Geothermal Energy - Is It Being Underestimated For Long Time?

Some time back I came to know about the scientists at Pacific Northwest National Laboratory. They have developed techniques to tap the low temperature geothermal energy sources economically. I think this would also be useful for countries which are located far away from the earth’s tectonic plate boundaries.

PNNL scientists developed a liquid which rapidly expands and contracts. This is christened as a biphasic fluid as per its properties. The liquid when exposed to heat brought to the surface from water circulating in moderately hot rock at earth’s crust the thermal-cycling (the one seen in normal coal fired power plants) of the biphasic fluid will power a turbine to generate electricity.
Not only that. The scientists have also tried to increase its efficiency PNNL people have used specially constructed nanostructured metal organic material (MOHC) as heat carriers. People from MIT have estimated that if the technology developed by PNNL is commercially available it would lead contribute to 10% of USA’s energy demand.

Myth v. Fact - January

Sir,
i read that article of Myth Vs Fact. But what I am trying to ask, have you worked in this field and found any anomaly in the current technology taking the reference of this article?

As far as i can comprehend, they have only stated myth and facts while giving the possible (appropriate or not) reasons.

There is nothing wrong with current technology for geothermal energy harvesting. Wherever it is available near the surface it is a good option. As far as I can see in locations where the hot rock is too far below the surface (like in India) the cost of harvesting is currently too high.

To me one factor why geothermal energy is only advancing slowly, is the mindset that to gain energy from the earth's core, you would have to use mechanical processes. To be able to get the heat required for this, you would have to dig deep, which in turn means that costs are very high indeed.

We might need to look at carbon-based life, if we want to extract some form of energy from the warm, close to surface regions. Abandoned mineshafts might provide the ideal habitat for organisms that require heat and minerals, commonly found in the ground-water of such shafts.
(Since daylight is not avaiable, these organisms cannot rely on photosynthesis.)

These organisms can than be processed into bio-fuels. Processing algae into bio-fuel is pretty common nowerdays, however finding organisms that can live, and benefit from living in such an environment, and than be suitable for being processed into bio-fuel can be a challenge...

My message: "Geothermal energy is versatile, start thinking."

Thermodynamically it is most efficient to harvest heat as heat if possible. Growing biomass for later conversion is a costly process and leads to Carbon Dioxide generation, which adds to the problem. The fact remains that in India the hot rocks are too far below ground level for economic harvesting using existing technologies.

Yes, from a Thermodynamics point of view it is.
But using current technology, it is hardly possible to gain (mechanical) energy from the regions close the the surface. Abandoned mineshafts are normaly only used to dump waste in, eventhough they have alot of potential for geothermal energy.

The current tec. of geothermal energy is mearly suitable for India. For geothermal energy to be used there, the entire concept of it has to be changed from the ground up, that is in my opinion. Drilling is one problem, but pumping water down without causing geological instability is something else. Drilling technology can advance quickly (plasma drilling concepts). But there simply are only a limited amount of concepts for extracting geothermal energy, which means that scientists are only experimenting in places which are ideal for geothermal energy, therefore not alot of thought is spent for regions that are not ideal, but which do however have potential.

I must disagree with you on the cost of harvesting biomass.
Harvesting biomass can be done cheaply and the prices of bio-fuel can compete against those of fossil fuels.

I'm not an expert on this subject, but as far as i know some algae are even used to filter exaust fumes form factories and power plants, and are futher processed to bio-fuels.

The issue is biomass has low energy density in the raw state. Getting biomass to a state suitable for energy generation is not very cheap. On the other hand, certain algae generate electric power directly by photosynthesis. Some basic work is going on in this area. Far from being a practical proposition. The great advantage is that it consumes CO2 to produce electricity.
I am all for exploiting biomass for energy. Very long back I had interacted with Dr.AKN Reddy, the founder of ASTRA, IISc, Bangalore and a long time friend, in this area, though for biogas generation.