Recently I read that Solar Power may be generated for 8-12cUS/kWh.

Does this make for a competative production price, given retail electricity costs?

Should environmental costs be factored in to current prices, as some suggest they must inevitably be, would it then be competative?

Should the lack of fissionable by-products be taken into consideration, given the current suite of Wars (on Terror, on Drugs, under the Rugs, etc)?

Last week, we showed you how everyday Danes profit from pioneering wind power. But there’s a challenge — how to store that power when the wind isn’t blowing. Denmark is searching for answers, including building Europe’s first “hydrogen neighborhood” — homes that are powered and heated with the help of hydrogen fuel cells. John Larson reports from Denmark. worldfocus.org

I am curious if the use of heat pipes are used to thermally heat a solar hot water tank, if so what material, wick type and working fluid are used?
When, I say heat pipes, I’m refering to specifically the near superconducting passive heat transport systems found here: http://en.wikipedia.org/wiki/Heat_pipe The reason I ask is that I’m trying to model the head transfer between the working fluid and water in the tank.