Switzerland is experiencing a meteoric transition towards electromobility. With a market share of electric vehicles (EV) and plug-in hybrids breaking records every year, the Swiss automotive landscape is transforming. If charging an electric car in an individual villa is today a standard and well-controlled procedure, the situation takes a radically different turn when it comes to a multi-family building or a Property by Floors (PPE).
In a shared underground car park with 10, 20 or 50 spaces, the chaotic installation of individual charging stations inevitably leads to a technical disaster: overloading the main electrical connection of the building, leading to the disconnection of the entire building. To prevent this blackout, a technology is now establishing itself as the essential standard: dynamic load management (DLM).
But the real revolution comes when this intelligent charging infrastructure is coupled with a photovoltaic installation on the roof of the building. By synchronizing solar production with vehicle charging, co-owners maximize their self-consumption, drastically reduce their electricity costs and circumvent the limits of the public network.
This guide is designed for co-owners, PPE committees, building owners and managers who must decide what to buy, how to vote for it and how to invoice it. It dissects the technical challenges of multiple charging, details how dynamic solar charge management works, explores automated billing solutions, and guides you through the legal framework and subsidies available in Switzerland.
1. The Electrical Bottleneck: Why Do Buildings Trip?
To understand the urgency and necessity of Load Management, we must first analyze the electrical anatomy of a standard Swiss apartment building.
The physical limits of the connection (overcurrent cut-off)
Each building is connected to the public electricity network (managed by the local Distribution Network Manager, such as Romande Energie, SIG or BKW) via a main cable sized according to the historical needs of the building. This connection is protected by main fuses (general overcurrent cut-outs).
In a building built 20 or 30 years ago, the electrical engineer calculated the power needed for lighting, elevators, heating, and domestic consumption (ovens, washing machines). It was never planned that a fleet of electric vehicles would be connected there.
The mathematics of overload
Let's take a concrete example: a building of 15 apartments. A standard charging station (three-phase alternating current) delivers 11 kW or 22 kW of power. If 5 residents come home from work at 18h00 and simultaneously plug their cars into non-smart 11 kW terminals, the instantaneous demand for the parking lot jumps by 55 kW. At this same time, the other residents turn on their ovens, their hobs and the heat pump is running at full speed.
The result is inevitable: The total intensity (in Amperes) exceeds the capacity of the main connection of the building. The main fuses blow or the main circuit breaker trips, plunging the entire building into darkness.
The false good idea: Increase the power of the connection
The first reaction of a PPE committee to this problem is often to ask the DNO to increase the size of the building's main electrical connection (from 100 A to 250 A). Although technically possible, this solution is financially very burdensome:
- Civil engineering costs: The road often has to be dug up to run a new cable from the local substation.
- Connection fees: The DSO charges high equipment taxes for each additional Ampere.
- Increased power rate: The building will pay a significantly higher power tax (kW) each month.
2. What is Dynamic Load Management?
The Load Management is an intelligent system – hardware and software – that distributes available electrical power equitably and securely between multiple charging stations, without ever exceeding the building capacity limit.
A. Static Load Management
In a static system, a fixed power is permanently allocated to the parking lot (for example, 44 kW in total). If only one car is plugged in, it charges at 11 kW. If five cars plug in, the system divides the power: the terminals limit the current to around 8,8 kW each. It is a rigid system because the parking lot remains limited to 44 kW even at night when the rest of the building consumes almost nothing.
B. Dynamic Load Management (The optimal solution)
Dynamic management takes into account the consumption of the entire building in real time :
- The smart meter: Measures the total electricity consumed by the building every second.
- The brain (Charge controller): Communicates with terminals to adjust available power.
- Real-time adaptation: If the limit is 100 kW and the apartments consume 80 kW at 19h, the parking lot only receives 20 kW. At 2h in the morning, when residents are sleeping and the building only consumes 10 kW, the system releases 90 kW for charging.
