Eleven offshore grid connection systems with a joint capacity of 6,232 megawatts (MW) for offshore wind energy transmission from sea to land have now been connected to the power grid by transmission system operator TenneT. “With this, TenneT has now almost entirely achieved the federal government’s expansion goal of having 6,500 megawatts of offshore wind capacity by 2020. Already this year, TenneT will exceed this goal since the completion of BorWin3 in the course of 2019 will put a total of 7,132 megawatts of transmission capacity into operation in the North Sea alone,” said TenneT Managing Director Wilfried Breuer. By the end of 2023, another connection system will follow in the form of DolWin6, which will bring the available transmission capacity in the North Sea up to 8,032 MW.
The wind energy transmitted from the North Sea by TenneT amounted to 16.75 terawatt hours (TWh)*) in 2018 – a new record. This would be enough, for example, to cover the annual consumption of more than five million German households. The result in 2018 exceeded the previous year's value (15.97 TWh) by 4.9 percent. Measured against the total wind output of Germany (106.45 TWh, offshore and onshore counted together)*), the North Sea wind contribution achieved a healthy share of 15.7 percent in 2017.
“It was foreseeable that the increase in the transmitted quantity of wind energy from sea to land in 2018 would be less pronounced than in previous years,” said Wilfried Breuer, “making it all the more important to further accelerate the grid expansion on land in order to have the grid capacities on land needed to transport the electricity to the consumption-heavy regions of western and southern Germany as soon as possible.”
In parallel with this, TenneT is developing and participating in numerous innovative approaches and projects involving smart future technologies, digitalization of the electricity grid, increasing of its flexibility and advancing the coupling of the different sectors. “We are aiming at planning security and greater cost efficiency,” says Breuer. One current innovative approach in the offshore area is the planned 66 kV technology that will be used for connecting the offshore wind farms to the future TenneT connections of DolWin5 and BorWin5. This technology can reduce investment cost and operational expenses by millions since the offshore transformer platforms of the wind farms are no longer needed and significantly less cable is required for connecting the individual wind turbine systems.
The current maximum infeed performance of offshore wind farms in the North Sea reached 4,773 MW on 15 December 2018. The capacity expansion for offshore wind farms in the North Sea was at 5,307 MW on 31 December 2018. The wind turbines in the Baltic Sea (not within the TenneT grid area) generated 2.35 terawatt hours*) in 2018, which means Germany’s total offshore yield amounted to 19.1 terawatt hours*). With an additional 87.35 terawatt hours*) of generated onshore wind energy, the total yield is thus 106.45 terawatt hours*).
*) Financially subsidised electricity in accordance with the German Renewable Energy Act (EEG), without other direct marketing; for 2018, as the preliminary actual value. The volumes of energy produced onshore and in the Baltic Sea for the months of November and December 2018 are incorporated as preliminary estimated values.