The Photovoltaic System
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How does photovoltaic energy work?
The sun’s rays shine on the photovoltaic panels which are placed at a location where there is considerable exposure to the sun, generally on rooftops. On contact with the panels, the sun’s energy is transformed into an electrical current which will be used by the electrical equipment where the system is installed. However, the generated current is a Continuous Current (CC), which is different from the current which comes from the plug, the Alternate Current (AC). For this reason, the electrical current has to be processed through equipment known as an Inverter which will transform Continuous to Alternate Current. On leaving the Inverter, the system is connected to a Switchbox at the site, thus being integrated into the electricity network and ready to supply power to the electrical devices which are switched on. -
What are the components of a photovoltaic system?
The two components of a Photovoltaic System are the Photovoltaic Panels (also called Modules), which will capture the sun’s energy and transform it into Continuous Current, and the Inverter, which will transform the Continuous Current into Alternate Current, thus making it ready for use at the site of the installation. There is also other equipment such as cables, electrical devices and fixation structures. However, these represent just a small part of the system. -
What is the difference between a photovoltaic system and a solar heater?
They are two totally different things! The solar heater is used exclusively to heat household water and the entire plumbing system at the installation’s location has to be modified for the system to work. The Photovoltaic system on the other hand is used to generate electrical power and for this purpose can be used to run all household electrical equipment and devices at the location. In most cases any major structural modification to the electricity network is unnecessary. They are two totally different things! The solar heater is used exclusively to heat household water and the entire plumbing system at the installation’s location has to be modified for the system to work. The Photovoltaic system on the other hand is used to generate electrical power and for this purpose can be used to run all household electrical equipment and devices at the location. In most cases any major structural modification to the electricity network is unnecessary. -
What is the useful life of this equipment?
Usually, the guarantee is that the panels will be operating at 80% of their nominal capacity by the end of 25 years. Hence, the system will not cease to operate but rather generate less energy. This takes place because the system is made up of materials known as semi-conductors which result in the generation of electricity from the photovoltaic panels undergoing an initial loss of efficiency on being exposed to the sun and by about a further 0.50% loss with each successive year of operation. In the case of the Inverters, replacement is recommended after 15 years of operation due to the natural wear and tear of any electrical equipment. It is worth remembering that there are reports of panels installed more than 40 years ago and still operating today. -
Does the equipment occupy much space?
This will depend on the generation capacity of the system. The more energy that is required, the larger the system. For example, a system sufficient for the consumption of a family of four will occupy a space of about 25 m² for the modules while the inverter can easily be installed vertically on a suitable wall, preferably close to the switch board at the location. -
What is the equipment guarantee?
Most module manufacturers offer a ten year guarantee for the physical integrity of the equipment and 25 years for system performance, guaranteeing also that it will be operating at 80% of its initial capacity in the 25th year of operation. On the other hand, the inverter guarantee may vary between five and ten years depending on the manufacturer. -
Does the equipment need much maintenance and operation?
A photovoltaic system operates automatically and consequently no manual operation is required for it to function. All that is needed is to install it. On the question of maintenance, the photovoltaic panels are extremely resistant and durable and for this reason dispense any kind of maintenance. Any cleaning that is necessary occurs automatically due to the equipment’s exposure to rainwater itself which removes the impurities that might reduce the system’s performance. -
Is the equipment imported or manufactured in Brazil?
Most of the equipment is imported with technology originating from a wide range of countries: Germany, Canada, Japan, United States, among others. However, in view of the enormous potential in Brazil for solar energy, the leading manufacturers are already beginning to build plants in Brazil and initiating the indigenous manufacture of the equipment.
Using the sun’s energy
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How can I buy a photovoltaic system?
At ENGIE, the system is very simple. On requesting an estimate, your system’s dimensions are established based on the energy consumption you wish to reduce. Hence, the first stage is to have your electricity bill to hand as well as an idea of where the installation is to be sited. We can then establish the dimensions of the system and evaluate if there is available space, thereafter generating a Preliminary Proposal which will include the basic aspects of the project. This will help you to better understand our solution. Should there be an interest in taking the matter further, our engineering team will prepare a detailed project, employing specific software so that you get the ideal system customized for your residence or commercial activities. The project is presented as a Complete Proposal together with an economic feasibility analysis as well as the environmental benefits accruing from your system.
The benefits
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How much can I save using a photovoltaic system?
As long as there is enough space to install it, a residential system represents savings of approximately 90% of the current electricity bill but not 100% since a minimum cost is still due to your power Distributor. The savings in just the first year of operation of one of these residential systems is of the order of R$5,000.00. This saving can be greater or smaller depending on where the equipment is installed. -
How long does it take for the system to pay for itself?
The value which shows how long the system will take to pay for itself is called the payback. The calculation of payback is influenced by the size of the system, by the solar irradiance available at the location and by the forecasted cost of electric power during the useful life of the system. The bigger the system, the better the financial performance will be by virtue of economies of scale. Household systems generally enjoy a payback of between 5 to 8 years while this can be less for low voltage commercial systems. -
Might I be able to eliminate my electricity bill totally using a photovoltaic system?
