While some parts of the world enjoy relatively unimpeded sunshine, other parts tends to experience high speed winds. The construction of onshore and offshore wind power plants provide an excellent opportunity to exploit these winds to produce clean and sustainable energy. Out at sea, the wind is so much more forceful. Higher average offshore wind speeds can result in an energy yield of up to 70 per-cent more, than power generated by land based wind turbines - so it is no wonder that we will see an increasing number of offshore wind farms.
But, as well as growing in terms of number and rated power, offshore wind farms are being located farther from the coasts and the grid entry points. This means the impact of large-scale offshore wind power penetration may potentially affect the stability of the grid, particularly considering the intermit-tent nature of wind.
In addressing these challenges, ABB has developed a detailed design for an onshore and offshore HVDC (high-voltage direct current) system that can safely and reliably integrate large-scale wind power pro-duction, using its HVDC Light transmission technology.
It offers support to meet challenging grid access requirements and helps to improve power quality issues at the connection point. This technology provides superior controllability and quick power resto-ration during and after disturbances and caters for contingencies including blackouts. HVDC Light technology also supports weak grids with features like black-start capability, fine-tuning of AC voltage and reactive power, as well as the ability to energize wind power parks at zero or low wind conditions. Last but not least, this transmission system is ideal for stabilizing irregular electricity flows by quickly compensating for power fluctuations.
ABB has already commissioned three offshore wind HVDC installations, all placed in the North Sea, ca-pable of transmitting around 2,100 megawatts of wind power to consumers. HVDC for offshore wind has become an established and proven technology. It helps make wind power an attractive renewable resource also in densely populated regions or environmentally sensitive areas where onshore wind farms might not be an option.
In addition to the outstanding controllability, HVDC technology also offers the possibility of efficient transmission of large amounts of power with a minimum of losses, thereby enabling grid interconnec-tions over very long distances. By interconnecting grids, hydro power and other energy sources can be used to complement more intermittent renewables like wind and solar and will hence provide opportu-nities for more efficient use of our natural renewable energy resources.
ABB has continuously pushed the boundaries of HVDC Light Voltage Sourced Converter technology that was invented by ABB in the 1990's. The latest enhancement of ABB's HVDC Light has more than double the power capacity for the technology up to 3,000 megawatts (MW). System design enhancements also bring a step change in compactness, with a potential to deliver 350 percent more power per square meter of space used - an enormous benefit in terms of converter station footprint, be it on off-shore platforms or onshore installations. The latest advances, doubling power and distance capability, were made possible with the further development of semiconductor-based power electronic devices that provide greater control and make smaller HVDC systems also more economical.
