ReNew Economy has a post on efforts by AltaRock to reduce the cost of enhanced geothermal power generation by shifting to a single well model - Geothermal plant cost potentially cut by 50%.

Geothermal developers from AltaRock Energy, a Washington state-based company, have been working on creating geothermal reservoirs with their own technology. They have recently made three such reservoirs from a single well, which means there is a greater chance a commercial geothermal plant can be built because with more reservoirs there is greater flow and energy output for each well. With human-made reservoirs expanding the energy output, the overall cost of constructing a geothermal plant could be reduced by 50 per cent.

“The purpose of the Newberry EGS project is to demonstrate AltaRock’s tne technology designed to lower the cost of EGS, and thus allow economic extraction of heat from the earth in locations where high temperatures can be reached by conventional drilling techniques,” said Susan Petty, founder and president of AltaRock. (Source: Fort Mill Times)

These reservoirs are also called stimulated zones or enhanced geothermal systems, and located at the Newberry Enhanced Geothermal System (EGS) Demonstration site, which is near an ancient volcano in Oregon. They are created by injecting cold water into hot, low permeability rock to amplify fractures there, which then allows the surface hot water to leak out and fill the human-made reservoirs. (The Department of Energy has contributed over $20 million to their research.)

The potential costs savings results from the ability to create multiple hot water reservoirs from one well or single site. Alta Rock has made Thermally Degradable Zonal Isolation Materials (TZIM) to help create these multiple zones. A biodegradable polymer was used at the Newberry site in a process that was implemented several times. It is possible to do more than three stimulation rounds at one site for reservoir creation.

The Boston Globe has an article on an enhanced geothermal power project in Oregon - Project to pour water into volcano to make power.

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.

They hope the water comes back to the surface fast enough and hot enough to create cheap, clean electricity that isn’t dependent on sunny skies or stiff breezes — 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 federal government, Google and other investors are interested enough to bet $43 million on the Oregon project. They are helping AltaRock Energy, Inc. of Seattle and Davenport Newberry Holdings LLC of Stamford, Conn., demonstrate whether the next level in geothermal power development can work on the flanks of Newberrry Volcano, located about 20 miles south of Bend, Ore.

“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.’’

DELAYED geothermal projects could make it across the line this year as two SA-focused companies move further toward producing power, the industry association says. Geothermal company Geodynamics plans to drill its Habanero-4 well in the first financial quarter, taking it toward producing power to Innamincka.

Australian Geothermal Energy Association chief executive Susan Jeanes said "this is the year the industry can prove itself"'. She said the Geodynamics project, that suffered a major setback with a well blowout at Habanero 3 well in 2009, would also work toward fracturing rocks to achieve circulation of super hot water for its 1MW plant.

SA geothermal company Petratherm has drilled a deep well at its Paralana project north of the Flinders Ranges and completed a successful fracture. ...

Ms Jeanes was upbeat about the industry saying if the drilling work was successful this year it could help lead the whole sector forward. "We expect, that given (Geodynamics) successfully proved the concept with Habanero one and three that they will be successful with Habanero one and four because they are drilling into the same geological structure," she said. "That success at Innamincka will provide a huge boost of confidence in the sector, then the sector hopes that will be followed by a successful well at Paralana."

Petratherm managing director Terry Kallis said plans to begin drilling on a second deep well in the Paralana project were still on track for later this year despite TRUenergy's exit. "We haven't changed our plans. we're still on track to look to drill later this year," Mr Kallis said.

The New York Times has an article on slow drilling progress and fear-mongering about earthquakes that are slowing progress of a geothermal power experiment in California - Drilling Ordeals Said to Delay Geothermal Project.

The Obama administration’s first major test of geothermal energy as a significant alternative to fossil fuels has fallen seriously behind schedule, several federal scientists said this week, even as the project is under review because of the earthquakes it could generate in Northern California.

Intended to extract heat from hot bedrock, the project has been delayed because the bit on a giant rig, meant to drill more than two miles underground, has struggled to pierce surface rock formations, the scientists said.

The bit has snapped off at least once and become repeatedly fouled in a shallow formation called cap rock, and the drillers have twice been forced to pull it out and essentially start the hole over again.

Late last year, the project, undertaken by a start-up company called AltaRock Energy, received $6.25 million in financing from the Energy Department, in hopes that it would be the first of dozens of projects to produce renewable energy by fracturing rock at the bottom of a deep hole and then circulating water through the cracks to generate steam.

But last month, after an article in The New York Times raised questions on whether AltaRock had been forthcoming about earthquakes generated by a similar project in Basel, Switzerland, the Energy Department and the Bureau of Land Management informed the company that it would not be allowed to fracture rock until the department completed a new review of whether the project would be safe. The company was allowed to keep drilling, however, down toward the depth at which it would begin the fracturing.

The scientists who told of delays in the project spoke only on the condition that they not be identified, in order to preserve their access to company progress reports. The scientists said that after nearly two months of the highly expensive drilling, the rig had reached depths of less than 4,000 feet. The original schedule called for it to reach a final depth of 12,000 feet, or 2.3 miles, after no more than 50 days of drilling, according to company officials.

The problems are particularly surprising given that the drilling essentially started at 3,200 feet, at the bottom of an older hole at the site, north of San Francisco at a place called the Geysers.

The company has also raised some $30 million in venture capital. Among AltaRock’s high-profile investors are Google and the investment firms Khosla Ventures and Kleiner Perkins Caufield & Byers.

Advocates for the technique, known as an “enhanced geothermal system,” say it could eventually generate vast amounts of energy and reduce America’s dependence on fossil fuels. But the latest delays come as AltaRock awaits word on whether the federal government will allow the fracturing of rock at all.

The fracturing would be virtually guaranteed to induce earthquakes, which the company has said would be so small as to be nearly imperceptible but which local residents and some scientists fear could be larger. The project is in one of the world’s most seismically active areas.

Although the Basel earthquakes caused only minor structural damage, they frightened many in the city and led to the shutdown of the project there. The Energy Department review, likely to be released in the next few weeks, is expected to compare the Basel and California projects and determine whether AltaRock’s effort is safe.