The connection is thus 100% operated without work on the network. In addition, she manages thephase balancing (Phase Balancing), ensuring that the network is not unbalanced by single-phase vehicles.
3. The Perfect Alliance: Dynamic Management and Solar Energy
The real financial and ecological genius lies in the coupling of the charging system with a photovoltaic solar installation on the roof of the PPE. The concept of dynamic solar charge management allows excess solar production to be directed to the underground car park.
In Switzerland, the profitability of solar energy in buildings is based on self-consumption (RCP/ZEV). In the middle of the day, production is maximum but housing consumption is minimum. Instead of reinjecting this surplus at low cost into the network, the EMS (Energy Management System) automatically directs the energy to the charging stations. The charging speed continuously adapts to solar production (for example by varying from 6 A to 16 A depending on the passage of clouds). If necessary, charging is completed at night during off-peak network hours.
4. Physical Architecture: How to Wire an Underground Parking Lot?
Lack of planning often leads to wild connections from individual meters. This is a major technical error. To achieve successful integration, the Swiss standard SIA 2060 recommends the establishment of a common core infrastructure :
- The General Distribution Board (TGBT): An electrical panel dedicated exclusively to electromobility is installed in the technical room.
- The flat cable (ribbon wiring): A main cable runs through the ceiling of the car park. When a resident wishes to equip themselves, the electrician simply pinches this cable to install the terminal.
- The communications network: An Ethernet or mesh Wi-Fi network cable allows the terminals to communicate with the controller.
This architecture is clean, scalable and complies with AEAI fire protection requirements.
5. Billing and Cost Distribution: The ZEV / RCP Model
So that residents without an electric car do not pay for charging others, the building uses billing software solutions based on the RCP/ZEV model:
Each terminal is equipped with an RFID reader or an application to identify the user. A MID certified energy meter precisely measures the kWh consumed. The cloud software (e.g. Smart-me, Zaptec Portal) records this data and applies differentiated prices depending on the source of the energy (cheaper if it is solar, more expensive if it is from the public network). The statement is then generated automatically and transmitted to the management for integration into the charges (Nebenkosten).
6. The Legal Framework in Switzerland: The “Right to Take” in PPE
Switzerland does not have an automatic 'Right to take' enshrined in the Civil Code. A co-owner cannot install his or her individual terminal without the agreement of the community. The common basic infrastructure (flat cable) will be voted on in an assembly at the qualified majority (majority of people representing more than half of the thousandths).
In the event of refusal of financing by the PPE, it is possible to opt for the Contracting : an external service provider (or the DSO) finances and installs the cabling infrastructure, then charges a monthly usage subscription only to residents who equip themselves with terminals.
7. Cantonal Subsidies and Financial Aid
If the Confederation does not subsidize private terminals, the cantons and municipalities actively support the deployment of collective infrastructures with dynamic load management:
- Canton of Vaud: Subsidizes basic cabling infrastructure and provides bonuses for dynamic load management.
- Canton of Geneva: Offers aid via the Parking Foundation or collective equipment programs.
- Municipal actions: Many cities have specific subsidies to support projects combining solar and mobility.
8. Leading Technologies and Brands on the Swiss Market
The industry is moving towards open protocols (like OCPP) to ensure future compatibility:
- Zaptec (Norway): The terminal Zaptec Pro is the standard for PPE in Switzerland thanks to its dynamic phase balancing.
- Easee (Norway): Its boundaries Easee Charge easily communicate with each other in cascade.
- Smart-me (Switzerland): National leader for automated RCP meters and billing software.
Conclusion: Infrastructure as a Pillar of Tomorrow’s Real Estate
The electrification of the Swiss automobile fleet is inevitable. Dynamic solar load management makes it possible to add value to buildings while providing clean and very economical energy to residents. Installing a common cabled and managed infrastructure today is the best decision to perpetuate real estate assets in Switzerland.