580
'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.
I work with statistics and joined a wind power forecast project, so I have been reading papers on wind power generation for the past month. There's other more complex formulas that the one shared on the link, but that was the first I found not pay walled.