Photovoltaic system self-consumption: meaning and useful information

In Italy in 2023, photovoltaic plants with 5,234 MW of new capacity and approximately 488 MW of new wind power came into operation. This is a confirmation of the positive trend of renewables, certainly the result of a cultural change but also of significant technological upgrades and economic advantages in the photovoltaic sector. This offers an increasingly wide opportunity both for families and for companies, which, from the traditional approach of consumers subject to market fluctuations, can finally evolve into prosumers, i.e., producer-consumers of energy. You have certainly heard about optimizing self-consumption with reference to photovoltaic systems, but what does it actually mean? Let’s imagine a factory with an attached photovoltaic system installed on its roof. Well, self-consumption in this case consists of the possibility of consuming on-site – reconciling production timing vs. consumption timing – the electrical energy produced by the photovoltaic system to meet the energy needs of the company. Producing and consuming the electrical energy produced by a photovoltaic system simultaneously means actively contributing to the energy transition and sustainable development of the country, promoting energy efficiency, and promoting the development of renewable sources.

What is meant by photovoltaic self-consumption

Photovoltaic self-consumption refers, therefore, to the possibility of using the electrical energy produced by our system in the most contextual way possible to the production of energy itself (or belatedly by storing it in storage systems), thus reconciling energy demand with energy production and limiting, in part or in whole, the need for input and withdrawal from the external electricity grid. This process involves the direct supply of electrical devices, appliances, and internal systems using the electricity produced in real time. This means that during daylight hours, the generated energy is primarily consumed locally, thus reducing dependence on the traditional electricity grid and maximizing the efficiency of the photovoltaic system. This approach not only helps reduce energy costs but also serves to maximize production from photovoltaics.

How photovoltaic self-consumption is measured and analyzed

Monitoring the self-consumption of the photovoltaic system is crucial to maximize energy efficiency and take full advantage of the photovoltaic energy generated. Knowing the amount of energy produced and consumed internally allows for the evaluation of the system’s effectiveness and identification of possible areas for improvement, often related to our own consumption habits. A monitoring process that provides detailed information on consumption habits, allowing users to make informed decisions to maximize self-consumption and reduce dependence on the traditional electricity grid. Furthermore, constant monitoring allows to detect any anomalies or faults in the system in real time, ensuring timely intervention to maintain optimal performance. Monitoring self-consumption thus not only contributes to a more efficient use of solar energy but also ensures intelligent and reliable management of the photovoltaic system.

The different types of meters

In a photovoltaic system, there are two meters, namely the production meter and the exchange meter, which perform distinct but complementary roles. Here is an overview of the differences between the two and how they work.

  • Production meter The production meter, also known as the energy produced meter, records the electrical energy generated by the photovoltaic system. Each time sunlight is converted into electricity through the combined operation of the photovoltaic modules and the inverter, the production meter records the amount of energy produced, usually measured in kilowatt-hours (kWh). This type of meter provides crucial information on the efficiency of the photovoltaic system and the amount of solar energy converted into usable electricity.
  • Exchange meter The exchange meter, also known as the bidirectional or balancing meter, records both the electricity that is fed into the grid (when there is excess energy compared to self-consumption) and the electricity taken from the grid when the system is not in production conditions or cannot meet the household’s demand, for example at night or on days with low insolation. During peak solar production hours, if the system generates more energy than is consumed locally (in the absence of a storage system), the excess energy is sent to the electricity grid and recorded as “energy credit” through the exchange meter. Conversely, when solar production is insufficient to meet the energy demand, the necessary energy is drawn from the grid and recorded as “energy debit”.

The operation of the production and exchange meters is regulated by specific regulations and varies depending on the tariff system.

Photovoltaic self-consumption: how to calculate it

In summary, while the production meter records the energy generated by the photovoltaic system, the exchange meter manages the balance of energy produced and consumed.

Total energy produced – energy fed into the grid = self-consumed energy Example: if over the course of a year the first meter recorded 5,000 kWh produced by your system and the second meter recorded a total of 2,500 kWh of energy fed into the grid, subtracting the energy fed into the grid from the total energy produced will give you the self-consumed energy, which in this case would be 2,500 kWh. If you are looking for a company experienced in the installation and also in the verification and management of the energy produced by your photovoltaic system, rely on Southenergy, a company from Puglia with 16 years of experience in the renewable energy sector. Southenergy’s areas of activity range from the design and construction of turnkey photovoltaic systems to the enhancement of existing plants through repowering and revamping activities, preserving projects 360° through crucial activities such as O&M (operation and maintenance), due diligence, asset management, monitoring, and digital energy. ‍ Since 2008, Southenergy has been operating to guarantee your investment, monitoring and verifying with extreme care that the operation and performance of your plants are always optimal. All this through a corporate organization that benefits from highly qualified internal personnel and equipment and means of ownership to be able to manage the entire value chain promptly in the construction and management of energy. Discover the efficiency of our photovoltaic systems and the turnkey solutions we have reserved for those who have already chosen us: visit the section of our website dedicated to some of the projects we have carried out. If you would like more information or a free technical consultation, contact us by filling out the form below. One of our experts will analyze your request, identifying the solution to your energy problem.

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