The author wrote followup article in which he estimates costs for a more reasonable system that is sized for winter production rather than annual storage:

A Potential Solution to the Problem of Storing Solar Energy – Don’t Store It.

http://euanmearns.com/a-potential-solution-to-the-problem-of...

As commenters here and on the blog suggest, this is a much more cost effective approach (although still prohibitively expensive in extreme latitudes).