Below the Header Ad

What happens to excess energy from solar panels?

The owners of photovoltaic solar installations can benefit from discounts  on their  electricity bill by feeding the surplus energy produced by their solar panels into the electricity grid. This means that if you produce more energy than you spend, you can sell it to your energy retailer, which will deduct the corresponding amount from your electricity bill.

What can you do with the surplus energy from your self-consumption installation?

The approval of Royal Decree Law 244/2019 in April 2019 represented a great advance for those who have bet or want to bet on photovoltaic self-consumption. The Government not only managed to reduce the uncertainty of consumers, but was also clearly committed to reducing pollution and  favoring savings  by citizens, communities and companies that opt ​​for energy self-consumption.

Among the changes brought about by this regulation, we find the redefinition of the term “self-consumption”, which is now understood as “the consumption by one or several consumers of electrical energy from generation facilities close to those of consumption and associated with the same”.

What happens to excess energy from solar panels?

Two types of self-consumers are also defined: individual ones, who can take advantage of any form of self-consumption (whether individuals or companies) and collective ones, when several people or companies share the same source of self-consumption energy (from neighborhood communities to industrial estates). industrial).

Article inline ad #1

Another novelty is the simplification of the administrative and technical procedures necessary for the registration of facilities, eliminating some processes that hindered them. In addition, administrative obstacles are eliminated for some of the categories of self-consumption installations.

What is surplus disposal?

 The amount of energy that your photovoltaic installation produces and that you do not spend is called  energy surplus . This surplus can simply be lost without being used, you can store it in batteries for future use or you can dump it into the conventional electricity network, that is, let it leave your house to be used by others.

When you pour it into the electricity grid, it becomes the property of the supply  company  with which you have your electricity contract, so you can negotiate a price with them so that they return the energy that you contribute to them as a discount.

However, this has a downside, which is that  you have a limit  up to which that discount reaches. You can only discount the maximum of the variable part of your electricity bill. That is to say, in your bill there is a fixed part (around 30%) that you pay just for being connected, and a variable part (70% approx.) which is what you will stop paying by consuming your own solar energy and from where You will obtain the discount for the discharge of surpluses in case of not using the total of the energy that you produce.

How does surplus compensation benefit the consumer?

In order to understand how we can benefit, we must know that there are different modalities that we can take advantage of. RD244/2019 establishes two modes of self-consumption: without surpluses and with surpluses.

  • Self-consumption without surplus: as its name suggests, this type of facility has a system that does not allow any discharge to the grid, either because it is isolated (without connection to the Electricity Grid) or because it does not want to discharge its surplus. It has the advantage that its administrative processing is very simple.


  • Self-consumption with discharge of surplus: for installations that are going to discharge energy into the network, there are two modalities:


Acceptance of compensation (simplified):  small renewable consumers of up to 100 kW can compensate in their bill, month by month, the energy consumed through the network with the surplus energy that they have not consumed at the time and have discharged into the network .

Not eligible for compensation:  includes those installations greater than 100 Kw, whose surpluses will be dumped into the network but under a sales regime, not compensation. The same rules will apply to it as to any electric power production plant.

There is a third subsection in the form of self-consumption without surpluses, but covered by compensation, which is exclusive to shared self-consumption. The installation of solar panels will be equipped with an anti-dumping system but, even so, consumers can take advantage of the simplified surplus compensation mechanism.

In this case, the subject of liquidation of the surplus energy will be the marketer of each associated consumer. Otherwise, the ownership and responsibility for the installation are joint and several.

Self-consumption without surpluses vs. self-consumption with surpluses.

The biggest change for users is the differentiation of two forms of self-consumption: self-consumption without surpluses and self-consumption with surpluses.

Self-consumption without surpluses:

No discharge is made to the electricity grid even if more energy is generated than necessary in the installation of photovoltaic panels. Normally they are users who want to  completely disassociate themselves  from marketers or homes where the electricity network does not reach. To compensate, users can install smart batteries so as not to waste the energy generated and not consumed.

In addition, with the modification in the regulations, these facilities are exempt from the need to obtain access and connection permits for the power generation facilities.

The problem with this model is that you are exposed to an episode of  energy shortage . If at any time your installation fails or you consume more than you generate, you do not have the support of the electrical network to supply you with extra energy.

Self-consumption with surpluses:

By remaining  connected to the electricity grid , they can discharge into the electricity grid when they have excess energy from what they have generated, but with conditions. It is divided into two subgroups:

Type A:  these installations are eligible for surplus compensation. In this case, the energy that is not consumed can be injected into the network and, in each billing period, the marketer will compensate the cost of the energy discharged.

To qualify for this class, the primary energy source must be of renewable origin and the total power of the production facilities may not exceed 100kW.



Type B:  facilities that do not meet the requirements to be classified in the previous categories.

What mode of self-consumption suits me?

This will depend on different factors, but the one that will mainly determine it is the contracted power:


  • Installations with powers of less than 15 kW: the majority of homes and small businesses, for which the best option is to take advantage of the simplified compensation system. The procedure will be simple, the marketer will compensate you at the end of the month for the energy consumed from the network with which you discharged.

Installations with powers between 15 kW and 100 kW: it will depend on the amount of surpluses and consumption that we have. In the event that we have a lot of excess energy, it would be convenient for us to compensate for the surplus, in the event that we have very different consumption throughout the year, it is interesting

Smart batteries. Do I need one in my photovoltaic panel installation?

Before thinking about batteries, let’s start from the basis that photovoltaic panel installations for self-consumption are made up of the following elements: solar panels, of course, an inverter, wiring, structures to anchor the panels to the roof or the ground and a monitoring system that measures energy production in real time.

Another point to bear in mind is that the vast majority of installations are connected to the electricity grid: a security measure so as not to run out of energy in the event that it has not been able to generate enough or that it has run out.

Therefore, smart batteries are not really an essential element in your self-consumption installation, although they are very useful.

There are times when your installation may generate extra energy or you may not consume all the energy you have generated. In this case, if you are connected to the network and you have a self-consumption installation with surpluses, you can dump the excess and you will receive compensation on your bill.



Another option is to have smart batteries that save that excess energy for another time when you need it; they will only send power to the grid when they are fully charged. In this way, not only do you ensure that you optimize the energy generated in your installation to the maximum, but you also increase your  independence  from the electricity grid.

Although these batteries are  quite expensive , you will accelerate the recovery of the investment you have made in the installation, since you will not have to pay anything (or a minimum) to the energy marketer, as you did before. Not to mention that you generate even less waste, since you optimize self-generated waste to the maximum.

Moving towards greener models of generating energy continues to be a challenge, but technological development is going faster and the level of awareness is increasing. Join the change now and start saving as soon as possible!

At SotySolar we can help you  calculate what you would save  thanks to the disposal of surpluses totally free. Ask us for your personalized study and we will send you all the necessary information so that you can assess whether it is worth installing solar panels on your roof or not.


Below Article Content Ad

Related Articles

Back to top button
Hello there
Leverage agile frameworks to provide a robust synopsis for high level overviews.