What is off-grid solar power system?

Understand everything about isolated grid systems and their applicability

Have you ever thought of a more sustainable way to get energy? One of the alternative and renewable sources that has been growing and gaining more and more space among Brazilians is solar. Brazil is an excellent market for the energy sector, as the average solar radiation that falls on the country's surface is up to 2300 kilowatt-hours per square meter (kWh/m²), according to Cepel's Solarimetric Atlas.

A photovoltaic solar energy system (also called “solar energy system” or even “photovoltaic system”) is a model in which the components of your kit work in order to capture solar energy and convert it into electricity. The energy produced can then be used to supply the electricity grid on a large scale, as happens in solar plants (commercial energy sector), but it can also be generated on smaller, residential scales (solar energy for domestic use). In addition to the solar system for generating electricity, there is also one for thermal energy, which aims to use solar radiation to heat water.

Despite some incentives for the use of photovoltaic energy, which is a type of renewable energy (important as it allows for a reduction in concerns regarding the reservoirs of hydroelectric plants, which in recent years have suffered from lack of rain and excessive sunshine ), some doubts can still be observed among consumers and those interested in applying this system in their homes or in their businesses. How does it work? What is the cost of its installation? Is the financial return beneficial? Where to buy? The questions are many. Some of the answers to these questions can be found in our article on photovoltaic system components, which you can find by clicking here.

To decide how to proceed with the purchase of components for your own energy system, the first thing you should know is that there are two types of photovoltaic systems: those connected to the grid (called on-grid or grid tie) and those that are the focus of this article: those isolated from the network or autonomous (off-grid).

Isolated systems (off-grid)

With higher costs than systems on-grid, isolated systems are characterized by not being connected to the electrical network, that is, the system is self-sustaining through the use of batteries.

For this reason, this system is complete, and includes all the components mentioned in our previous articles, which are divided into three different blocks, which are:

• Generator block: solar panels; cables; support structure.

• Power conditioning block: inverters; charge controllers.

• Storage block: batteries.

The off-grid system is mainly used for specific local purposes, such as pumping water, electrifying fences, light poles, etc.

The energy produced is also stored in batteries, which in turn guarantee the system's operation in periods with little or even no sunlight, such as cloudy days or at night. That is, during the day, at times when energy production exceeds consumption, this excess is sent to the battery bank so that, at night, when consumption is greater than production, this energy can be used to supply the network connected to the system.

As they are not connected to the grid, in an isolated system, more energy cannot be used continuously than that produced by the panels.

Due to the fact that batteries are the only alternative source of energy for moments without sunlight, it is necessary to dimension them taking into account the climatic characteristics of the place and the energy demand on the system. In other words, it is necessary to correctly calculate how much energy will be needed by the residence and take into account the local climate (as it may happen that the location is more conducive to rainy days than sunny days) to determine what the maximum energy storage capacity of the batteries will be. necessary - this ensures that the system will not be interrupted, preventing the site from running out of power.

Off-grid systems can still be small or large. The small ones are those that generate their energy in a smaller scale, but that are still independent of the conventional electric energy, coming from the grid. Some of the advantages of this type of system are:

• Reduction in fossil fuel consumption;

• Increased availability of energy,

• Cost reduction.

These systems, when small, are generally indicated for use in communication antennas, radar monitoring, homes and enterprises in remote locations. In general, they have an energy capacity that varies between 1.5 kilowatt-peak (kWp) and 20 kWp.

Large off-grid systems, on the other hand, are indicated for those customers with high energy demands, and who, like those small customers, are also located in locations with difficult access to the network. These places, in general, receive high levels of solar radiation, but the energy sources most commonly found as responsible for meeting this demand are generators powered by gasoline or diesel. Thus, the advantages of the off-grid system for large projects are:

• Reduction of dependence on fossil fuels;

• Decrease in carbon dioxide emissions;

• Reduction of fuel transportation costs,

• Decrease in the risk of accidents.

Large systems are commonly applied in mining, farms, isolated communities, and companies with factories in remote areas. In general, they have an energy capacity ranging from 1 megawatt-peak (MWp) to 20 MWp.

Some other positive points noted for the system off-grid generally speaking, they are:

• This type of system can be used in more remote locations where it is difficult to obtain electricity. Research and projects are also being developed for the installation of this type of photovoltaic energy in indigenous villages, enabling these communities to have access to electricity.

• Provides power constantly and uninterrupted.

In addition to photovoltaic energy being considered clean as it does not generate waste beyond the plates and does not harm the environment, it is one of the most promising renewable resources in Brazil and in the world, as it causes minimal environmental impacts and reduces the carbon footprint of consumers - will be minimizing their emissions by opting for a way of obtaining energy with low harmful potential.

If you want to know more about how to install your photovoltaic energy system click here.

The return on investment time, in the photovoltaic system, is variable, and depends on the amount of energy that the property demands. Despite this, the advantage of the home system is the economy: once this payback time is reached, the energy bill no longer needs to be paid. Energy from the sun that turns into “free” electricity! You will save a lot of money, and you can put it in savings instead of being spent without bringing much benefit.

Remember to ensure that the components used are certified by the National Institute of Metrology, Quality and Technology (Inmetro), which implemented Ordinance No. 357 in 2014, with the objective of establishing rules for the generation equipment. Photovoltaics.

Unfortunately, there are still few incentives and financing lines for this type of energy in Brazil, which are still difficult to access and have little applicability. It is expected that, with the increase in the consumption of photovoltaic energy systems, new incentives, more applicable and accessible to common housing, will emerge.


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