• Semiconductors generate free electrons through supplied light energy:

  1. electrons combine with boron atoms and form boundary layer upper silicon phosphorus layer has donated electrons (=donor) and is initially positively charged; lower silicon boron layer has accepted (=acceptor) and is negative

  2. light incidence excites and repels excess electrons in boron atoms electrons migrate to the positive upper layer -> lower layer has electron deficiency or wants to accept electrons

  3. electrons are conducted to the lower, now positive area Solar cells have metallic conductors at the top and bottom

• Current flow generated via the conductors is direct current is carried away/used via cables

In addition to the area and performance of the solar system, it is crucial that the consumption of the house is based on the weather forecast and time of day.

The OPENLY system controls all the washing machines and dishwashers in the house and runs them sequentially during the day. Ditto with charging the e-cars (if at home). The surplus electricity is stored in a recycling battery. (Dimensioning 50% of the average daily production)

The weather forecast is used to fill the heating storage tanks to cushion the increased demand on the following day.

• The silicon required in the manufacture of photovoltaic modules is extracted from quartz sand and refined in specialized plants

• After cleaning, the silicon is sawn into thin wafers. These are polished and cleaned to remove impurities. Wafers for monocrystalline solar cells are only a few micrometers thick.

• Solar cells are doped to maintain their conductivity. Elements such as phosphorus or boron are used in this process.

• Then they are arranged in a module frame and covered with protective glass or plastic.

• The silicon layer in the cells is less than half as thick as it was just a few years ago, and sawing the silicon produces less waste.

• Through technological advances and continuous research and development, the production of photovoltaic modules is becoming increasingly efficient and cost-effective, helping to establish solar power as a major renewable energy source worldwide. the manufacturing process of solar cells greatly improved.

• OPENLY Valley Widnau has installed the latest generation of PV modules with an output of 425kwP

per 2 m² solar module Trina Vertex S TSM-DE09R.08:

• incl. module, cabling, fasteners and inverter

• PV life expectancy is 20 years/for inverters 10 years

• Main components: silicon, aluminum, steel, copper, phosphorus, boron

• monocrystalline silicon cells have an efficiency of up to 22%.

• Module A1-3 Emissions for resource provision & production up to the factory gate: 604.62 kg CO₂

• Module C4 emissions for disposal at end-of-life: 24.42 kg CO₂

• Module D Recycling potential incl. loads for processing, material recycling: aluminum, steel, copper; thermal recycling in waste incineration plant: plastic and printed circuit board and landfill: glass, PV cell: - 66.84 kg CO₂

• Module D with electricity credit includes loads for reprocessing and credits for substitution of primary materials/fossil fuels for electricity production over 20 years: - 2092 kg CO₂.

• Photovoltaic modules do not use raw materials that are in short supply worldwide or cause problems in their procurement.

• The main materials used are silicon, which is obtained from sand, and aluminum. A small amount of silver is also present in solar cells.

• Solar cells are not toxic and do not constitute hazardous waste. However, similar to other electronic devices, they contain some materials that should not be released uncontrolled into the environment.

• This is particularly a small amount of lead, which is built into the electrical contacts. Traces of cadmium are also present in some solar cells. During operation, these substances are firmly bound and are not washed out, but proper disposal is crucial.

• The production of lead-free photovoltaic modules is possible, but somewhat more cost-intensive. For this reason, lead-free systems have not yet gained widespread acceptance on the market.

• However, the European Union is planning an Ecodesign Directive for photovoltaic modules in 2023, which is intended to promote environmentally friendly design and the use of resource-saving materials.

• Sustainability through green electricity - accelerated energy transition for climate protection

• high degree of energy self-sufficiency - low electricity costs, decentralized energy supply

• Durability - low maintenance

• mature technology

• expensive to buy

• fluctuating yield - naturally depending on the time of day, season and weather conditions

• CO₂ -calculation according to ÖKOBAUDAT, acc. to ISO 14067 & EN 15804+A2

• Gerbinet et al. (2019) 'Life Cycle Analysis (LCA) of photovoltaic panels: A review, Renewable and Sustainable Energy Reviews, Volume 38, 2014, Pages 747-753, ISSN 1364-0321, https://doi.org/10.1016/j.rser.2014.07.043.

• Kobler AG