NordLink flows 1400 MW. Wholesale electricity in Germany is roughly $105.
365x24x(1400x.07)x105 = $90 million per year. Adds up to the cost of the total project every 17-22 years. Over 20 years it's $1.8 million per km. If the superconductor is 20 kg/m (2.4" or 6.2 cm width, huge), that's $90 per kilogram.
10x the cost of copper.