Technology Review has an article on improving Low Temperature Geothermal Power generation using a "superior type of heat-extracting fluid " - Cheaper Geothermal.

Researchers at Pacific Northwest National Laboratory in Richland, WA, say they've developed a superior type of heat-extracting fluid that could dramatically improve the economics of producing renewable power from low-temperature geothermal resources.

Lab fellow Pete McGrail says the liquid is used to absorb the heat from hot water that's been pumped from underground into a geothermal plant's heat exchanger. The liquid can potentially boost the rate of heat capture by 20 to 30 percent. Researchers engineered proprietary nanomaterials made up of metals linked by organic molecules. They found that adding the nanomaterials to a fluid such as hexane or pentane significantly enhanced the heat-trapping properties of the liquid.

"The hope here is that by improving the efficiency as much as we think we can, a project can become economic at much shallower depths," says McGrail. "You'd be able to deploy in what would now be considered marginal or uneconomic areas."

There's no shortage of geothermal energy under our feet. Drill deep enough and the heat is there. An MIT-led study from 2006 concluded that geothermal power systems have the potential to supply 100 gigawatts of power to the United States by 2050, but only if new drilling and rock-fracturing technologies and advanced plant designs emerge that could lower development costs.

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Improved technologies are required because most economical geothermal plants today generate electricity by using steam or hot water directly from naturally formed high-temperature reservoirs, such as the Geysers field in California. The wells are relatively shallow, the water is 360 degrees Fahrenheit or hotter, and the rock is porous enough to sufficiently circulate water. Tapping geothermal resources in less-ideal locations requires drilling deeper and forcing fractures in rock, both of which add immense cost. It also means making the most of lower-temperature heat resources, which is accomplished using binary-cycle plants that extract and repurpose the heat from underground hot water rather than using the hot water directly to spin a turbine.

In these plants, water pumped into an injection well absorbs heat from hot rock and is pumped back up through a separate extraction well at temperatures ranging from 150 degrees Fahrenheit to 300 degrees Fahrenheit. The hot water is then passed through a heat exchanger, along with a fluid with a low boiling point. This fluid, which flows in its own closed loop within the plant, absorbs the heat from the water and flashes into vapor under high pressure. The vapor passes through a turbine, generating power, and is then condensed and recycled back through the loop.

McGrail and his research team stumbled on a way to boost the energy-conversion rate as the two loops pass through a heat exchanger. Initially, they had developed proprietary materials for another project to improve the capture of carbon dioxide emitted from a fossil-fuel plant. They realized that the materials had remarkable thermodynamic qualities when added to an organic fluid. The new fluid has the potential to capture up to 30 percent more heat from a closed water loop, and, because of its rapid expansion and contraction capabilities, it can achieve higher pressures for driving the turbine.

"It's one of those moments in the lab where you look at the data and say, 'Wow!'" says McGrail. His group has received a $1.2 million grant from the Department of Energy's geothermal technologies program to build a benchtop prototype that shows the properties of the fluid in action.

The ABC has a report on plans to power north-west Queensland with geothermal power (presumably low temperature geothermal using hot water from the great artesian basin) - Geothermal firm in bid to build regional powerhouse.

A Brisbane-based company says it could supply geothermal power to all of north-west Queensland. Clean Energy Australasia wants to build a $50 million geothermal power station near Longreach. But it has now also revealed plans to build a pilot geothermal project near BHP's Cannington mine at McKinlay, south of Cloncurry.

The company's Joe Reichman says the Mount Isa region needs about 500 megawatts of power a year and geothermal resources could easily provide that. "It'll change the region into a powerhouse," he said.

Mr Reichman says the company has applied for federal and state government grants and has support from the major mining companies in the region. If the projects proceed they would be the first geothermal power plants in Australia.

Energy Daily reports on a project generating power using hot water from an oil well - Oil well hot water used to make power.

The U.S. Office of Fossil Energy has announced the first successful generation of electricity using geothermal technology from a producing oil well.

"This project is unique in its production of onsite renewable power and has the potential to increase the productivity and longevity of existing U.S. oil fields," Acting Assistant Secretary for Fossil Energy James Slutz said.

The 12-month test began in September at a Rocky Mountain Oilfield Testing Center site north of Casper, Wyo. Officials said the power system being used is a commercial standard design Ormat Organic Rankine Cycle power plant. The binary power unit uses hot water from a producing oil well as the heating fluid for a heat exchanger.

In the heat exchanger a secondary working fluid -- an organic fluid with a low boiling point -- is vaporized. That vapor is used to spin a turbine coupled with a generator to produce electricity. Output is connected to the field electrical system to power production equipment, and the produced energy is metered and monitored for both reliability and quality.

Officials said the power plant has been producing 150 to 250 gross kilowatts of power since it was first started.