Climate Glossary: ​​Photovoltaics

Photovoltaic systems (photovoltaic systems) produce electricity from sunlight. Sunlight is available for a long time and to a very large extent. This means that photovoltaic cells are one of the sources of renewable energy. Therefore, the government wants to greatly expand the scope of PV, and according to the government’s target, 11 TWh systems should be installed by 2030. It is still under discussion about where to install the PV systems. Floating photovoltaic systems on water bodies provide an innovative option.

A photovoltaic system consists of several modules, which in turn consist of interconnected solar cells. If the quality is good, the service life of the photovoltaic system is 25 to 30 years. Technically, photovoltaic systems will run longer if they aren’t exposed to the weather, but they lose a bit of their performance over time.

The photovoltaic system does not emit any greenhouse gases during operation, but the emissions are incurred during the production of the solar cells. In 2021, the production of solar cells will result in the emission of about 106 million tons of carbon dioxide worldwide, according to International Energy Agency figures. The bulk of emissions is due to the extraction of raw materials. More than 90% of the photovoltaic systems imported into the EU in June 2022 came from China, according to Eurostat data evaluated by the Bruegel think tank in Brussels. According to the International Energy Agency, the modules there are largely produced using coal-fired electricity, but photovoltaic systems from China only have to be in operation for four to eight months to offset the emissions produced during production.

In the past 10 years, China has invested more than $50 billion (about 49 billion euros) in photovoltaic power production, ten times as much as Europe has invested, according to the International Energy Agency. From 2009 to 2019, the manufacturing cost of photovoltaic systems decreased by 89 percent. This is also due to the fact that PV is well-suited for mass production, as energy expert Thomas Kinberger of Montanan University explained to Leoben in an interview with APA.

According to figures from the Ministry of the Environment (BMK), photovoltaics contributed about 6 percent to Austrian electricity generation in 2022. Newly installed photovoltaic power production broke the gigawatt mark for the first time in 2022: systems with a peak output of 1010 megawatts were installed. The cumulative total production has doubled to 3.8 GW since 2019.

According to the government program, by 2030, 100 percent of the national electricity balance should come from renewable energy sources. Therefore, annual electricity needs should be covered by renewables, with fluctuations offset by imports and exports. This requires an increase in renewables of about 27 TWh by 2030. Of this amount, 11 TWh will be covered by photovoltaic systems. To achieve the government’s target, around 1.2 gigawatts of photovoltaic power will need to be installed every year by 2030. Based on developments in recent years, experts believe that this target is achievable.

As it stands, these 11 terawatt-hours correspond to photovoltaic systems with an area of ​​about 92 square kilometers, roughly the size of Linz. Exactly what areas should be used for this causes a lot of debate. The technical potential for suitable roof areas in Austria is around 21.5 TWh, with open areas (a bit of arable land) around 32 TWh, Kinberger explained. The total annual electricity requirement is currently around 71 TWh, but it will increase in the future.

An innovative possibility where photovoltaic systems are used is water bodies. In these floating PV systems, the PV modules are attached to floating bodies made of plastic. These floating systems can reduce conflicts over land use, the Austrian Photovoltaic Technology Platform writes in a fact sheet. At the same time, he notes, there are many advantages over traditional photovoltaic systems. For example, this results in less evaporation and less algae formation. In addition, floating photovoltaic systems can prevent wind erosion and produce more electricity through the cooling effect of water.

However, floating PV systems cost more than conventional PV systems due to installation and maintenance work, among other things. Its performance and durability can be affected by algae or similar growths, bird droppings, and mechanical drafts. Likewise, the potential impacts on the water environment have not yet been fully investigated, the photovoltaic technology platform writes.

Johannes Schmidt from the Institute for Sustainable Economic Development at the University of Natural Resources and Life Sciences Vienna (BOKU) confirmed these advantages and disadvantages of floating PV systems to APA. For Austria, he does not see much potential in this innovation as a contribution to the energy transition: “In my opinion, the economic potential – except for special cases – is low because the costs of alternative solutions are much lower.”

Daniel Hubmann of the International Institute for Applied Systems Analysis (IIASA) was also critical, saying: “There may be some water areas in Austria that are technically suitable for floating photovoltaic power. BUT: Federal states and municipalities are currently blocking the expansion of wind power.” There is no need for an umbrella. Photovoltaic in newly built car parks, not to mention mandatory retrofitting in existing car parks. Compared to this potential, floating PV is just a drop in an increasingly hot stone.”

So far, floating PV systems have been used and scaled up mainly in Asia. These are now also used in Europe. The largest floating photovoltaic system in Central Europe is located in Grafenwerth, Lower Austria. A floating photovoltaic system has also been installed south of Graz in Styria. Studies cited by the PV Technology Platform estimate the global potential for floating PV systems at 400 to 1,000 GW – combined with hydropower at 4,400 to 5,700 GW.