Aside from all the technical elements involved when creating and installing a solar PV system in your home, the first question that should be asked is whether you are going off-grid or on-grid.
The on-grid or grid-tied system means you are connected to the grid and can draw and return power to the grid. Off-grid means you are completely independent of the utility grid, and only the power you generate can be used to power your home or business.
This is not as clear-cut as it seems, as each has pros and cons. Still, it depends on your motivation for installing a PV system. Whether you want total independence or if you still want a little failsafe will determine whether you go off-grid or on-grid.
The On-Grid Solar Power System
On-grid has some major benefits, especially if you don’t want to spend a lot of money on storage, as this can add several thousand (if not more) dollars to the cost upfront.
1. On-Grid Systems Don’t Need storage
When you are on-grid, you can use your PV system to power your home or office during the day as electricity generated by the solar panels flows to your home and keeps all the devices and appliances running.
Once the sun goes down and the electricity generation slows from the panels, you can switch to the grid supply for the night. If you want to use your PV system to power your home at night, you will have to add batteries to do this.
Battery storage is expensive, and while the lead-calcium batteries are around a quarter of the price of the far superior lithium-ion batteries, adding enough storage for an average home will add up and add up quickly.
2. You Can Get Net-Metering When You Are On-Grid
Another exclusive benefit to being on-grid is that when your system produces excess electricity, it can be sent back to the utility through the grid-tie. You are credited on your utility bill!
When you need to use electricity from the grid, if the solar system hasn’t produced enough or it’s been poor weather, you can switch over to the grid and use power and only pay for that usage once it exceeds your available credits.
If you are off-grid, you cannot get net-metering.
3. You Always Have Access To Electricity With An On-Grid System
While the idea of being power-independent sounds great, you need to consider the status quo of your electricity supply before you opt for off-grid.
Many homeowners want to cut their energy costs as much as possible, and this is often the motivating force behind the impulse to install a solar system. It’s then the choice of some dependence on-grid or independence off-grid.
But, that independence comes with a price, and that price is that you don’t have any access to power other than what your PV system produces and stores when you are off-grid.
Being on-grid gives you that peace of mind knowing that it’s available then and there should you need power. You don’t need to wait for the morning for the sun to start charging up your power supply.
Not only that, but if you have a spell of bad weather for a few days and your batteries are depleted, you have to wait until the weather clears before you will get any power to your home or office.
Do You Get Bills With An On-Grid Solar Power System
Yes, you will continue to receive utility bills as you will still (at some point) require grid support. Still, your bills will be much lower than usual, especially if you live somewhere in the more temperature zones in the US, where the lower average temperatures make solar panels more efficient.
You would see some usage (unless you have credits through net-metering) and some other connection or service charges, but certainly not the usual usage and kWh costs you normally see.
What Happens When The Grid Goes Down
Here is where the grid-tie system fails as solar systems have to be shut down when the grid goes down as sending power back into the grid while workers are fixing it is dangerous, and this is required by the Underwriters Laboratories (UL1741).
If the supply grid goes down during the day, and your system is generating electricity, then you’ll have coffee while most people don’t! At night though, you will be in the dark like everyone else, which spurs many homeowners and business owners to add storage to their solar power system.
Off-Grid Solar Power Systems
Off-grid systems have some strong arguments, but let’s start with the disadvantages first.
1. Off-Grid Systems Don’t Have A Backup
Firstly, you don’t have a backup if your system hasn’t stored, made, or produced enough electricity to run your home or office. So if there is bad weather such as snowstorms or heavy rain, then very little sunlight will reach your panels, and your supply will be very low or non-existent.
If this happens, you won’t produce enough power to run your appliances and devices nor will you convert excess electricity produced into stored energy for later use. You will be in the dark until the weather improves and recharges your system.
2. Off-Grid Systems Have No Net Metering & No Bills
For people who want no utility bills, the off-grid system certainly provides that as you won’t be receiving any bills in the mail after you go off-grid. This also means that any excess electricity that your system produces needs to be stored in your batteries for future use.
The storage requirements will add high cost to the upfront expenses, and to do it properly and have enough storage capacity for your home and a bit extra may take a big bite out of the project budget.
What Happens When The Grid Goes Down
For you, absolutely nothing! You would never even know that the grid has failed, and your life will continue as normal. As a homeowner or business owner, having the lights on when no one else does will make you feel a LOT better about installing the battery bank – every time it happens!
If your system has been properly designed, specified installed, you will have no problems with your power as it will be cleaner, available, and not subject to utility failures ever.
Plus, you are not using any fossil fuels to power your home or business, which adds to that sense of satisfaction knowing that your investment was worth it.
Off-grid or on-grid, the choice remains yours, but the good news is that you don’t need to rush off and spend thousands on storage just yet! Build your system first and see how it runs with the existing utility supply.
If you find that the supply stability starts to become less reliable, you can always add battery banks down the line, but in the meantime, you can sleep that little bit better knowing that you are helping to power your nation too!