Wind power plants produce two-thirds of their annual electricity yield in the winter months, when output from solar and hydroelectric power is lower. This includes wind farms as well as individual wind power plants. So wind energy is the ideal complement to other renewable energies.
In 2023, ewz’s wind farms and wind investments throughout Europe produced around one terawatt hour (TWh) of wind energy for the first time. This equates to the volume of energy that ewz produces in its own hydroelectric power plants in the Grisons and on the Limmat River. Our goal is to increase power generation from wind power to up to 2.5 TWh by 2050. Wind power is to be expanded both in Switzerland and internationally.
Canton of Zurich
ewz has joined forces with Elektrizitätswerken des Kantons Zürich (EKZ) and Stadtwerk Winterthur to form the Zürich Wind cooperation. The aim of the cooperation is to develop, finance, build and operate joint wind projects.
For more information, visit: zuerichwind.ch (in German)
Canton of Vaud
In the canton of Vaud, ewz is planning the Mollendruz (in German) wind farm. It is being built in collaboration with the municipalities of Juriens, Mont-la-Ville, La Praz, Vaulion and the city of Yverdon-les-Bain with a common goal of promoting local, sustainable and environmentally friendly renewable energy. In cooperation with Romande Energie, ewz also intends to build the Provence wind farm south of the Val de Travers.
Further information about wind energy can be found in powernewz, ewz’s energy magazine.
Development, construction and operation of wind farms
ewz (Deutschland) GmbH, a company of the Zurich Municipal Electric Utility, has 14 wind farms and 6 wind investments in Germany, France, Norway and Sweden. The more than 125 wind turbines produce around 1 TWh of electricity per year, which corresponds to around 20% of ewz’s total electricity production.
ewz favours investment in locations that clearly meet requirements in terms of efficiency, climate as well as environmental impact and acceptance of the investment.
You can find the current Annual Report of ewz (Deutschland) GmbH here (in German).
A wind power plant covers the same area as a single-family home and generates electricity for about 10,000 people for 30 years. This is equivalent to the amount of electricity needed to power 5,000 electric cars for 30 years, each travelling 15,000 km (source: suisseéole in German)
According to a current potential study by the federal government, 3,000 wind power plants could compensate for the electricity shortfall in winter and the phase-out of nuclear power. Even 1,000 wind turbines would be enough to fill the winter electricity gap with additional wind energy during the darker months of the year. You can find more information in the the federal government’s press releases (in German) and in the report from the perspective of Suisse Eole (in German).
The generation of electricity from renewable energies is supported by a federal funding programme. In addition to wind power, the programme supports solar energy, biomass, hydroelectric power and geothermal energy. You can find an overview of the funding programmes here (in German).
Wind of less than 10 km/h is not enough to start a wind power plant and have the blades operate the turbine. Conversely, if the wind is too strong the wind power plant will come to a standstill. This safety function is intended to prevent the threat of damage to the systems, minimise wear and tear, and ensure there is no risk to public safety. So a wind turbine rotates at different speeds during its operating time, depending on the wind force.
This variable frequency means that a wind power plant produces just as much electricity in a year as if it had rotated at maximum capacity 20 to 25% of the time. This is referred to as the utilisation factor or utilisation rate.
Even in good wind conditions, wind turbines do not always spin. One possible reason for this is negative electricity prices, which can make power generation uneconomical at times. Negative electricity prices can arise when more electricity is produced than can be consumed at the same time. In this case, it’s worth temporarily switching off the systems.
In addition to a lack of wind or negative electricity prices, safety functions and necessary maintenance work can also cause the plant to temporarily shut down. Regular maintenance ensures that the wind power plant can be kept in operational condition.
Yes, wind power plants do cause noise. However, any potential noise pollution is limited by legal requirements. The federal Noise Abatement Ordinance, for example, stipulates that plants must be quieter at night than during the day. The relevant measure for noise emissions is the decibel rating from the nearest inhabited house. These values are usually very low, around 25 dB. As a comparison, a discussion in a normal conversational tone corresponds to a volume of around 60 dB.
The performance, safety and weather resistance of wind power plants have been continuously improving for many years. Wind turbines also benefit from advances in many related technologies, such as vehicles, computers and construction. When a wind turbine is generating electricity up to a wind speed of about 90–100 km/h, it is constantly looking for the best wind exposure (facing the wind). At wind speeds above its operating range, during violent storms, it does exactly the opposite. The wind turbine then moves into what is known as the flag position, in which it automatically positions itself parallel to the wind to minimise resistance.
There’s no denying that wind power plants influence and change the landscape. This also applies to dams and their reservoirs, high-voltage power lines and other human-made structures.
Overall and from a legal point of view, damage to the landscape may be justified if there are overriding public interests. Boosting economic activities based on sustainable development may be one such justifiable interest. The development of renewable energy sources is one of the purposes for which certain impairment of the landscape is considered acceptable.
Yes, birds die from wind power plants. However, it is important to consider the orders of magnitude. Due to the difficulty of counting (for example, because wild animals carry birds away), the figures vary. The Swiss Ornithological Institute (in German) in Sempach lists around 20 per plant per year. In total, around 870 birds die from wind turbines every year.
By way of comparison, in Switzerland, around 36 million birds die every year as a result of domestic cats, glass facades and traffic (source in German).
A study at the Gotthard wind farm shows that in 36 months 1,700,000 migratory birds crossed the wind farm, 99.99% were unaffected by the wind turbines (source in German).
The greatest threat to birds is human activity in general, in particular the impacts of intensive agriculture and transport routes on habitat loss and climate change. According to Suisse Eole, 75% of breeding birds are threatened by climate change. So the use of wind energy as a substitute for fossil fuels also helps to protect birds and bats.
In principle, lightning can strike wind power plants, and ice can form in winter. However, there are technical measures that prevent possible damage.
- Lightning
Wind power plants are tall and occupy elevated open spaces, so there is a risk of lightning strike during every thunderstorm. However, all wind power plants are equipped with lightning rods. The rotor blades contain cables that conduct the lightning via earthing cables. These measures serve primarily to prevent damage to the rotor blades in the event of a lightning strike. - Ice
In rare cases, ice can form on the rotor blades of wind turbines in winter, under certain temperature and humidity conditions. This can affect production, but it can also pose a risk to the public if ice comes loose. To minimise this risk, wind turbines are equipped with the latest technology in this field, including heated rotor blades and automatic shutdown. An automated system detects ice on the rotor blades and temporarily shuts down the wind turbine to activate the heating system for the rotor blades. There is no such thing as zero risk in any area, so there is a designated safety zone around wind turbines in winter to reduce residual risk.
