Comments on energy sources for the world's post-petroleum era

The author having just read the article: "Energy Sources for the World's Post-Petroleum Era" in the November 2003 edition of IEEE Systems Magazine would be interested to know what information sources were used when quoting costs, performance, and efficiencies for solar power systems. Also the quote from the German E-On. Being German and having run a solar power system for several years, the author disagrees with a lot of the statements.