Quoted numbers or not: not necessarily everyone is correct

Comments on Dylan McConnell "How much does wind energy cost? Debunking the myths", 23/06/2015 

While two people have quite different figures, it is unclear which one is more reliable and accurate after reading this article. It seems to me this article is not without its own shortcomings. For example, are all the quoted favourable figures really all reliable and accurate in the first Place?

I must however confess that I have not read the other piece to which this article is debating. But it may be reasonably expected that piece should also contain some quoted figures as opposed all figures coming from that author alone.