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The national blackout that Spain has suffered It has been historicalbut has also sown the doubt. While the vast majority of citizens ran out of light, in the street there was “life” in some supermarkets or marques that made the use of other renewable alternatives. Surely also, today more than ever many will ask about the need to have a solar installation in their home, which leads us to another question: how does a network of domestic panels work before a national blackout?
Installation in normal conditions. Before talking about the case of a blackout as the one that occurred in Spain, it is convenient to explain the most basic of A “standard” installation In a typical home. In most cases, solar panels capture the radiation of the sun and generate what we call DC (DC). This current passes through an investor that converts it in turn in alternating current (CA), and that is precisely what we use in homes.
In Spain and in almost all countries, most solar facilities are connected to the electricity network (known systems as on-Grid). This allows, on the one hand, to consume solar energy directly in the house. On the other, pour the surplus to the network (which entitles economic compensation, such as the net balance or Simplified compensation). Finally, of course, it allows you to receive electricity from the network when there is not enough solar generation (for example, at night or on cloudy days).
The problem occurs when there is a situation like that occurred yesterday.
Installation in blackouts. When you have a photovoltaic installation in the house of only panels and there is a blackout, something contradictory but very important happens: even if you have solar panels working, the sky is sunny and the beginning of the day, your house is also It is left without electricity. As?
Yes, this occurs by security regulations (for example, in Europe under the standard VDE 0126-1-1 and similar), all solar investors connected to the network must detect the loss of tension and turn off immediately, is what is called Anti-Isla protection.
The reason? The reason for this “cut” is to protect network maintenance technicians: if there were thousands of houses by sending electricity to a supposedly “dead” network, it could be lethal for workers They are at that time repairing the failure. Therefore, if you have only solar panels connected to the network, you cannot use electricity during a blackout. Your solar panels are automatically disconnected. There is no more.
The solution: batteries. If you also have batteries, the thing changes, although here the situation varies depending on the type of investor and configuration you have. If you have hybrid investors (solar + battery), there are modern investors that already allow to continue operating in what is called Island or back-up mode. This means that when they detect a blackout, they are physically disconnected from the network and come to feed only your house using solar energy and energy stored in your batteries.
In addition, there are also systems for backup investors (The so-called back-up inverters), where a separate system is used that can feed a specific part of the house (for example, fridge, essential lights or internet).
One More Thing. But even so, for this to work you need lithium or lead batteries properly sizeda hybrid investor compatible with operation in island mode or an inverter with backup function (Back-UP), a automatic cutting system that separates your home from the public network in case of blackout guaranteeing safety, and finally an electrical panel prepared to isolate non-essential loads (for example, it makes no sense to keep the electric oven or air conditioning on if the energy is limited).
In any case and to place all this in perspective in the Spanish landscape, only 33% of facilities Current domestic lots in Spain include batteries. This means that most households with solar panels would continue to suffer electric cuts during a blackout like the one that occurred yesterday. The reasons are very varied, but the extra cost of investment of them after the solar installation (already large) is key.
The promise of self -supply. All this leads to a final question: Is it possible to be self -sufficient (energetically) in Spain? The short response is no. The promise of solar self -supply on the peninsula is based on taking advantage of the high solar radiation (Spain receives on average between 1,600 and 2,000 kWh/m²/year) to generate clean energy and reduce dependence on the electricity grid, especially in single -family homes.
Thanks to photovoltaic self -consumption and the Price drop Of the solar panels (more than 80% have fallen in the last decade), today it is technically possible to cover between 60% and 80% of the annual consumption of an average house in Spain only with solar energy, and in some cases, almost 100% If appropriate storage batteries are installed (although with the network hitch).
The problem. However, self -supply has important limits: solar production is intermittent (there is no generation of night and lowers a lot in winter or cloudy days), the batteries remain expensive (between 4,000 and 9,000 euros a complete domestic installation) and its capacity only allows a few hours or days of autonomy without network.
Plus: We already said it, the current legislation requires that the systems connected to the network be disconnected in blackouts if they are not equipped to function in Isla mode, which implies that, without a specific design (and of large disbursement), even with solar panels, you could run out of electricity in general cuts.
Image | Pxhere
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