La Quinta, Málaga · real owner data
Four years with solar and a battery in rural Spain.
What the system cost, what it produced in a complete year, what one real bill reveals, and why we added west-facing panels in 2026.
We installed the original system in 2022, after the rise in energy prices around the start of the war in Ukraine made our exposure to electricity costs impossible to ignore. It serves a rural home and holiday rentals near Frigiliana. After four years of using it, my view is simple: “Best money I have ever spent.”
Important: this is one owner’s experience, not a forecast or sales claim. Roofs, shading, weather, occupancy, tariffs, equipment and installation quality all change the outcome. My four-year payback statement is a personal calculation based on the value of energy produced, not an audited financial return or a guarantee for another property.
1. The system installed in 2022
The original installation used 12 panels rated at 455 W each, giving 5.46 kWp of panel capacity. The panels are split across two nearly south-facing roof sections and two strings. A Huawei 5 kW inverter manages the array, paired with a Huawei 5 kWh battery.
| Component | Installed specification |
|---|---|
| Solar array | 12 × 455 W = 5.46 kWp |
| Orientation | Two near-south roof sections |
| String layout | Two strings |
| Main inverter | Huawei, 5 kW |
| Battery | Huawei, 5 kWh |
| Installed | 2022 |
| Original installed cost | €10,000 including VAT |
| Grant or subsidy | None |
The battery can supply backed-up circuits during an outage through island-mode equipment. That backup switch was added later for €350. It was a resilience decision as much as an energy-saving decision: the local grid can be unstable, and the home supports guests as well as normal household demand.
2. Why contracted power still matters
The supply contract shown on the bill reviewed for this case study has 8.05 kW of contracted power in both tariff periods. Having sufficient contracted power has been particularly useful for the holiday-rental loads when solar is weak or unavailable.
Solar does not increase the contracted potencia. It can, however, serve part of the property’s demand behind the meter while the grid serves the remainder. In strong sun, I have observed the PV system contributing roughly 5 kW, with the battery able to add power when it has charge. The exact combined limit depends on the inverter, battery, backup arrangement and electrical installation, so this should not be treated as universally available extra capacity.
3. A complete year: the verified 2025 result
For a clean annual comparison, 2025 is the most useful year because it covers January to December and predates the May 2026 expansion. The Huawei monitoring screen records 9.87 MWh of production and 13.45 MWh of total household consumption.
| Measure | Energy | Share shown |
|---|---|---|
| Total solar production | 9.87 MWh | 100% |
| Production consumed on site | 6.88 MWh | 69.78% of production |
| Production fed to grid | 2.98 MWh | 30.22% of production |
| Total household consumption | 13.45 MWh | 100% |
| Consumption supplied from PV | 6.81 MWh | 50.65% of consumption |
| Consumption supplied from grid | 6.64 MWh | 49.35% of consumption |
Open evidence
Download the figures and reproduce the checks
The CSV contains the displayed annual totals, the May 2026 bill lines and clear source labels. It does not contain an address, account number, CUPS, meter identifier, bank details or the contract holder’s name.
6.88 ÷ 9.87
The monitoring app displays 69.78% of production consumed on site. Values shown in MWh are rounded, so reproducing the calculation from those rounded values gives an approximate result.
6.81 ÷ 13.45
The app displays 50.65% of household consumption supplied from PV. The remaining displayed share, 49.35%, came from the grid.
The two sides of the monitoring screen use slightly different energy-flow categories: 6.88 MWh of production is labelled consumed, while 6.81 MWh of household consumption is labelled from PV. Small differences can arise from rounding and the way battery conversion or energy flows are accounted for. Rayte has preserved the displayed values rather than silently forcing them to match.
Subtracting annual exports from annual imports gives about 3.66 MWh of net grid import for context. That is not how the bill is calculated: imports and exports are separately measured and valued at different prices.
4. What one real May 2026 bill teaches
An anonymised Gana Energía bill for a 26-day period in May 2026 provides a useful test. The home imported 438.50 kWh but exported 491.75 kWh. Exported energy therefore exceeded imported energy in kWh, yet the final bill was not zero.
| Bill line | Quantity and rate | Amount |
|---|---|---|
| Peak import (P1) | 17.07 kWh × €0.171/kWh | €2.92 |
| Shoulder import (P2) | 29.09 kWh × €0.104/kWh | €3.03 |
| Off-peak import (P3) | 392.34 kWh × €0.080/kWh | €31.39 |
| Solar export credit | 491.75 kWh × €0.060/kWh | −€29.50 |
| Energy charge after export credit | Import cost less export credit | €7.84 |
| Contracted-power charge | 8.05 kW P1/P2 for 26 days | €37.44 |
| Final bill | After meter rental, social-bonus contribution and taxes | €59.06 |
The practical lesson
More exported kWh did not mean a zero bill
- Imported
- 438.50 kWh
- Exported
- 491.75 kWh
- Export value
- €29.50 credit
- Power charge
- €37.44
Imported energy cost more per kWh than exported energy earned, and compensation did not remove the contracted-power charge, meter rental, levies or taxes. The €0.060/kWh export figure is the rate on this contract for this billing period, not a universal government-set rate for every supplier.
