Usage of a term depends on it's definition. So where is it?? In your post or somewhere?

There is such a term like Earth analog which is the synonym for Earth-like planet (I found it in Wikipedia and the first poster should try using it), there are no good specifications inside that specific article, although the round talk under "Attributes and Criteria" is quite similar to the above posters.

http://en.wikipedia.org/wiki/Earth_analog#Surface-water_and_hydrological_cycle
How about somebody define it then?

There is something a little bit more specific in:
http://en.wikipedia.org/wiki/Earth_Similarity_Index
- At least you can say for sure that KOI 736.01 has Earth Similarity Index (ESI) of 0.98 and Standard Primary Habitability (SPH) of 0.63.

So, anyone getting far enough with reading the article to reach the "..or to be more precise the smallest Stirling engine" part?

As the article says, there is no such battery yet, because it still needs an appropriate anode. So, the suitable words right now are still - would and could. If that was what you meant.

Everlasting is a lame use of words anyway, being overused nowadays by .. everyone(!). But if someone could say "This battery could last for a thousand years.", is cool. Now imagine Winston Churchill saying that.

Solar cells are potentially made from carbon :
graphene - http://www.alternative-energy-news.info/carbon-based-solar-cells/
or carbon nanotubes - http://www.bitsofscience.org/solar-cell-carbon-nano-energy-3418/
http://inhabitat.com/carbon-nanotubes-could-create-better-solar-cells/

The other technologies like wind turbines and those steaming solutions are just alternative green solutions to solar cells that are often cheaper. When the solar cells are going to continue to get cheaper like they are and no new alternative pops out, then they will probably be the prefferable choice of green energy.
http://www.guardian.co.uk/environment/2011/jun/20/solar-panel-price-drop
Their co-existence with new ways of storing electricity would make them even more practical.
New cheaper ways for making hydrogen:
http://www.gizmag.com/fukai-hydrogen-extraction-process/16674/
or carbon based supercapacitors?
http://www.sciencedaily.com/releases/2011/05/110512150731.htm
My point is, that there are actually new advancements in every horizon, which make this article a bit outdated.

AC:

WHAT?

1. Sahel is a part of the Sahara desert with probably the worst famine problem in the world. Part of the problem is that the land is being over used and then turns into desert.

-http://en.wikipedia.org/wiki/Sahel

2. Now, are we aware that Eurasia and Africa aren't one little island west of USA? The closest land route between China and Sahel would be something like 4500km and it would go over the hills, (other) deserts and through countries with not so friendly governments, bandits and areas with no roads. The sea transport would take months.

3. In EU the overproduced wheat (side effect of the EU's agricultural market stabilization measures) is being burnt because it would be too expensive to ship it to .. Sahel for example.

4. I am probably answering to a troll, again. I am not going to delete the post this time.