on the roof of the house). The electricity generated by your solar panels is then directed into your home for use or on to the power grid.
During times when the solar system is producing more power than your home is currently using, the power meter essentially spins backward, selling power back to the power company. Then you get a credit on your power bill. When the power produced is less than your current usage (i.e. at night or on cloudy days), then the power company “sells” you the power you need and you receive a bill in the mail.
The Advantages of a Grid-tie system
The goal of most grid-tie systems is to greatly reduce or eliminate your power bill. You'd want to install enough solar panels to accomplish that depending on your current budget.
Conventional grid-tie systems are typically less expensive (per kWh of power produced) than off-grid systems. The reason? There is no need for equipment to store excess electricity. The power company basically becomes the storage system, selling you power whenever your system is not producing enough.
The downside of a conventional grid-tie system is that when a power outage occurs, you still lose your electricity like everyone else. The solar system automatically shuts down during a power outage so that it doesn't electrocute a poor lineman who might be trying to restore power to your area.
Having said that, it is true that many modern grid-tie systems can be set up with a small battery backup to provide power during blackouts. But this increases the cost of the system, and most on-grid homes are not set up to be off-grid and would plow through any moderately-sized battery bank in record time. So the battery backup systems basically give you a short tether to make it through quick blackouts with only a portion of your home operational. In our opinion, if you go to the expense and effort of setting up a full battery system and making your home off-grid ready, why not just go off the grid?
Off-Grid Solar Systems
An off-grid solar power system is completely independent from the power grid. It produces all of its electricity. When its power sources are generating power (solar, wind, hydro, fuel-powered generator), they are powering the home, and any unused power is stored in a battery bank for times when you aren't producing as much.
An inverter/charger works to convert the power from your batteries or solar panels into usable power in your house, just like you would if you were on the power grid. With the exception of solar panels, you wouldn't know the difference practically in your home. You'd plug in your kitchen appliances, computer, and phone charger into an electrical outlet just like you would normally.
There are some additional components we won't get into on this post, but these are the most basic components of an off-grid solar power system:
- Solar panels (and/or other power sources) - to generate electricity
- Battery bank - to store any unused power
- Inverter/charger - to transform the solar or battery power into regular household current, just like you'd get from the power company
The Advantage of an Off-Grid System
The #1 advantage of an off-grid system is the independence it provides. When your power company is experiencing a local or regional blackout, you are completely unaffected. It's awesome to find out days later about a power outage in your area that you weren't even aware of!
All other things being equal, an off-grid power system costs more than a conventional grid tie system, since there are no batteries with a conventional grid-tie system. However, there are other factors. For instance, most off-grid power system owners choose to become more energy efficient. Therefore, they don't need to produce as much power (or build as large a system), as they would have if they had gone with a grid-tie system. So I have seen a number of off-grid systems that were significantly cheaper than a typical grid-tie system. If done properly and economically, even an off-grid system should pay for itself and end up saving money in the long run. How long this takes will depend on your energy consumption, how economically your system is designed, and the price of energy in your area.
One other factor to consider is the cost of running power lines to a remote property. If you find yourself in that situation, it could cost tens of thousands of dollars for the power company to get you connected to the grid. While this cost varies depending on the distance from existing lines and installation difficulty, I have heard of an $18,000 quote for running power to a location around 1 mile from the power lines; another quote was approaching $50,000 to run the power lines several miles.
One final clarification regarding energy efficiency. We live very normally here. We didn't substantially change our lifestyle to be more power efficient for our off grid system. Instead, we focused on finding equipment that was more power efficient. That's the key to thriving in off-grid success. You don't generally have to do without. It's about choosing wisely.
Because an off-grid system enables one to become truly energy independent, that is what we highly recommend. Are you ready to take your home off the power grid?