A virtual-balance facility is associated with the supply arrangement, but this particular bill does not show a separate €4 service charge. I recalled a fee of about that amount, but Rayte is not presenting it as verified until the current contract terms or another bill confirm it. The virtual-battery guide explains why contract evidence matters.
5. How the battery is actually used
On clear days the battery normally reaches 100% from the panels. The system is programmed automatically: it stores surplus during the day and releases energy during the expensive period. When solar is insufficient, it can also charge from the grid in a cheaper period for later peak use.
The exact backup-reserve setting is intentionally not published. What matters for another homeowner is the trade-off: energy held in reserve improves outage resilience but cannot simultaneously be counted as energy available for tariff arbitrage. Any comparison should keep the same reserve and charging rules across the tariffs being tested.
6. Rural-grid stability is a real operating issue
The most persistent practical problem has not been the panels or battery. It has been occasional over-voltage or under-voltage on the incoming grid. The inverter then shuts down to protect the installation and comply with its grid limits. That can interrupt production even on a sunny day.
This is not a reason to widen protection settings yourself. Repeated events should be documented with timestamps and error codes, then raised with the installer and distribution network operator. Protection settings and grid-code parameters should only be handled by qualified professionals.
The separate grid-voltage shutdown guide explains what to record, what the installer should investigate and when the distributor becomes the right contact.
7. The May 2026 expansion
In May 2026 we added eight 500 W panels, another 4.00 kWp. They face west and have clear afternoon exposure. The purpose was not simply to increase a daily total; it was to extend generation later into the day, closer to the property’s afternoon and early-evening demand.
The eight panels were supplied as a gift after I referred other projects to the installer. That makes this expansion unsuitable for a normal cost-payback comparison, so I do not combine it with the €10,000 cost of the original 2022 system or present a market price for the extension.
The extension uses a Huawei 3.5 kW secondary inverter. The original 5 kWh battery remains unchanged. The current installation therefore has 20 panels, 9.46 kWp of panel capacity and 8.5 kW of nominal inverter capacity across the main and secondary inverters.
| Configuration | 2022 original | From May 2026 |
|---|---|---|
| Panels | 12 | 20 |
| Panel capacity | 5.46 kWp | 9.46 kWp |
| Orientations | Near south | Near south + west |
| Inverters | Huawei 5 kW | Huawei 5 kW + 3.5 kW |
| Battery | Huawei 5 kWh | Unchanged at 5 kWh |
Because 2026 contains two configurations—January to April with the original array and May onward with the extension—it is not a like-for-like annual comparison with 2025. A proper assessment of the west-facing addition needs a complete post-expansion year and should adjust for weather and demand changes.
8. Lifetime monitoring through August 2026
The anonymised lifetime screen, captured in August 2026, records 44.83 MWh of production since the system began operating. It also records 52.87 MWh of household consumption. These totals span both the original configuration and the partial year after the expansion.
| Measure | Energy | Share shown |
|---|---|---|
| Total solar production | 44.83 MWh | 100% |
| Production consumed on site | 31.14 MWh | 69.45% of production |
| Production fed to grid | 13.70 MWh | 30.55% of production |
| Total household consumption | 52.87 MWh | 100% |
| Consumption supplied from PV | 30.84 MWh | 58.33% of consumption |
| Consumption supplied from grid | 22.03 MWh | 41.67% of consumption |
9. My payback view—and its limit
The original installation cost €10,000 and received no grant. Based on my own calculation of the value of electricity the system produced and displaced, I consider that original cost to have been recovered after about four years. The €350 backup switch came later and was purchased for resilience.
That is an owner assessment, not a promise of a four-year financial payback. A formal calculation would need dated tariffs, every bill, export compensation, degradation, maintenance, financing, taxes and the counterfactual cost of electricity without the system. Rayte publishes the statement because it honestly describes my decision; it labels the limitation because another household may get a very different result.
10. What I would carry into another project
- Design around the household’s hourly demand, not only an annual kWh total.
- Use orientation deliberately: the west-facing extension aims to cover later demand.
- Keep grid import, grid export, inverter production and bill credit as separate measures.
- Model contracted-power charges and taxes even in months with strong exports.
- Treat battery backup and tariff savings as related but different benefits.
- Log grid-voltage faults and involve the installer or distributor rather than changing protection limits.
- Use a complete year before making a strong before-and-after claim.
Evidence, method and official framework
- Owner’s Huawei monitoring records: full-year 2025 and lifetime snapshot captured in August 2026; anonymised copies reproduced on this page.
- Owner’s May 2026 Gana Energía bill: figures transcribed for analysis; the original bill is not published because it belongs to another named contract holder and contains private financial and supply identifiers.
- Downloadable case-study data — a machine-readable transcription of the published figures and their source status.
- Rayte — smart-meter and solar data reconciliation method
- BOE — Royal Decree 244/2019 on self-consumption
- IDAE — practical self-consumption guide
Reviewed 28 August 2026. Monetary figures include the euro amounts shown on the source bill. Monitoring figures are displayed values and may reflect manufacturer rounding. This page is editorial information, not personalised financial, electrical or installation advice.