Geothermal energy developers plan to pump 91 million litres of water into the side of a dormant volcano this summer to demonstrate new technology they hope will give a boost to green energy.
They hope the water comes back to the surface fast enough and hot enough to create cheap, clean electricity that is not dependent on sunny skies or stiff breezes.
They also want to see if the water injected into the volcano in the western US state of Oregon will resurface without shaking the earth and rattling the nerves of nearby residents.
Renewable energy has been held back by cheap natural gas, weak demand for power and waning political concern over global warming. Efforts to use the Earth's heat to generate power, known as geothermal energy, have been further hampered by technical problems and worries that tapping it can cause earthquakes.
Even so, the US government, Google and other investors are interested enough to bet US$43 million (Dh158m) on the Oregon project. They are helping AltaRock Energy of Washington state and Davenport Newberry Holdings of Connecticut to demonstrate whether the next level in geothermal power development can work on the flanks of Newberry Volcano.
"We know the heat is there," said Susan Petty, president of AltaRock. "The big issue is can we circulate enough water through the system to make it economic."
The heat in the Earth's crust has been used to generate power for more than a century. Engineers gather hot water or steam that bubbles near the surface and use it to spin a turbine that creates electricity. Most of those areas have been exploited. The new frontier is places with hot rocks, but no cracks in the rocks or water to deliver the steam. To tap that heat - and grow geothermal energy from a tiny niche into an important source of green energy - engineers are working on a new technology called Enhanced Geothermal Systems (EGS).