Might I be able to eliminate my electricity bill totally using a photovoltaic system? Unfortunately, you cannot eliminate your electricity bill altogether in Brazil. If the consumer unit where the system is installed is in the B tariff group, the case with residential consumers, you will have to pay the Availability Cost, which in turn will depend on the type of electrical connection in your home. In the case of residential consumers, the amount is charged as follows: Single phase network: amount in local currency equivalent to 30 kWh. Two phase network: amount in local currency equivalent to 50 kWh. Three phase network: amount in local currency equivalent to 100 kWh. Thus, a system able to supply 100% of power consumption is not recommended. The indication is that the system’s dimensions be calibrated to supply the average residential consumption discounting the minimum consumption related to the Availability Cost. For example if a three phase installation consumes an average 600 kWh/month, the system should be dimensioned to produce 500 kWh/month, the average consumption (600 kWh/month) less the minimum consumption for three phase residences (100 kWh/month). Finally, tariff A group clients must continue paying Contracted Demand and representing the use of the concessionaire’s wire connection. -
What happens if I generate power and do not consume at the time?
You will generate power credits. These can be used in periods when the system is not generating energy such as at night or on rainy days. This is possible since Brazil has adopted the Power Compensation System, known internationally as net-metering. For instance, if you are not consuming the power generated by the solar energy system during the day because you are not at home, this power can be injected into the electricity distribution network and will supply the nearest consumption point to where the energy was generated, so producing credits for you. These credits can be used for example at night when you arrive home and use electrical household utensils, and this without having to take any particular initiative in this respect. -
If there is a power outage, am I going to continue generating power?
As the system is connected to the distribution network, the system is not going to continue generating energy if there is a power outage. This is due to safety reasons. It is essential that the network not be energized in the event that maintenance is required. -
Can I use batteries as backup?
The use of batteries is possible should the owner of the system deem it of interest whether for connected or isolated systems, and which are not connected to the Distributor’s network. However, batteries are not recommended due to their high price, which significantly alters the overall cost of investment in the system. Batteries also have a notably reduced useful life and require frequent maintenance. -
Can I sell the power which I generate and do not use?
No, excess energy generated by a photovoltaic system can only be injected into the network to become a credit, not being available for sale by the generator. However, credits generated by a photovoltaic system can be allocated to other consumer units in accordance with Aneel’s Normative Resolution 482/2012. -
I live in an apartment but I have a house as well. Can I use my house to generate power for my apartment?
Yes, in Brazil you can generate power in one place and the excess generated in that locality can be discounted against the cost at other locations as in the case above as long as the registered consumer is one and the same. So should there be no space in a given location, you can install the system at another location using the power generated to be discounted from total consumption. -
I live in a residential condominium and we want to install a system for generating power for the members of the condominium. Can it be done?
Yes, it is possible to install the equipment in a given location in the condominium and prorate the energy among condo residents. This kind of installation is called “installation for projects with multiple consumer units”, at the same time, also contributing to the lighting of common areas and reducing the cost of power to the condominium. -
I have a company and other acquaintances also have companies. We want to buy a system for generating power for all of us although we are not all in the same place. Is this possible?
Yes, it can be done. For this purpose, all the companies have to be supplied by the same power Distributor and set up a consortium or cooperative. In this way, its participants can benefit from the power generated by the photovoltaic system, even when distant from the point of generation, distributing it among the various consumer units.
Installation of the system
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Can the system be installed anywhere?
Usually it is installed on a rooftop, there being no restrictions in relation to type (ceramic tiles, fiber cement or concrete). The optimum rule is for the system to be directed to the north with an inclination equal to the local latitude. Small variations in the siting of the system do not cause any major loss of production efficiency. -
How is the installation conducted?
Our installation team goes to the installation site and respecting all safety procedures and norms, executes the installation in an agile and efficient way. Depending on the kind of rooftop where the installation is to be made, there may or may not be a need for drilling to secure the positioning of the metallic structures where the modules are to be placed. The system’s electrical connection uses the network which already exists at the site and for this reason, on most occasions there is no need for any alteration in the electrical installations. -
Does the installation process take very long to be completed?
In the case of a residential system, an installation will take from 2 to 3 days to be concluded. On the other hand, for the larger systems, installation time varies considerably in accordance with the site and the number of installation personnel. -
Is any type of civil or reinforcement work required?
Normally, there is no need for alterations to the civil construction of the house given that the load capacity of the rooftops is suitable for installing the panels and the existing electrical system itself is used for connecting the photovoltaic system. -
Can I install a photovoltaic system myself?
Only professionals registered with the Regional Council for Architecture and Agronomy (CREA) can sign off on an electrical project needed for the local power distributor’s Access Opinion. An engineer or electro-technician must therefore be hired to prepare and register the project. ENGIE Solar has a proven track record as well as engineers specialized in solar power. These professionals work in accordance with all the safety norms and those established by the energy concessionaires, offering a complete solution to the clients. -
Am I going to be required to make specific requests to the distributor?
No, ENGIE executes the entire installation process and the commissioning of the photovoltaic system. So the client is not involved in any bureaucratic procedures with the energy distributor. We are responsible for realizing all stages of the installation from the preliminary project to post installation technical assistance and monitoring, merely requesting the client for the documents needed for these requirements. -
If I install a system in my home and then move, can I transfer the system to another residence?
There are no regulatory barriers for such a transfer although such a move is not economically recommendable. The rationale in the market is the same as other systems such as solar heating or gas: once installed, the investment is incorporated in the value of the property given the added value of the product. -
How am I going to know how much power has been generated?
ENGIE offers access to the photovoltaic system’s monitoring software. Developed by the inverter manufacturers, with this software the user can check the system’s performance in real time as well as being able to access various statistics which the software provides. Thus, you can check how much power the system is generating at any moment in time.