Geothermal? Better in some states?
Geothermal? Better in some states?
(OP)
This made me wonder:
h ttp://www. energycent ral.com/ce nters/news /daily/art icle.cfm?a id=8222873
Geothermal energy has been tried in many places and seems to work well only in volcanic areas like Iceland and such.
Is there a difference between states in the US with regard to thermal energy? How do you judge the chances to make this work?
h
Geothermal energy has been tried in many places and seems to work well only in volcanic areas like Iceland and such.
Is there a difference between states in the US with regard to thermal energy? How do you judge the chances to make this work?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...






RE: Geothermal? Better in some states?
http://www.energy.ca.gov/geothermal/overview.html
http://www.energy.ca.gov/geothermal/
h
On a recent road trip to go shooting. Our family saw a bunch of steam rising from a part of the Nevada desert next to the highway. We pulled over to investigate. There were ditches filled with 200F water with signs warning of fatal temperatures. It was next to a plant of some sort. Don't know what the plant was using doing. But the geothermal waste was impressive.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Geothermal? Better in some states?
In the areas around where they have found the geothermal heat source in Nevada, water is even more scarce and there are no large communities from which they can take advantage of treated wastewater without having to pump it hundreds of miles. At some point the laws of diminishing returns will kick in.
RE: Geothermal? Better in some states?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Geothermal? Better in some states?
RE: Geothermal? Better in some states?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Geothermal? Better in some states?
What jraef is saying is that as you draw off steam from under ground to run through your turbine, there is very little water comming into the steam field to replace what you take away. Hence, grandiose water reinjection schemes that suppliment the natural water inflows. The problem is not in the condensing end of the turbine it is in the "boiler" feed water supply.
Interesting that have used wast water for reinjection, here in NZ we have enough rain and river water for reinjection at our geothermal sites.
cheers niallnz
RE: Geothermal? Better in some states?
I saw ths post and figure I should throw in my 2 cents. I work for PG&E (the local electric and gas utility) and I am the electric transmission planning engineer for this part of N California. I have had the opportunity to see some of these units operating.
Currently, the Geysers Geothermal complex produces about 900 MW. The total installed generation capacity is around 1800 MW, based on "nameplate" generator output. From what I understand, there is enough heat in the ground theoretically extract about 4000 MW. In fact the 230 kV and 115 kV transmission system that connects the site to the rest of the grid was built out to handle this massive amount of power.
To put this in perspective, the peak electric power demand in California is around 45,000 MW during a hot day in summer.
Lack of water is the primary limit on steam (and power) production. The injection of treated wastewater supplements the natural process and has stabilised the steam fields. If steam is withdrawn at a faster rate than can be replaced by natural percolation of rainwater or reinjection, the the power production will decline. When the plants started operating in the 80's peak output was around
The current plants are operated in a open cycle. After the energy of the steam is extracted in a turbine the steam is vented. There are closed cycle systems that condense most of the steam and reinject. but these systems add cost and compexity and were not around for this application when these plants were built 20 yrs ago. In addition there is a whole bunch of nasty toxic stuff that comes out with the steam: sulpher, mercury, H2S gas, and chlorine. Really depends on the geology of the area. Some of the geysers units had to be shut down because of the chlorite deposits in the wells were creating HCL acid and eating up all the equipment. The underground rock matrix that contain the steam can be also be damaged if the steam is removed too quickly. this can plug up the bore hole and requires very expensive specialized drilling equipment to fix.
Here is a good article that talks about repowering of one of the generating units (I worked on the interconnection for this project):
http://w
Thanks,
Gene
RE: Geothermal? Better in some states?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Geothermal? Better in some states?
Currently some of the steam is recycled and reinjected, I think about 20%. Nature provides most of the recharge, however this takes time. Currently, output is pretty stable a 900 MW. I think I see addition wastewater reinjection projects in the future and expansion of production.
Maybe someone could calculate how many liters of water, converted to 700 deg F dry steam, is required to produce 900 MW when run through 23 steam turbines, with 20% of the water reinjected?
Sounds like a question on a thermo exam!
RE: Geothermal? Better in some states?
I asked the same question when I was working there. I think the part you may have missed in ehanes75's post is just how nasty the steam coming out of there is. As an example, when I was driving through the area I was not allowed to exit my vehicle or roll down the windows, nor could I even stop the vehicle for more than 5 minutes without special permission and supervision. I had to drive straight through and they even timed my passage. I got lost once and had to explain why I took too long to reach my destination.
As it was explained to me, reclaiming the steam would be problematic just from the H2S standpoint, let alone the other toxic substances. To allow the turbines to vent to the atmosphere is "natural", i.e. it was already happening there before the plants were built. For instance, around the wells, there is no vegetation and new vents spring up all the time, killing whatever vegetation there was in the vicinity. To capture and treat the steam just to reclaim the water would mean to take ownership of what comes with it, which means the cost of dealing with it.
RE: Geothermal? Better in some states?
It makes wonder - again - does Raser have better technology or more experience in this field than others have? Seems a risky undertaking if you haven't been in this kind of operations before.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Geothermal? Better in some states?
Thanks ehanes75 you pretty much answered my question. Still seems to me that if they are running at less than possible due to lack of water condensing more of it and pumping it an all the poisons right back down the bore would still put them ahead. There's probably an equation floating about that sez NO!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com