Expert:innen: Christophe Ballif (CSEM / EPFL), Hartmut Nussbaumer (ZHAW), David Stickelberger (Swissolar)
Photovoltaics is the conversion of sunlight into electricity and is almost infinitely scalable. Its potential for generating electricity at locations in Switzerland is greater than current annual electricity consumption. The technology is mature, has a small ecological footprint, is well accepted by the general public and, with niche applications, offers excellent opportunities for Swiss firms. Despite these numerous advantages, it must be remembered that photovoltaics is not the only solution for the energy transition. In order to establish a secure and climate-neutral energy supply, other renewable energy sources, like wind, must also be used more, energy efficiency must be increased, and grids and storage facilities must be expanded further. In this context, Switzerland should be seen as part of a European energy system.
Picture: Bill Mead, Unsplash
The term "photovoltaics" (PV) means direct conversion of sunlight into electrical energy. A PV system is thus a solar power system in which solar cells convert part of the solar radiation into electricity.
The original applications were in spaceflight and in power supplies for small devices, such as calculators. Today’s applications can be divided into three categories: (1) Grid-connected systems, in which the generated solar power is used by the system itself, temporarily stored or fed into the general power grid and sold. These include the now widespread PV systems on buildings’ roofs and facades, but also ground-mounted systems and floating PV systems on lakes or at sea. (2) Stand-alone PV systems are used where there is no grid connection. They are a common self-sufficient energy solution for remote buildings, like mountain huts, but can also be used in urban environments, even though this specific application is not yet widespread. (3) Small devices, such as calculators, watches and wearables, constitute the third application category.
Today, the potential of PV is not exhausted and allows countless new applications. There is a growing, but still only small, proportion of PV modules being installed on facades. Building-integrated PV is set to play an increasingly important role: Here, PV modules are integrated into the building envelope, meaning the facade or roof, whereby their function goes beyond just electricity generation and incorporates aspects such as light guidance, sound insulation, thermal insulation, weather protection and aesthetics. New technologies have made it possible to respond very well to requirements regarding modules’ aesthetics.
Public spaces also offer good opportunities: Infrastructure encompasses large areas, including road canopies, noise barriers and dam walls, which can be equipped with PV systems. Initial pilot projects have been completed, such as AlpinSolar, in which solar modules were installed on the Muttsee dam wall. Large-scale landscape-compatible ground-mounted systems at alpine locations make it possible to further increase PV’s share of the electricity mix. These are of interest because they are situated in mist-free areas, produce electricity during winter and, thanks to the low temperatures and the sunlight reflecting off the snow, promise a high yield. However, they also entail major challenges, as hardly any such systems exist worldwide.
Mobile PV will be another application, for example the integration of solar cells on or in cars, lorries or ships. Although the first firms are already active, it remains to be seen how large their future market share will be, as mobile PV is likely to bring only a marginal increase in range, depending on location.
PV is a key component of the energy transition; in Switzerland alone it offers the potential for 67 terawatt-hours on roofs and facades, of which 3.65 gigawatts are installed today (as of 2021), whereas annual electricity consumption is at 58 terawatt-hours. At the moment, rapid expansion of PV is the greatest challenge. Once PV accounts for a larger share of the electricity mix, the key factors will be how the fluctuating energy yield is transported and stored, and how its use is controlled, whereby Switzerland is in an ideal position to solve this challenge using hydropower. PV is a mature technology that has a good ecological footprint, is widely accepted by the general public and can be rolled out on a large scale. PV does not only represent an opportunity for the energy transition though: It also opens up numerous possibilities for Swiss research and industry.
Even when Chinese PV cells are used, more than 50 percent of the added value remains in Switzerland if the partial manufacture of inverters and cables in Switzerland and installation work are taken into account. This value can be increased if products from Swiss system manufacturers with a production site in Europe are used. Switzerland makes a significant contribution to building-integrated PV worldwide as a location for research and production. Building integration is becoming increasingly important in other countries, thus offering key opportunities for Swiss firms, with their knowledge advantage. Processes and material development are relevant research fields for the purpose of increasing efficiency, reducing the cost of cells or replacing the silver used for conductors and contacts. Today, silver accounts for about 10 percent of a PV cell’s manufacturing cost and is only available in limited quantities. The solar industry already processes 15 percent of the silver mined today, so in order to grow, it has to directly compete with the electronics, telecommunications and electromobility industries, which also rely on this precious metal.
In Switzerland, a number of obstacles make it difficult to tap the full potential. There is currently no uniform, plannable, nationwide feed-in tariff here, which means that identical projects pay off differently, depending on their geographical location within Switzerland. The authorisation procedures are also regulated in a federalist manner, which further impedes widespread implementation.
One topic for the future is the recycling of used modules. Although most have not yet reached the end of their expected service life, which is 25–30 years, it is important to conduct research early, before the cells have to be disposed of on a large scale. In principle, PV modules can be recycled to a certain extent, but it is not yet economical to do so. There is some initial activity in Germany and Japan, but this is still very limited because the issue is not yet urgent. Switzerland should be getting involved in such activity, even though it does not represent an exclusive opportunity.
In order to reduce dependence on producers in the Far East, at least some of the cells and modules should be produced in Europe, and Swiss firms could play a major role here with regard to both conventional and building-integrated modules. This would not only ensure that know-how remains on this continent, but also that the technologies developed as a result of research could be applied more-or-less locally. It would also improve the PV cells’ eco-balance, compared to products manufactured in China. Such a vision is a great opportunity for the entire continent and one that Switzerland should also support.
Political authorities can take action at various levels to promote the expansion of PV capacity. It would be helpful to make solar power compulsory, not only for new buildings, but also when renovating existing buildings, as has been decided in the canton of Basel-Stadt. The feed-in tariffs should be unified and predictable nationwide, as the present electricity market model is unsuitable for efficient expansion of renewable energies. The same applies to the authorisation procedures, which should be simplified, accelerated and unified across the country, albeit without eliminating careful assessment. For large-scale systems, a shift in the support scheme towards a sliding market premium based on the international model could be a step in the right direction. Facade-mounted systems and alpine ground-mounted systems are particularly suitable means of increasing electricity production in winter. The National Council and the Council of States cleared the way for rapid expansion of such systems in their 2022 autumn session. Specifically, the construction of PV systems with a minimum annual production of 10 million kilowatt-hours and a winter yield of at least 500 kilowatt-hours is to be accelerated and simplified by the end of 2025, as per an emergency federal act. Despite this progress, further investment in research and development and in the transfer of technology to companies is needed, as is support for demonstration projects, in order to remain competitive internationally and to retain the possibility of European or local production.
