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Geothermal Power, and Puna Geothermal Venture
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08-27-2018, 04:03 AM
What I am missing is an answer to how twice the arsenic and ten-times the mercury found at PGV as compared to the Geyser's geothermal fields could be called not "high levels of toxic elements"
--------- It comes from deep in the ground and is then pumped back where it came from. They aren't pouring it all over the ground.
08-27-2018, 04:09 AM
08-27-2018, 11:09 AM
quote: What you are missing ironyak is that you are comparing the compositions of geothermal steam (at the Geysers) with geothermal brines in Puna. Where the Geysers geothermal fluids leak to the surface, you find widespread lead and mercury contamination of the local streams - as well as mercury deposits ( Epithermal Precious-Metal and Mercury Deposits in the Sonoma and Clear Lake Volcanic Fields, California, By James J. Rytuba, In: Rytuba, J.J. Ed.., Active Geothermal Systems and Gold–Mercury Deposits in the Sonoma–Clear Lake Volcanic fields, California. Soc. Econ. Geol. Guideb. Ser. 16, pp. 207–261.) You will find that paper here: https://pubs.geoscienceworld.org/books/b...edFrom=PDF More on that compilation is located here: https://pubs.geoscienceworld.org/books/b...ld-mercury You might also find this article interesting: https://www.researchgate.net/publication...mal_system where they mention extraction of some 4500 tons of mercury in the area of Geysers geothermal field.... Which may be why there is a town near Geysers named Mercuryville.... I don't recall any history of mercury mining in Hawaii... But leilanidude had it right as well: what fluids PGV brings to the surface, with dissolved minerals and compounds, for the greatest part, go back into the ground. You seem to be intent on fearmongering - had there been any potentially toxic element in Hawaii's geothermal fluids that are higher than those in California, (or Iceland, or Indonesia, or Philippines, ...) that would be the only one you would be concerned with... And God forbid that we should talk about the environmental effects of continued combustion of oil; or those associated with the manufacturing of solar PV panels and the required batteries to make that technology compatible with a modern society.... But, of course those impacts happen elsewhere and we don't need to worry about those...
08-27-2018, 12:16 PM
those impacts happen elsewhere and we don't need to worry
Not only elsewhere, but with huge subsidies. If gas cost $12/gallon, we would suddenly have cars getting 50-60mpg...
08-27-2018, 01:12 PM
"...environmental effects ... associated with the manufacturing of solar PV panels and the required batteries to make that technology compatible with a modern society..."
Yeah, let's talk about those. https://www.ucsusa.org/clean_energy/our-...power.html TLDR: "Most estimates of life-cycle emissions for photovoltaic systems are between 0.07 and 0.18 pounds of carbon dioxide equivalent per kWh" and: https://www.ucsusa.org/clean_energy/our-...nergy.html TLDR: "Enhanced geothermal systems, which require energy to drill and pump water into hot rock reservoirs, have life-cycle global warming emission of approximately 0.2 pounds of carbon dioxide equivalent per kWh." So, PV is slightly better. Yes, there are some hazardous chemicals used in PV cell manufacture. Can you claim that none are used in fabricating a geothermal plant ?
08-27-2018, 02:24 PM
quote: Now we have apples (PV non-baseload), oranges(PV baseload w/utility scale storage), pears (geothermal steam/binary baseload) and potatoes (Enhanced geothermal) in the mix. The Union of Concerned Scientists make no mention of battery storage (although they did note the much larger land-use impact for solar compared to wind...) which also has some CO2 and environmental impacts associated with mining and and refining of lead/lithium/vanadium/pick your battery poison for the utility scale storage.... And since we were talking about toxics associated with geothermal, a list of some of those used in PV manufacture include: "cadmium telluride, copper indium selenide, cadmium gallium (di)selenide, copper indium gallium (di)selenide, hexafluoroethane, lead, and polyvinyl fluoride. Additionally, silicon tetrachloride, a byproduct of producing crystalline silicon, is highly toxic." These are pretty much essential to the fabrication of the PV systems; I can't think of too many that play as large a role in the fabrication of the bulk of the geothermal equipment - the electronics for the control systems undoubtedly would involve similar chemical processes for production of any electronic gear. But the bulk of the mass of a geothermal facility would be conventional steel refining. And the numbers selected for Enhanced Geothermal aren't really relevant to Hawaii's geothermal - at least to the present date - since that technology hasn't been used in Hawaii and (as far as I am aware, hasn't been proven to be commercially viable) at current oil prices. Possibly more relevant in terms of carbon footprint is that enhanced geothermal usually involves lower temperatures and more and deeper drilling than has been traditionally done in Hawaii so the CO2 footprint per MWe generated for enhanced geothermal would be substantially higher than the flash steam/binary that is used by PGV.
08-27-2018, 03:04 PM
quote: Do you think that carbon is public enemy number 1 with nothing else having anything to do with "climate change"? Really?
08-27-2018, 03:09 PM
Do you think that carbon is public enemy number 1 with nothing else having anything to do with "climate change"? Really?
Carbon is the symptom.. Homo sapien is the disease.
08-27-2018, 03:43 PM
geochem - What you are missing ironyak is that you are comparing the compositions of geothermal steam (at the Geysers) with geothermal brines in Puna.
Doh - you are right, my apologies for the bad math again (yes, crow is not so tasty  I have not found a clear set of data to fully compare Geyers' brine to PGV (does one exist?) so I guess I am limited to such statements as:- PGV steam contains less than 50% as much Arsenic as Geyers' steam, but can be up to almost twice as much as Cerro Prieto. - PGV brines contain more mercury and arsenic than Hveragerdi, but less than Salton Sea or Los Azufres. - and so forth with the specific nuanced comparisons. geochem - You seem to be intent on fearmongering I'm sorry you see it that way, but the interest is actually in trying to assess actual data, instead of broad generalities. As others here have suggested PGV brines are comparable to the Blue Lagoon resort and could be used in a similar manner, the misunderstandings are not only on the anti-geothermal side. While "what fluids PGV brings to the surface for the greatest part, go back into the ground" now, that of course has not always been the case. Apparently some would have paid to go swimming in the retention ponds, so consider that a missed opportunity of secondary geothermal benefits.  At the end of the day, it would be nice to see a neutral party do a full analysis on geothermal, as performed here, so we could get at clear facts instead of having parties with a vested interest making sales pitches to the entrenched factions. I'd also like a unicorn and likely have a similar chance of getting either. For what it is worth, I do appreciate you taking the time to engage on the topic and point out any mistakes or misconceptions, I, or others, may have. As I have said many times before, for geothermal to be equally successful here as other comparable areas such as Iceland, then a similar investment by the local, state, and federal governments as well as private industry would be needed - but the history of geothermal in Hawaii has not demonstrated any level of similar commitment and the results reflect that IMHO.
08-27-2018, 04:28 PM
"cadmium telluride, copper indium selenide, cadmium gallium (di)selenide, copper indium gallium (di)selenide"
All of which are only used in the manufacture of thin-film cells (<10% of all cells made), not polysilicon cells. Note that I'm not saying that PV is perfect. I'm saying that geothermal is not the silver bullet so many seem to be in love with. And, it's just a tad disingenuous to bring up the environmental impacts of mining for materials to make batteries and then wave away the impact of all the steel used in fabricating a geothermal plant. Finally, we do have battery technologies that use fairly benign materials. Unfortunately this becomes of battle of economics vs. the environment, as such batteries are not cheaper than the current media darlings of the lithium variety. |
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