The story of Potter Drilling, new geothermal drilling technology for EGS
Alexander Richter
10 Apr 2009
In an article on Potter Drilling it is described how the company "drills not with hard-as-diamonds bits but with water—extremely hot water. (More on that in a bit.) The goal is to radically cut the cost of EGS to spread the technology..."
Having come across this excellent article about the background of Potter Drilling, I thought I should briefly provide some points of the article and a link to it. “Drill, baby, drill …”
Potter Drilling a short description from the company’s website: “The company’s mission is to commercialize drilling technology that will lower the cost of developing Engineered Geothermal Systems (EGS). EGS has enormous potential to provide renewable baseload energy that is clean, secure, and universally available.
Potter Drilling was founded in 2004 by father-and-son team Bob and Jared Potter to develop and commercialize innovative drilling technology. Bob Potter, co-creator of Potter Drilling’s technology, was one of the inventors of the Hot Dry Rock (or EGS) concept while working at the Los Alamos National Laboratory in the 1970s.”
“Potter drills not with hard-as-diamonds bits but with water—extremely hot water. (More on that in a bit.) The goal is to radically cut the cost of EGS to spread the technology to regions that rely too much on coal for generating electricity but are not suited for solar, wind and other renewable energy generation.”
“Drilling as deep as six miles below the earth’s surface is incredibly expensive, presenting a host of obstacles to overcome. Even conventional geothermal developers spend millions of dollars to just drill test wells. But EGS rigs must penetrate miles of hard rock that slows drilling to a crawl. And a broken drill bit 30,000 feet underground can force the abandonment of a $10 million well.”
The article then continues to describe a screening on a drilling demonstration by Potter. “Salad plate-sized analog gauges line either side of the seven-foot-tall U-shaped device. Suspended in the center is a silver container about the size of small beer keg connected to various tubes and valves.
… As chemical reactants begin to heat up the water supply, a battered, second-hand flat-screen monitor attached to the apparatus shows the temperature rising—200C, 400C, 600C. When it hits 800C (lead melts at 327C), the hot water is forced through nozzle. As the sound of the machinery intensifies, the jets of water begin to fracture the surface of the granite, dislodging tiny particles of the rock.”
“By dispensing with breakable drill bits and other components that risk failing at great depths, the Potters hope to jump-start EGS by slashing both the cost and the time it takes to drill a well, which can account for more than half of a geothermal power plant’s price tag. That drilling risk has proven a deterrent to investors who don’t want to take the chance of literally pouring millions of dollars down a dry hole.
“We think we can cut the cost by 50 percent,” says Jared Potter. That has sparked interest from such leading EGS companies as Geodynamics of Australia.”
To read the whole article, which I think is indeed worth it, use the link provided below.
Source: Todd Woody for grist.org
