20 abril, 2019 Off By admin

Recently you have heard a lot about “self-consumption”. If you are wondering what it is or have doubts about its operation, we explain everything related to this term so fashionable lately.


We are going to analyze if self-consumption really suits, if all the investment made in the photovoltaic system will be amortized in a few years or if it is not convenient.

What is self-consumption?


The “self-consumption” is to produce or manage what we consume , be it food, energy, water or even clothing! This practice can be carried out by individuals, families and even companies or public centers.

At we are going to talk about self-consumption as the production of the energy that you consume.

Energy self-consumption systems can be isolated or connected to the grid .

The isolated system is used to produce energy that we consume at the moment or store in batteries for later use, while the grid connection system allows us to pour energy into the electricity grid to discount this from the electricity consumption of our bill, that is known as “net balance” (or net metering), which we will explain later.

Advantages of self-consumption

Among the advantages of self-consumption are the following.

  • With the cheapening of self-consumption systems and the increase in electricity rates , it may be cheaper to produce our own energy. And once we recover the investment, we have free energy for life!
  • Self-consumption systems use free, inexhaustible, clean and environmentally friendly sources of energy , such as solar or wind energy.
  • Energy losses are avoided by transporting it through the electrical network.
  • The energy dependence of our country with the exterior is reduced .
  •  Problems are avoided to supply all the demand in peak hours, known for power cuts and power surges .

Analysis of possible disadvantages

One of the main obstacles to self-consumption is the cost of purchasing the systems . This is no longer a problem since prices are becoming cheaper , while the prices of electricity provided by electric companies expect continuous increases.

Another obstacle to self-consumption is that the generation of electricity is intermittent and depends on the weather conditions. So, if we have a solar panel system, electricity will not be generated at night, and unless we have a storage system, we will not be able to have electricity at night.

But, this will no longer be an obstacle, since it will proceed to regulate the so-called “net metering” or net balance , which is that it can pour into the electricity grid the excess consumption produced by our self-consumption system .

In this way, the electricity company that provides us with electricity when our system can not generate it, will discount us from our monthly consumption , which we have discharged.

For example, if we spend 200 kWh per month, consuming 100 kWh of our solar panel system and 100 kWh of the network, and also, our solar panels discharge 80 kWh to the grid (in total they produce 180 kWh), the company will charge us only 20 kWh difference.

Also,  if we go on vacation, all the electricity that our system produces while we are not, we can spend it throughout the year.

The CNE (National Energy Commission) already has a draft of the royal decree to regulate the process of self-consumption and in theory should be ready in March or April 2012.  It is expected that the parity will be reached in 2012 and 2013 large photovoltaic installations and in 2016 for homes.

Likewise, we remind you that in the technical building code, minimum production of DHW (sanitary hot water) is already established through thermal solar panels, in newly constructed buildings and those that are considerably reformed

What is photovoltaic self-consumption?

Auto Solar Consumption – Principle of operation 

The operation of photovoltaic self-consumption installations from solar energy, could be summarized as: “a system for generating electric power from solar energy for energy savings” .

To develop more in detail the operation of this type of facilities, we have written for you this article that aims to give the basic information of power generation for self-consumption and savings with the use of photovoltaic panels.

We also want to remind you that, if you are a professional and you need a self-consumption equipment supplier , we have some models of  solar kit for self-consumption both for homes and for industry. These are some examples that might interest you:

  • The most basic would be the Solar Kit 1500W
  • For slightly larger houses the 2000W Photovoltaic Kit
  • For a medium / large housing the 5,000W solar panels kit
  • For a large house, the self-consumption 10,000W solar kit

All the kits we supply are composed of high-end equipment , no Asian equipment that always end up having incidences of various kinds. And it is fundamental for us that the professionals who work with us have a high quality profile why, at the end of the day, it is the people (one family, one entrepreneur …) who will receive that kit and it should work and have an always optimal performance for at least 30 years. And that is only achieved with quality photovoltaic products.

In any case, if you need to configure a self-consumption kit for your project or simply ask us for prices of our solar-panel kits, get in touch with our technical-commercial department without any commitment.

What is photovoltaic self-consumption connected to the grid?

As described in point 2, basically a self-consumption installation connected to the grid consists of solar panels, wiring, a photovoltaic inverter and a zero injection device (optional).

The solar panels are responsible for generating electrical energy from the solar radiation that falls on them, the inverter convert that electrical energy from continuous to alternate to make it suitable for the consumption of electrical equipment and the wiring, logically, connects the photovoltaic equipment.

The zero injection device , for surplus solar energy, is optional, and its purpose is to avoid pouring energy into the electrical network.

What is a kit of solar panels for solar consumption?

