This article caught my eye yesterday and sent my mind racing. Though the headline “Project to Pour Water into Volcano to Make Power” seems too dumbed down and makes me wonder about the intelligence of the Yahoo news editors or their underestimating the intelligence of their consumers.
There is some beautiful irony if the oil industry’s investment in advanced drilling technology is adopted by the geothermal industry, leading to the eventual drastic decline in fossil fuel use.
The geothermal project in the article correctly identified the concept of using underground heat to turn water into steam, which turns turbines to create electricity. But their method as described appears a bit ham-fisted, even to this layman, and ignores the great potential for the concept. (Maybe the defenders of the energy status quo pulled some strings behind the scenes to direct funding only to the project that seems inefficient and likely to fail.)
Here’s the general idea:
Geothermal energy developers plan to pump 24 million gallons of water into the side of a dormant volcano in Central Oregon this summer to demonstrate new technology they hope will give a boost to a green energy sector that has yet to live up to its promise.
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.
“To build geothermal in a big way beyond where it is now requires new technology, and that is where EGS comes in,” said Steve Hickman, a research geophysicist with the U.S. Geological Survey in Menlo Park, Calif.
Wells are drilled deep into the rock and water is pumped in, creating tiny fractures in the rock, a process known as hydroshearing.
Cold water is pumped down production wells into the reservoir, and the steam is drawn out.
Hydroshearing is similar to the process known as hydraulic fracturing, used to free natural gas from shale formations. But fracking uses chemical-laden fluids, and creates huge fractures. Pumping fracking wastewater deep underground for disposal likely led to recent earthquakes in Arkansas and Ohio.
Fears persist that cracking rock deep underground through hydroshearing can also lead to damaging quakes. EGS has other problems. It is hard to create a reservoir big enough to run a commercial power plant.
I have a couple of issues with this. Look at the diagram.
It looks like they are just dumping water underground where it is hot and hoping the steam runs back up their pipe.
A second concern is the hydroshearing. Couldn’t they find a way to get the water down to the hot rocks without potentially disturbing the geology down there? I can.
Here’s a better way (and please, engineers out there, tell me how I’m wrong). Use that advanced oil drilling technology to drill down as close as you can without hitting the magma. Remove the drill and replace it with a hollow cylinder made of whatever metal you can find that conducts heat the best. Send water down this metal tube and it will all be steam before it hits the bottom. The electricity-generating turbines could be at the top of the tube. It might be possible to construct several turbines within the tube itself.
Now, I do like how they reuse the water from the generated steam. In the age of the multifunctional machine (think smartphones), I’d take it a step further and address another important resource scarcity: potable water.
How about we use seawater down there? When the turbines are done with the steam it can be condensed into drinkable water. I’m sure there is a design solution for the leftover “salt” that would accumulate at the bottom of the tube. There you have it: a plant that would take saltwater and produce electricity and drinking water.
OK, wiseguys, tell me how this wouldn’t work.