From a Pioneer Installation to Modern Photovoltaics
As early as 1989, one of the first private photovoltaic systems was installed at the Eisenring house. At that time, solar power was genuine pioneering work: the cost per installed unit of capacity was many times higher than it is today, the technology was relatively simple, and practical operating experience was scarce. Nevertheless, the system proved itself over many years and reliably supplied solar electricity both for on-site consumption and for feeding into the public grid.
After almost 30 years of operation, however, it became apparent that the technical lifetime of the system had been reached. Spare parts were no longer available, particularly for central components such as the inverters. Continued operation was therefore no longer economically or technically viable. For this reason, a decision was taken to replace the entire system in 2017.
The new photovoltaic installation was not merely a replacement, but a fundamental further development. While the 1989 system cost were around six times per installed kilowatt, the 2017 system could be realised at significantly lower cost, with higher efficiency and greatly improved reliability. Modern modules, more efficient inverters and optimised system design have since enabled substantially higher energy production roof area.
More than Self-Consumption
With the new system, a significant proportion of the house’s electricity demand is generated directly on site. Self-consumption reduces the amount of energy drawn from the grid and improves the economic performance of the installation. At the same time, surplus energy is fed into the grid.
For the operator, financial return was never the sole priority. Every kilowatt-hour fed into the grid helps to reduce the need for electricity generation elsewhere – whether from fossil or other centralised sources. Especially in times of growing electricity demand, this represents an important contribution to decentralised energy supply.
These figures clearly show that since the commissioning of the home battery storage system in 2023, grid feed-in has been significantly reduced, self-consumption has almost doubled, and electricity drawn from the grid has been drastically reduced by around two thirds.
It was recognised early on that photovoltaics can only realise their full potential if systems are not restricted solely to self-consumption. Had solar installations always been dimensioned only to match on-site consumption exactly, only a fraction of today’s installed capacity would ever have been realised. Deliberate feed-in to the grid was and remains a central component of the energy transition.
Comparison of the 1989 and 2017 Solar Installations
The development of photovoltaics can be seen particularly clearly in the direct comparison of the two systems.
|
First Plant 1989 |
New Plant 2017 |
Ratio | ||
|---|---|---|---|---|
| Panels | ||||
| Length | [mm] | 1’293 | 1’686 | |
| Width | [mm] | 330 | 1015 | |
| Area per Panel | [m2] | 0.427 | 1.711 | |
| Number of Panels | [-] | 56 | 22 | |
| Nominal Voltage | [V] | 17.4 | 31.7 | |
| Nominal Current | [A] | 3.05 | 9.47 | |
| Nominal Power | [Wp] | 53.07 | 300.20 | |
| Weight per Panel | [kg] | 5.7 | 18 | |
| Module Efficiency | [%] | 12.41 | 17.5 | 141% |
| Plant | ||||
| Total Area | [m2] | 23.89 | 37.65 | 158% |
| Nominal Power total | [Wp] | 2’971.92 | 6’604.38 | 222% |
| Specific Power | [Wp/m2] | 124.38 | 175.42 | 141% |
The comparison shows unmistakably how dramatically efficiency, required area and output have changed within just under three decades – progress that would hardly have been possible without the early pioneer installations.
Subsidies and Amortisation
An important element of the financing consisted of subsidies, which covered around one third of the total system costs. Together with self-consumption and income from feed-in tariffs, around one third of the self-financed investment costs had been amortised by the end of 2025.
These figures show that although photovoltaic systems are designed for the long term, they can be operated economically under stable framework conditions. A key prerequisite for this is a degree of planning security, particularly with regard to remuneration schemes.
Feed-in Tariffs – An Uncertain Factor
At the time the new system was commissioned, the feed-in tariff of St. Gallisch-Appenzellische Kraftwerke (SAK, the local Power Utitlity) – including the green electricity bonus – was among the lowest in Switzerland. Nevertheless, feed-in was consciously accepted, as ecological benefit and contribution to security of supply were given greater weight than short-term financial return.
A central problem became apparent: feed-in tariffs fluctuated greatly and changed frequently, significantly impairing investment security. From 2018 to 2024 they rose from 4.73 SwissCent/kWh to 14.07 SwissCent/kWh, before beginning to fall again in 2025. The development was as follows:
Year CHF/kWh
2017 0.0545
2018 0.0473
2019 0.0526
2020 0.0623
2021 0.0943
2022 0.0943
2023 0.1407
2024 0.1607
2025 0.1380
This development demonstrates how strongly external framework conditions can influence the economic performance of a photovoltaic system – irrespective of technology, system design or operator behaviour.
Looking Ahead: New Regulation from 2026
At the beginning of 2026, a new regulation introducing variable feed-in tariffs will come into force. The concrete effects this will have on actual remuneration and on further amortisation of the system cannot yet be foreseen. However, there is justified concern that future tariffs may be lower and that the long-term economic viability of the system may no longer be assured.
This uncertainty exemplifies how important reliable political and regulatory framework conditions are for the continued expansion of renewable energies.
Pioneer Work as the Foundation for Today’s Progress
From the very beginning, the motivation behind these projects extended beyond the individual household. As early as 1984, Markus Eisenring was intensively engaged with solar energy and electromobility, including in the hobby-based construction of the Helios Wil solar vehicles.
With the early 1989 photovoltaic installation and the self-built electric vehicles Stromboli I and Stromboli II, it was demonstrated that decentralised power generation and everyday-capable electromobility were already possible long before today’s market maturity. Stromboli II has been in operation since 1996, is charged exclusively with solar electricity and remains fully functional to this day – an impressive proof of the sustainability of these early concepts.
This pioneering work helped to stimulate interest among the public and industry alike and paved the way for today’s widespread adoption of photovoltaics and electromobility.