IDAE (Institute for Diversification and Energy Saving), under the Ministry of Ecological Transition and Demographic Challenge, has among its various publications (such as the ‘Self-Consumption Roadmap’) ‘The Practical Guide to Becoming a Self-Consumer in 5 Steps, whose presentation highlights the ‘low Prices of some renewable technologies, especially solar photovoltaics, which have reduced costs by 80% in five years, and the commercial development of storage using batteries.”
The possibility of saving not only for the consumer (repayments are estimated between six and ten years), but also for other consumers, “because self-consumption contributes to Reducing the market price of electricity: on the one hand, by reducing demand (those who consume themselves buy less energy from the grid) and on the other, by increasing the supply of renewable energy (if there are surpluses, there is more energy circulating in the electric market).” This era led New from energy consumption to all kinds of uncertainties, such as the one we are trying to solve below.
– What should be taken into account when proceeding with the installation of self-consumption energy from photovoltaic sources?
From Plenitude, they comment on the many factors to consider when evaluating an installation, and what wattage to count on: «Watts of the panel, shown in the catalog or on the label; Sun hours received by the place where the panel is to be installed, and sunshine in the place where the installation is to take place (in general, each hour of sun produces a Wh value similar to that of the unit size). With regard to extension, in the sector it is recommended to allocate no more than 8 m2 per kilowatt of energy. In terms of benefits and coverage from IDAE it indicates “how a 3 kilowatt system can cover most of the lighting needs and electricity consumption of a family of four and a 70m2 area”.
– How much does it cost to install solar panels at home?
Francisco Javier Gallardo, director of self-consumption at Capital Energy, highlights the importance of installation on a roof or apartment, as well as the materials, the roof and, of course, the location of the house. «In any case (points Gallardo), the cost will vary between 5,000 and 12,000 euros, depending on the strength of the installation. Most homes are closer to 5,000 than 12,000, which already corresponds to homes with wind-heating, under-floor heating, etc.” If we refer to the duration of the paintings, averages are estimated from 20 to 25 years, which can sometimes reach forty.
What aids and subsidies are available for this type of facility?
In Spain there are different aid and support programs for this concept, both for households and companies, as outlined by Capital Energy: «There are the subsidies offered by IDAE, which redistribute NextGen funds, as well as regional assistance programs for self-consumption. There are also soft loans to finance the installation of solar panels in homes. Finally, only some transitional areas also have special help. Aid that can, at present, be deducted in the IRPF, in addition to the exemption from the property tax (IBI) and the electrical energy production tax (IPPE), in addition to the ICIO bonus (construction tax, installations and works).
What types of facilities are there? How much energy can they produce?
They point out in an abundant document that “self-consumption patterns are described in Article 4 of RD 244/2019: without surpluses, where the energy is not transferred to the distribution or transmission network; with surpluses (subject to compensation, where the energy is diverted to the network which is subsequently compensated in the consumer bill) and with surpluses, not subject to compensation, since the energy is transferred to the network that is sold on the electric market. They are also called isolated (networked, they only consume what they generate) and networked.
Are there different types of panels?
In fact, as they explain from Otovo: “Monocrystalline solar panels are mainly used (with greater efficiency and performance and are the best choice for residential installations, where space is often limited). But there are also polycrystalline or amorphous solar panels (made obsolete due to the lower performance they provide), differentiated by the number of crystals and their arrangement in the installation. You can also get thermal solar panels for self-sufficiency. These are mainly used to heat sanitary water. In addition, there are hybrid solar panels that combine the two technologies.
How do I compensate for my excess energy generation?
According to the sources consulted, the customer notifies the distributor that they have an installation and that they may have excess, and with permission, the process begins, both traditionally and with “virtual batteries” (a form of management without the need for physical equipment, not even digital support). “The unconsumed solar energy (which they refer to as Plenitude) is returned to the grid and the energy supplier will pay for it according to the redundancy compensation mechanism. In our case, we pay the unconsumed excess energy at one of the best rates on the market (0.150€/kWh). And if there is an installation batteries, these surpluses can be stored for their own use.
– Can solar panels be installed on the roof of the building or only in individual homes?
“Not only could it be possible (Gallardo highlights), but it is currently a widespread practice among neighboring communities, that a high percentage of IBI can be saved in many municipalities for several years.” In the case of owner communities, the energy produced is distributed among the homeowners in the community, which will reduce electricity consumption and the community bill.
How is the energy I produce and the energy I consume measured?
“The energy produced by the solar panels (Gallardo adds) is measured by a two-way meter, which records both the energy consumed from the electrical grid and the energy generated and injected into the grid. In addition, there are monitoring devices that allow the user to know the installation process in real time and the amount of energy produced and consumed.
– What kind of companies do you find most profitable to do the photovoltaic project? What are the key questions to consider in order to decide whether it is worth undertaking a project of this nature?
«For those (says Ana Resquez, from Carrera) who have a high energy consumption, and have a sunny roof where they can locate the panels. No matter whether the price of electricity is higher or lower at present, you have to think that the installation of self-consumption photovoltaic cells is a “hedge” against market fluctuations. He will be able to provide a percentage of the energy needed by the company at a certain cost that is stable over time.”
– What kind of guarantees are there in these facilities, except for the faults that may arise?
Rízquez states that “the guarantee of production must depend on the performance of the installation, which depends on the quality of its components and the electrical installation itself. The external factor that we must measure is the radiation that is received in that area. We obtain this data by installing a calibrated photocell. Using the cell Calibration, we check, based on the radiation already received in a given plane with the same direction and inclination as the solar panels, the expected performance is achieved.