Off grid and on grid: what are the different systems and which one to choose for yourself

People interested in investing in renewable energy sources will certainly meet the terms off grid and on grid . These two variants of systems will apply to modern and highly reliable photovoltaic installations, which are becoming more and more popular among investors. But what is the difference between the on grid system and the off grid system? The answers to the most frequently asked questions are presented in the following entry. We invite you to read!

Off grid – island system

An off grid photovoltaic installation is an installation that is  not connected to the electricity grid . Its distinguishing feature is that it is itself an independent energy system. In the industry, this option is known as the so-called the island system (however, this is a colloquial expression). Practice and industry experience show, however, that most often off-grid photovoltaics do not generate enough power to ensure full energy self-sufficiency in the household.

In what situations, however, this type of installation will work best? It will be especially useful when there is a need to connect electricity to some not too large, isolated object, such as a summer house or a plot of land. At such moments, using the functionality of the island system may turn out to be a real hit.

Off grid system – when is it worth installing?

An off grid photovoltaic installation will not always work. However, there are also places where its installation will be perfect. Here we are talking, among others o PV installations in an area at risk of frequent power cuts. The network in such places can be quite unpredictable, which is why investors often decide to create conditions conducive to the production and distribution of electricity in one. In such a case, the off-grid installation will not only consist of an energy generator and an inverter, but also an additional, extremely important element. I am talking about  an energy store .

Off grid solar farm – more expensive

By calculating the cost of installing a PV installation, you can see that  choosing an off grid system is much more expensive than choosing a grid connected photovoltaic system . It should be noted that for the proper operation of an off grid photovoltaic installation, energy storage is necessary . This works best with the use of specially installed energy accumulators, known as energy storage.

Moreover, when designing an off-grid system, one should also take into account e.g. total power of devices connected to a given photovoltaic system. This includes the amount of time the devices operate when using energy derived only from batteries. Based on these data, not only the number and capacity of energy storage will be selected, but also the technology used in them and the power of the inverter.

It is worth emphasizing, however, that their purchase is quite expensive – the price for energy independence in such a case becomes considerable. To this should be added the need to replace the batteries. These wear out after an average of 10,000 charging cycles. This means that investors must take into account the necessity to incur additional financial outlays every 5 – 8 years. The costs of off-grid installation are therefore not small.

Advantages of off-grid photovoltaics

Although off grid systems in photovoltaics in Poland are not very popular, they generate access to several benefits that are worth mentioning.

• They allow us to become independent from electricity suppliers, but not only.
• The big advantage is certainly the possibility to use the full accumulated electricity, and not, as in the case of the on grid system, only 70-80% of the produced surplus.
• Off grid photovoltaics will be perfect especially in places where there are frequent grid failures or it is quite difficult to supply electricity from the grid.

System on grid – what is worth knowing about it?

The distinguishing feature of the on grid photovoltaic installation is its connection to a standard power grid. This system consists not only of an inverter, whose main task is to convert direct current into alternating current with a voltage of about 230 V, but also cabling and protection, most often in the form of bidirectional meters .

It is thanks to their indications that it is possible to measure the exact amount of not only generated electricity, but also that sent back to the grid and taken from it. Investors who decide to install on grid have full control over energy production in the prosumer installation. No wonder then that such systems are in practice much more often used than off grid systems.

On grid installation and an attractive discount system

What benefits can investors who decide to purchase and install a photovoltaic on grid system can count on? First of all, they will gain access to the  option of using the so-called discount system . Its essence is that the surplus energy sent to the grid can be successfully collected at a later date. Most often, the excess of produced energy is used in the period of reduced photovoltaic efficiency – e.g. at night or in winter.

However, storing energy from on-grid installations is not entirely free. Prosumers who are owners and users of installations with a capacity of up to 10 kW can collect 80% of the surplus energy. Those who use installations with a capacity of more than 10 kW to 50 kW can count on the possibility of receiving 70% of the surplus of energy produced.

The billing in question is based on the so-called net metering. It is also worth emphasizing that, under the Act, prosumers are guaranteed to store the generated surplus energy in the power plant only for 365 days from the date of their transmission. During this time, they should pick them up – otherwise they will simply be lost, and the prosumers will eventually lose.

System on grid – when is it worth choosing?

Photovoltaics on grid is most often chosen when investors think about PV installations in houses connected to the power grid. Compared to the off grid system, the on grid structure is much easier to build, and the electricity produced can be used on an ongoing basis. In addition, it is worth emphasizing that on grid photovoltaics is a solution available from most suppliers, so it is a widely tested and common option. Additionally, it is an affordable investment with relatively low investment costs – especially in combination with the costly installation of an off grid system.

Off grid or on grid – what to choose?

Investors considering the choice of the type of PV installations should know that the  on grid installation is by far the most frequently chosen and widely recommended in the industry . This type of photovoltaics can be found in the wide range of our services.

• The number of satisfied investors is constantly growing, and the  reliability of on-grid installations is really appreciated by many!
• It is worth emphasizing that the most important benefits associated with the choice of this option include its attractive costs and the possibility of selling surplus electricity to the grid.
• In comparison with the off grid installation, the on grid system is chosen much more often in Poland and this solution is dedicated to investors who want not to overpay, but still use reliable and environmentally safe photovoltaics.
• Moreover, PV on grid installation is considered to be the  most profitable in terms of all its aspects.
• In addition, it is also worth pointing out that the on grid system is as secure as possible . In the event of any failure, the installation is automatically cut off, which allows you to effectively protect yourself from possible electric shock.