Summary: since the photovoltaic panels were installed on the roof, we have been living pending the sky and a
mobile
app .
The ideal is to concentrate as much electricity consumption as possible in the hours with the highest solar production.
This chart for a day in August nicely sums up how it works:
The green plot is the electricity produced by the panels.
If I don't overdo it, all the consumption I do during these hours is free.
At night my panels are not active and the electricity I consume I have to pay to my electric company.
5 kW
4
they discount me
to overturn
to the network the
electricity
spare
I pay what
consumption
above
3
2
one
self-consumption
0
4.00
8.00
12:00
16.00
20.00
Source: FusionSolar with data from my consumption
electricity last August 12.
At night my panels are not active and the electricity I consume I have to pay to my electric company.
The green plot is the electricity produced by the panels.
If I don't overdo it, all the consumption I do during these hours is free.
5 kW
I pay what
consumption
above
4
I am discounted for
dump the network
surplus electricity
3
2
one
self-consumption
0
0.00
4.00
8.00
12:00
16.00
20.00
Source: FusionSolar with data from my electricity consumption last August 12.
I have put photovoltaic panels in my house, in the mountains of Madrid.
I am part of the citizen wave that in 2022 has pulverized the record for self-consumption solar installations in Spain.
Although there are no statistics on the number of homes with solar panels, the Association of Renewable Energy Companies (APPA) estimates that in a single year the photovoltaic self-consumption that there was so far in the country has practically doubled (from 2,742 megawatts (MW) to 5,200, a capacity equivalent to that of five coal plants).
And of all these installations, he calculates that between 35% and 40% of the solar megawatts are placed on private roofs.
In my case, the wait lasted several months beyond the scheduled date until the installer's van appeared on the dirt road, as they told me, because it could not cope with the avalanche of requests.
But, finally, on May 5, it launched photovoltaic panels: 12 plates that add up to 4.5 kilowatts of power, a size large enough to cover the needs of a home where almost everything works with electricity (not just light and appliances, but also heating, hot water and the car).
It's like having a small power station on the roof, which works, yes, as long as the sun shines in the sky.
Solar panels on the roof of my house.Santi Burgos
The main motivation in our house to invest in solar energy has been to reduce as much as we can the emissions that cause global warming.
But, as in many other homes, the dizzying rise in the electricity bill has also had a lot to do with it and, of course, the enormous aid launched from the European Union to promote this type of energy, which neither pollutes nor depends on third parties. countries.
Our entire photovoltaic installation has cost 8,460 euros (VAT included), but we continue with the administrative process to receive a subsidy of 2,736 euros, so we expect it to come out for 5,724 euros.
These subsidies for self-consumption are part of the package of 1,320 million euros distributed by the central government through the autonomous communities, and expanded in October with an additional 500 million.
Once the plates are on, we celebrate at home with a meal cooked entirely with the energy of the sun.
It seemed to us that we had taken a leap in time.
However, for the biggest change we had to wait another three months until the installation was registered in the Industrial Registry of the autonomous community.
After being informed of the distribution company and the retailer to which we pay our electricity bills, we finally went from being mere consumers of electricity to also becoming self-producers.
From then on, a new section appears on the bills: after the block in which the amount of energy that we must pay to the electricity company is stated, there is now the amount that must be deducted from us for the excess electricity that we inject into the network (yes,
15.00
solar surplus
overturned to the network
When there is enough sun, the house is not only supplied with the energy from the plates, but it can also turn the surplus generated into the general electrical network and obtain compensation for it at the end of the month.
18.00
Mixed consumption:
panels and conventional network
On the other hand, if the production of the panels is not enough or the consumption is too high to be covered with solar energy, then the house draws on the conventional network, having to pay the electricity company for those kilowatt hours.
15.00
solar surplus
overturned to the network
When there is enough sun, the house is not only supplied with the energy from the plates, but it can also turn the surplus generated into the general electrical network and obtain compensation for it at the end of the month.
18.00
Mixed consumption:
panels and conventional network
On the other hand, if the production of the panels is not enough or the consumption is too high to be covered with solar energy, then the house draws on the conventional network, having to pay the electricity company for those kilowatt hours.
15.00
When there is enough sun, the house is not only supplied with the energy from the plates, but it can also turn the surplus generated into the general electrical network and obtain compensation for it at the end of the month.
solar surplus
overturned to the network
18.00
On the other hand, if the production of the panels is not enough or the consumption is too high to be covered with solar energy, then the house draws on the conventional network, having to pay the electricity company for those kilowatt hours.
Mixed consumption:
panels and conventional network
The September bill was quite a surprise: for the energy used from abroad we had to pay 58.02 euros, but the surplus electricity generated by ourselves came to 63.67 euros.
That month, our electricity was free and we only had to pay the fixed costs and taxes.
Total bill: 14 euros.
Although most people do not live in houses with their own roofs, but in flats in apartment blocks, this works exactly the same when it comes to collective self-consumption in a community of neighbors.
"The biggest difference in a collective photovoltaic installation is that the process to obtain compensation is much longer, but then each neighbor can also pass on the surplus savings on their bill, depending on the power distribution agreed upon in the community" , explains Laura Feijoó, coordinator of the self-consumption area of the company Ecooo.
"The savings will depend a lot on the size of the roof and the number of neighbors, but the bill works the same," she says.
