Geothermal energy has enormous potential for meeting the energy needs of low-carbon economies.  How much?  According to MIT, an "estimated that tapping just 2% of the potential resource from so-called enhanced geothermal systems between 3km and 10km below the surface of continental USA could supply more than 2,500 times the country's total annual energy use."

Problem is, thusfar it has often been quite expensive to access and involves expensive drilling projects.  Good news on the way however, as Guardian reports a new tool has been developed and tested by Potter Drilling.  The tool has managed to reach a depth of 1000 feet deep in the earth, which is a good first step.  The bulk of geothermal energy potential lies as much as 3-10km deep in the earths crust, so there is still some way to go.  But the technology is proving very promising and it is likely this depth may eventually be reached.  This would have a massive effect on lowering project costs and improving the potential for geothermal energy to be tapped worldwide.  Something to watch in the years ahead. 

Courtesy of Green Habitat Design, here's a quick primer on how geothermal works: