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'Windmill': China tests world’s first megawatt-level airship to capture high winds
(interestingengineering.com)
This is a most excellent place for technology news and articles.
Oh sorry, I think I was responding to someone else. As for cable weight, I was playing around with this calculator and for a pure copper wire less than 3mm thick and 10km long, you only need to overcome 300kg in weight.
If you use the standard 20mm wide cables, then yes weight becomes a huge problem. But then maybe you use more balloons, or just secretly hook it over a few satellites when no one's looking