Invoice with compensation
of surplus electricity
Since we are authorized to transfer the electricity produced by our panels and that we do not consume to the grid, our invoice includes a section with the discount that the company must apply to us (September invoice).
Fixed costs
€12.72
Consumption
€58.02
Surplus
solar
-€63.67
The solar discount is usually only applied on the energy consumed, but not on fixed expenses and taxes.
Taxes
€2.25
Total
€14.97
The electricity that I feed into the network is paid cheaper than what I consume from the network.
€/kWh
Tip
0.357
Which
I pay
Flat
0.293
0.241
Valley
Which
they pay me
Tipped over
to network
0.187
Invoice with excess electricity compensation
Since we are authorized to transfer the electricity produced by our panels and that we do not consume to the grid, our invoice includes a section with the discount that the company must apply to us (September invoice).
Fixed costs
€12.72
Consumption
€58.02
The solar discount is usually only applied on the energy consumed, but not on fixed expenses and taxes.
solar surplus
-€63.67
Taxes
€2.25
Total
€14.97
The electricity that I feed into the network is paid cheaper than what I consume from the network.
euro/kWh
Tip
0.357
what i pay
Flat
0.293
Valley
0.241
Tipped over
to network
what they pay me
0.187
Para reducir lo que se paga en electricidad, lo primero es controlar nuestro consumo, pero con unas placas fotovoltaicas también depende mucho de las horas del sol que haya en el mes y de la atención que pongamos en casa para usar los electrodomésticos y el resto de equipos en los momentos del día con más energía solar disponible. Para esto último hay que estar pendiente de una app en el móvil que muestra en tiempo real la producción solar y el consumo eléctrico de la casa (esto también cambia en el autoconsumo compartido, donde estos sistemas de monitoreo están todavía menos evolucionados). Los másfrikis con placas solares en casa desarrollan ellos mismo sus propias herramientas de medición.
¿Se puede conseguir bajar la factura de la luz a cero euros? Por lo general, las comercializadoras eléctricas aplican el descuento por el sobrante de energía solar únicamente sobre la parte a abonar por la energía consumida de la red y no sobre el total de la factura. Así pues, el descuento no puede ser mayor de esa cantidad (aunque se haya volcado a la red mucha más electricidad de la consumida) y siempre hay que pagar la parte fija y los impuestos. Sin embargo, hay comercializadoras eléctricas que ofrecen lo que denominan una batería virtual o cuenta verde, donde sí se puede descontar todo el excedente solar en el total de la factura o incluso, si es todavía mayor, de la factura del mes siguiente.
Con todo, esto puede ocurrir solo en los meses con más sol y resulta sobre todo interesante para particulares que tengan mucha producción de energía solar, pero muy poco consumo eléctrico. En mi caso, me sale mucho más a cuenta aprovechar todo lo que pueda la generación solar durante el día para cubrir la demanda de la calefacción o la recarga del coche, aunque aumente el consumo y no deje excedente. Pago más de factura eléctrica, pero me olvido de combustibles más caros y contaminantes como el gas o la gasolina.
Tampoco hay que pensar que todas las facturas van a ser tan baratas, pues en los meses de invierno se reducen mucho las horas de sol. La de septiembre fue de 14 euros, pero la de noviembre nos devolvió a la realidad: 170 euros (con una compensación por el excedente solar de -21,6 euros). Esto ocurre por la menor producción de las placas y por haber puesto en marcha la calefacción eléctrica (aparte de las recargas del coche). Diciembre es peor, los termómetros marcan por primera vez temperaturas bajo cero y dejamos de ver el sol durante varias semanas. En casa nos ponemos en modo ahorro: hay que abrigarse más. Afortunadamente, en España son más los meses con sol que los de cielos nublados.
En los papeles del proyecto de nuestra instalación solar se aseguraba que las 12 placas fotovoltaicas puestas en el tejado nos permitirían alcanzar un 56,4% de autarquía eléctrica. Pero superados nuestros primeros 250 días como productores de energía solar, la app del móvil dice que el consumo de la casa todavía depende un 57,17% de la electricidad importada de la red. Una opción para aumentar nuestro consumo solar sería poner también baterías. “Yo tengo dos kilovatios de paneles y una batería de cinco kilovatios hora”, cuenta el experto en energía Francisco Valverde, que detalla que estos acumuladores de energía no sirven de momento para conseguir una autonomía plena, pero sí son un apoyo muy interesante para alargar más tiempo en el día el uso de la energía solar, incluso de noche. Aunque si no hay sol para producir energía, tampoco para acumularla. “El mes de diciembre ha sido… nefasto, no; lo siguiente. Ha estado nublado casi todos los días”, se queja este especialista del mercado eléctrico, que asegura que cuando no puede almacenar energía solar, utiliza la batería para acumular electricidad de la red cuando está a precios más bajos (con una tarifa regulada PVPC).
Sin intentar llegar a la autosuficiencia energética, nunca se habían instalado tantas placas solares en tejados en España como ahora. De hecho, la organización APPA estima que el país puede alcanzar en 2024 los objetivos de autonconsumo solar marcados para 2030. Cada vez somos más los ciudadanos pendientes del sol para encender la lavadora. No siempre es fácil, pero como recuerda Valverde, aquí hay mucha más radiación solar que en otros países europeos del norte, donde llevan 40 años poniendo placas en las casas: “Una misma instalación fotovoltaica produce en Madrid un 53% más que en Berlín”, incide.
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