Hot dry rock geothermal energy as a separate state from that of the continuum of permeable rock—just as one would consider a completely closed faucet as distinct from one that is open to any degree, whether the flow be a trickle or a flood. In the same way, HDR technology should be regarded as totally distinct from EGS. A definitive book on HDR development, including a full account of the experiments at Fenton Hill, was published by Springer-Verlag in April 2012. Hot dry rock geothermal energy Hot dry rock (HDR) is an abundant source of geothermal energy available for use. A vast store of thermal
Echoes from the Underground dedicated to troops overseas, but as the song developed, he shifted it to more personal themes, and instead wrote "A Song for Someone" for the troops overseas instead. All songs written by Matt Scannell, except where noted. Echoes from the Underground Echoes from the Underground is the sixth studio album from the band Vertical Horizon, released on October 8, 2013. "Broken Over You" was released as the lead single. Rush drummer Neil Peart played the drums on two songs on the album, including "Instamatic". After the band's 2009 album, "Burning the Days", band co-founder Keith Kane left the band shortly