First we must distinguish two types of photovoltaic installation for self-consumption :

  • A) Installations connected to the electricity network
  • B) Isolated installations of the electrical network (use of batteries)

In our case,  we will only talk about type A , because type B is a type of battery system that is not the subject of this article. The principle of operation of a selfconsumption photovoltaic installation connected to the network consists of the placement, on our roof or other available surface, of solar panels.

These solar panels will be connected in turn to a photovoltaic inverter that converts the direct current , generated by the plates, into alternating current, which is what is needed to feed the usual electrical equipment (appliances, motors, …). It is necessary that there is always an electric network.

That is, in broad strokes, and in a summarized way that it consists in solar photovoltaic kit for solar self-consumption .





Typical scheme of a photovoltaic self-consumption installation in a dwelling

Where is the energy self-consumption system connected to be able to use it?

Fundamentally, and without entering into electrical specifications that would be the work of an electrical installer, the inverter output would be connected to the ICP input of our home and depending on the energy demand of our house, the energy of the photovoltaic installation will be taken. and the network, in this order.

That is, because the installation of self – consumption of energy is the electrical generation system closest to our consumption, our house will always first take energy from that nearest source, and if it needs more it will take it from the grid, this will never mean power cuts, that is, the two generations go in parallel. It is a fundamental principle of electricity.

What is photovoltaic self-consumption and why is it convenient?

Before analyzing the advantages of self-consumption, we briefly describe the two main ways of using the energy produced by photovoltaic energy: in situ exchange and, as mentioned, self-consumption.

With the exchange on site, the energy produced by the solar panels is partly introduced into the electricity grid. This re-entry is done through a system called “valorization”. 

The economic advantage is that of obtaining compensation in exchange. This is not a real sale, but it is more correct to define it as an economic compensation. 

In fact, with the emission to the grid of the energy obtained from a photovoltaic system, a form of reimbursement is obtained in the invoices equal to the quantity of energy sold, precisely an economic compensation given by the relation between the energy extracted from the network and the energy sold.

What is the production of self-consumption?

The process and functionality of a photovoltaic self – consumption system is completely different. In this case, as the word suggests, all the energy produced by the solar system is only used for self-consumption of energy in the home or industry in which the plant operates. Nothing is put back on the network. 

But what happens if the plant produces more energy than it consumes? The latter should be irretrievably lost. 
To overcome this problem, a photovoltaic system dedicated to self-consumption provides for the possibility of accumulation

Through the use of inverters or batteries, surplus energy can be used when production is low (bad weather, night, etc.).

The two main types of storage, as mentioned, are the inverter and the  external battery . In the first case, the lithium battery is placed in the same inverter, occupying very little space; If the solution of the external battery is used, it is necessary to provide a special space to contain them, since it is more bulky. 

The necessary spaces are separated, both solutions require that, if the energy accumulated in the batteries is no longer sufficient to meet the energy needs of the home, the system is removed from the grid and, if not, when the batteries have already reached their level. limit. maximum level, all surplus energy is fed into the operator’s circuit and then sold.

There is also a third type of system completely disconnected from the network for those who wish to be completely independent (with the pros and cons that follow), or for those who are obliged because the Network can not access them and live in specially isolated environments . In this case we talk about off-grid systems .

But let’s go back to the main topic and ask ourselves the question: Which of the systems described so far is the most convenient? 
A photovoltaic system in self-consumption with the possibility of accumulation is the most profitable formula. 

Basically, this is due to two reasons: 
• the energy taken from the grid has a higher cost than the energy introduced: this means that each kilowatt purchased will be paid at a higher price than that obtained by selling it to the manager. 
• Being able to free themselves from the purchase of electricity online, will be completely self-sufficient (except for the fixed costs due to the manager).

For this system to be profitable, it is necessary to provide a good storage system, such as those described in the previous paragraphs, to avoid unpleasant surprises during periods of lower productivity of the photovoltaic system.

What happens if I generate more energy than I use? Do I have compensation for this?


Electricity (green) is generated with solar panels. You can use part of this power directly, for example, for computers and lighting in your home. 

It will return the self-generated electricity that it does not use directly to the normal electrical network to which it will always remain connected. Energy providers are required by law to fully compensate for the electricity they return with the electricity they are supplied with, including the energy (and VAT) tax of up to 5000 kWh. 

This is called balance. This is an advantage because the electricity purchased is more expensive (on average 23 cents / kWh) than the power rate (from 7 to 9 cents / kWh). Therefore, you save on your full purchase rate.

If you produce more electricity in equilibrium than you buy from your energy company, you will have a negative net consumption. Receive a reasonable fee for electricity that returns above your consumption. You will not receive an energy tax in this case. 

Reasonable power compensation is low and varies according to the energy company, from 70% of the price of basic electricity (around € 0.05) to € 0.09 per kWh. That is not financially interesting. It is better to choose your solar energy system so big that you do not generate more than your average consumption.