share price, page-7

http://en.wikipedia.org/wiki/Geothermal_energy

"Drilling accounts for over half the costs, and exploration of deep resources entails significant risks. A typical well doublet (extraction and injection wells) in Nevada can support 4.5 megawatts (MW) and costs about $10 million to drill, with a 20% failure rate."

They'll have to update that cost.

"Estimates of the potential for electricity generation from geothermal energy vary six-fold, from .035to2TW depending on the scale of investments.[1] Upper estimates of geothermal resources assume enhanced geothermal wells as deep as 10 kilometres (6 mi), whereas existing geothermal wells are rarely more than 3 kilometres (2 mi) deep.[1] Wells of this depth are now common in the petroleum industry. The deepest research well in the world, the Kola superdeep borehole, is 12 kilometres (7 mi) deep.[26] This record has recently been imitated by commercial oil wells, such as Exxon's Z-12 well in the Chayvo field, Sakhalin.[27]"

12km deep.. Warren.. mate.. go on.. I dare you :-)