Commercial Solar - Mijas
20kW commercial solar on a Mijas Golf Club building — three-phase SMA Tripower inverter, commercial CAU for surplus compensation, and IBI discount on the energy efficiency certificate.
By Ben Hayden
Project Overview
The Challenge
This Mijas commercial building — a 2,800m² business park with 6 business units, shared parking, and common area infrastructure — wanted to address electricity costs that had reached €38,000 per year across all tenants. Individual solar installations per unit would have been impractical: roof space was limited and the shared electrical infrastructure meant each unit would need its own grid connection upgrade. The building owner's vision was a single large solar installation on the shared roof, with surplus shared between tenants via a collective self-consumption agreement — a model permitted under Spain's RD 244/2019 collective self-consumption regulation.
The Solution
50kW commercial solar installation for a retail centre with grid connection. Daytime self-consumption varies with the centre's demand and solar production.
Technical Specifications
- 100 x 500W Trina Solar Vertex panels
- Huawei SUN2000-50KTL-M3 commercial inverter
- Three-phase grid connection
- Real-time power monitoring dashboard
- 25-year performance warranty
Our Installation Process
Collective Self-Consumption Agreement Design
We designed a collective self-consumption sharing coefficient for all 6 business units under RD 244/2019. Each unit's coefficient was set proportional to their average consumption share (audited over 12 months), meaning the largest consumer receives the largest proportion of solar generation credit. The agreement was registered with Endesa and the Junta de Andalucía before installation commenced.
50kW Rooftop System Design & Installation
The flat commercial roof was surveyed for structural capacity and solar potential. A 50kW system (100 × 500W panels) was laid in landscape orientation on aluminium ballasted frames — no roof penetrations. Individual string MPPT inverters were installed per section to prevent shading on one part of the roof affecting overall system performance. The system generates approximately 75,000 kWh per year in Mijas.
Smart Metering & Tenant Allocation System
Bidirectional smart meters were installed at each unit's supply point to measure both consumption and allocated solar generation. Monthly reports showing each tenant's solar allocation and grid import are automatically generated and shared with the building administrator. The system was designed to be expandable — additional panels can be added in future without requiring changes to the metering or sharing agreement.
CAU Registration, PVPC Report & Commissioning Handover
The 50kW collective self-consumption installation was registered with Endesa under the PVPC collective framework — a process that required 3 separate CAU codes (one per inverter string) to be submitted simultaneously for the sharing agreement to activate correctly. The Boletín Eléctrico was completed by our Senior Electrical Engineer and submitted to the Delegación de Industria covering both the DC generation circuit and the AC connection. Each business unit owner received a commissioning report showing their individual solar allocation coefficient, estimated annual generation allocation, and projected annual grid import reduction. The building administrator received a complete package of compliance documentation including the refrigerant installation certificate, structural load calculations, and Endesa grid connection approval.
Results
See the installation scope and equipment below; no financial outcome is promised.
Backed by Research
References for checking the proposed design. These sources do not certify this project's performance, savings, eligibility or commissioning records.
Estimate solar yield for the actual site
Annual generation depends on location, orientation, tilt, shading and system losses. An irradiance figure is not a guaranteed yield per installed kilowatt. State the assumptions and compare the estimate with the property's consumption.
European Commission — PVGIS ↗Check the applicable self-consumption arrangement
RD 244/2019 regulates administrative, technical and economic conditions for self-consumption. Export compensation is subject to the applicable arrangement and contract; exported energy is not automatically valued at the retail import price.
BOE — RD 244/2019 ↗Tax relief needs separate eligibility checks
Do not assume solar qualifies for an income-tax deduction or a standard municipal IBI discount. Check current AEAT conditions and the property's municipal ordinance, required evidence, dates and application process before including an incentive in a budget.
Agencia Tributaria — current tax guidance ↗Collective self-consumption agreements in Spanish commercial buildings look straightforward on paper — until you're dealing with 6 different tenants, 6 different lease structures, and one landlord who's realised he should have put this in the leases from the start. We drafted the coefficient allocation agreement and took it through two revisions with the tenants' lawyers before a panel was installed. The technical work here was simple. The legal framework took four months.
Frequently Asked Questions
Related Services
LIT services in Mijas directly related to this work.
About the Author
Ben Hayden is an English speaking electrician and independent energy advisor based in Marbella, Spain, with over 15 years of electrical experience across Europe. He provides independent energy and electrical checks for overseas property owners and managers across the Costa del Sol — helping clients cut electricity bills, navigate Spanish regulations, and make confident decisions on solar PV, heat pump, EV charger and battery storage projects. Ben advises in plain English on projects where the paperwork is in Spanish and the stakes are high. His writing has appeared in ExpatArrivals, The Olive Press, Euro Weekly News, BuildingTalk and pv magazine.
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Quote ConfiguratorProject Details
- Location
- Mijas, Málaga
- Completed
- September 2025
- Service
- Solar
- Author
- Ben Hayden
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