Grid-tied or off-grid, which is better for a solar energy system? And why?

Many people call us in search of help to get out of the Hydro-Québec network. But when we ask them to explain their motivations to us, we find that what they really want is to abandon the public network and stop paying money to the public service every month. Solar power itself interests them, but what really interests them is the fact that they will be able to make monthly savings and be self-sufficient.

If this you recognize yourself, keep reading because you can accomplish all of these things without necessarily disconnecting your home from the public network. This is called grid-tied solar energy and it is the most common type of solar energy system for any property that has access to power lines.

Why? Because it is much cheaper and requires no sacrifice. A grid-tied system will cost you $ 20,000 to $ 40,000 while an off-grid system will cost you double, or even triple, due to the very high cost of batteries. An grid-tied system allows you to consume as much energy as you want while an off-grid system greatly limits your energy freedom. The question does not even arise, you benefit from staying connected to the public network.

This article answers the following questions:

• What is the difference between a grid-tied solar energy system and an off-grid system?
• What does it mean to be off-the-grid?
• Can we have batteries with a grid-tied solar energy system?

What is the difference between a grid-tied solar energy system and an off-grid solar energy system?

A grid-tied system is a system that is connected to the Hydro-Québec electricity distribution network while an off-the-grid system is a system that is not connected to the Hydro-Québec electricity distribution network. Quebec. An off-grid system is therefore completely independent.

For a grid-tied system, the electricity produced by the solar panels can have two uses; either to be consumed by the occupants of the residence or to be injected into the power grid of Hydro-Québec when it is not in use. The advantage of such a system is in terms of its reliability and the savings it offers, given that Hydro-Québec can always supply electricity in the event of an energy deficit and that compensation is offered when electricity is sent back to the network. In addition, a grid-tied system is less expensive than an off-grid system since it does not require the installation of batteries and charge regulators.

For an off-grid system, the electricity produced by the solar panels is directly stored in batteries for immediate or later use. The amount of electricity accessible in an off-grid system therefore depends on the performance of the solar panels installed as well as the number of batteries installed, which is not the case for a network connected system. An off-grid system is therefore more expensive since it uses batteries to store the energy generated by solar panels. Since an off-grid solar energy system has no access to the public power grid, batteries are mandatory.

In general, off-grid systems are more frequently found in rural or remote regions (where it is impossible or very expensive to be connected to the main electricity distribution network) while grid-tied systems are more often located in urban areas.

What does it mean to be off-the-grid?

Living off-grid comes with energy sacrifices. The sacrifices are in relation to the number of devices that can be used at the same time as well as the number of devices that can be used in one day.

The number of devices that can be used at the same time refers to the concept of power (or power demand), which corresponds to the intensity of the battery discharge current induced by the use of a given electrical appliance. The problem is that the capacity of a battery exponentially decreases the more the intensity of the discharge current increases, the latter increasing the higher the power of an electrical appliance. Thus, the capacity of a battery is closely linked to the power of the devices it powers.

This means that if you do not want to drain the energy in your batteries too quickly, you have to be careful with the power of the devices that you decide to operate at the same time. The power of a device is measured in watts and is often indicated on the device’s data sheet. A 1000 watt power appliance is considered to have high power.

The number of devices that can be used in a single day refers to the concept of energy. The more devices you use simultaneously, the more energy it will take to operate them. In the same logic as before, if you do not want to drain the energy contained in your batteries too quickly, you have to be careful about the amount of devices you will use in the same day.

Therefore, living off-grid forces you to do monitoring to make sure that the amount of energy produced by your solar panels is less than or equal to the amount of energy you consume. For all these reasons, we always recommend staying connected to the public network.

Can we have batteries with a grid-tied solar energy system?

It is important to mention that grid-tied solar energy systems are notable to provide you with electricity during a power outage because it is a necessary condition established by Hydro-Québec. to prevent electricity auto producers from sending electricity to the grid and endangering repair technicians.

You may be wondering if it is possible to be connected to the network while having batteries. The answer is yes. For this, there is a third type of system, a solar energy system with backup batteries (also known as a hybrid solar energy system).

These systems connect and store energy in the network, but also include batteries. When your energy consumption is lower than the energy produced by your solar panels, the energy excess is sent to the batteries until they are fully charged. When your energy consumption is lower than the energy production of your solar panels and your batteries are full, the energy excess is sent to the public network and you receive energy credits according to the amount of energy that you send to the public network. The functionning of a hybrid solar energy system is therefore very similar to a network connected system, the only difference being that it also has batteries.

That said, there are two main reasons why you would want to add batteries to a plugged-in solar power system:

• To have emergency power in the event of a breakdown
• To store energy to resell it later when the price is higher (especially during peak hours)

However, the same warnings apply: the batteries remain unaffordable and adding them to your network connection system significantly increases your return on investment.

Hybrid solar power systems provide additional peace of mind and help you get the most out of the electricity you generate but are more expensive than a conventional grid-tied system. It is up to you to decide if the extra cost is worth it.

Conclusion

To conclude, in the current economic and energy context, energy autonomy using batteries is still very inaccessible for most of the population. Being very expensive and having a short lifespan, the acquisition of batteries is not recommended for those who experience infrequent and short power outages. However, in the case of off-grid installations, the acquisition of batteries remains essential. Keep in mind that you will not be able to have the same lifestyle as when you are connected to the Hydro-Québec network.

Please do not hesitate to contact us for more information, we will be happy to assist you. Our affordable, reliable and turnkey solar energy systems will fully satisfy you. Give us the chance to impress you and share our solar expertise with you.