Q & A
How does the electricity reach the land?
Gemini will be equipped with 2 export cables that will transport the 220Kv alternating current to land in Eemshaven. Both cables are some 120 kilometres long, have a diameter of 30cm and an aluminium core. They will arrive on land in Eemshaven where they will be connected to a transformer substation. Here, the voltage will be increased to 380 Kv. Via a cable to Oude Schild, the wind farm will be connected to the TenneT national grid.
For the cable route, the principle ‘bury and forget’ applies. The contractors will bury the cable at a guaranteed 2 metres below the seabed. The cable will always remain below the seabed, regardless of how the shifting seabed dunes move in the future. In some places, the cable will be buried some 12 metres below the seabed.
Who will purchase the electricity?
Most of the electricity produced by the Gemini Wind Park will be purchased by Delta, the energy company from Zeeland. This will make Delta the largest wind energy supplier in the Netherlands. The wind farm produces sufficient energy to provide four times the population of Zeeland with electricity. A small proportion will be purchased by HVC, one of the Gemini shareholders.
How long will the turbines last?
Gemini has licences to operate the wind farm for 20 years. After this period, the wind farm and everything that has been introduced onto the seabed must be removed. A bank security of €40 million has been made available for this. Economically, and if well-maintained, the wind farm can last much longer, especially if turbines are replaced with new turbines that may be even more efficient. To maintain the wind farm, an average 20 maintenance technicians will be based permanently at sea. Special maintenance vessels will transport them to the turbines. Lifts will take them to the nacelles containing the generators and gearboxes.
Why the name Gemini?
The Gemini Wind Park comprises 2 wind farms, each with 75 wind turbines. These are being constructed at two locations close together, which is where the name comes from (Gemini = twins). The official names of the locations are Buitengaats and Zee-energie. The total area covers 2 times 34 km², 68 km² in total.
Why is wind energy so important?
These days we are more aware than ever of the need for a better balance with nature, especially about how we handle our energy resources. Currently, 4.5% of our energy production is renewable. Considerable investments need to be made in renewable energy to achieve the cabinet objectives of 14% renewable energy by 2020. Wind energy is an efficient and cheap form of sustainable energy, certainly in the Netherlands, a country so often exposed to strong winds. There is a constant windspeed of force 5 or higher at the Gemini Wind Farm location. The Gemini turbines can continue rotating up to gale force 11; above this, they switch off automatically.
How long before the wind farm is ready?
Construction of the Gemini Wind Farm started in January 2015. The expectation is that the farm will be fully realised in July 2017.