PROJECT TITLE :

Very long distance connection of gigawatt-size offshore wind farms: extra high-voltage AC versus high-voltage DC cost comparison

ABSTRACT:

This study presents a price comparison between commercially on the market high-voltage DC (HVDC) and extra high-voltage AC shore affiliation (±320 kV voltage supply converter and 420 kV–50 Hz single-core and 3-core cables), for a 1 GW offshore wind farm cluster, considering transmission distances up to four hundred km. The HVDC system could be a purpose-to-point connection whereas multiple AC intermediate compensating stations are envisaged for AC when needed. Capital prices are evaluated from recently awarded contracts, operating costs embody energy losses and missed revenues due to transmission system unavailability, each estimated using North Ocean wind production curves. Optimal AC intermediate compensation, if any, and reactive profiles are taken into consideration. Resultsshow that HVDC has lower transmission losses at distances in way over a hundred thirty km; but, due to the combined impact of lower AC capital price and unavailability, using three-core aluminium cables will be additional convenient up to 360 km distance.