FOR years, those looking to generate electricity without using fossil fuels have dreamed of tapping the virtually unlimited heat source that lies 8 kilometres or more beneath Earth’s surface. Prior efforts have been stymied because getting to that heat entails drilling into rock that is too hard for conventional techniques. Now, one tantalising possibility involves repurposing an existing technology to tap into this source and produce electricity at a lower cost than any existing form of power generation.
This isn’t, however, simply a matter of economics. Even if all nations were to meet the pledges that were made under the Paris Agreement on climate change, temperatures …
