Talk:Geothermal energy/GA1

GA Review

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Reviewer: Pyrotec (talk) 17:36, 23 January 2010 (UTC)[reply]

Starting review. Pyrotec (talk) 17:36, 23 January 2010 (UTC)[reply]

Initial comments

I'd had my "eye" on this nomination for some time, but I had no intention of reviewing it whilst there was a "merge" template on it.

I had a quick scan-read through it; and it appears to be reasonably close to being a GA so I'm not going to quick fail it. What it does appear to lack in places is depth and references. If it can be brought up to standard, it could make GA-status this time round.

I will now do a more detailed review section by section but leaving the WP:Lead until last. At this point in the cycle I will mostly be concentrating on the bad points, not the good one; those will however be covered by the end. Pyrotec (talk) 20:41, 25 January 2010 (UTC)[reply]

Electricity

Y Pyrotec (talk) 21:00, 26 January 2010 (UTC) - Referencing in this section is quite patchy; and it is also not clear what statements in the various paragraphs are unreferenced or are verified using later references.[reply]

I added a couple of footnotes in answer to your next comment, so now 8 out of 10 sentences are footnoted. Does this address your concern?--Yannick (talk) 02:19, 26 January 2010 (UTC)[reply]

Y Pyrotec (talk) 22:41, 27 January 2010 (UTC) - I assume that most of the claims in the first paragraph are based on ref 1. (Lund 2003)[reply]

Most of the claims were actually supported by ref 2 (Fridleifsson 2008) but I've added in footnotes to ref 11 (Lund 2007) because it's closer to the origin of the data and somewhat more explicit. Beware that the footnote are now renumbered as a result.--Yannick (talk) 02:19, 26 January 2010 (UTC)[reply]

The obvious, unasked and unanswered, question is what 24 countries?

How should this list be presented? 24 countries is too many to list in a sentence. They're listed and footnoted in a table in geothermal electricity, but that format leaves a lot of white space. A map comes to mind, but several of the important countries are geographically small and would be easily missed. Can you suggest another presentation?--Yannick (talk) 02:19, 26 January 2010 (UTC)[reply]

You could provide a link (I accept that there is a {Main} link, but a (see Geothermal electricity#Geothermal electric plants) could provide an quick solution). Pyrotec (talk) 21:15, 26 January 2010 (UTC)[reply]

I've been trying to put more thought into this. Avoiding national bias will be complicated. For example, it isn't very useful to include all of Russia when only a small amount of power is produced in an isolated edge of a very large country. Nor is it really accurate to list France when their only operating plant in 2005 was in the Carribean. I'm thinking that a bubble chart of field capacities overlaid on a map of hotspots might be ideal. I am searching for appropriate tools.--Yannick (talk) 00:38, 27 January 2010 (UTC)[reply]

Y Pyrotec (talk) 21:00, 26 January 2010 (UTC) - The first para states that geothermal accounts for 0.3% of worldwide electricity consumption and that it is growing by 3% per annum. 3% of 0.3% is not a lot (0.30%; 0.309%; 0.318%; 0.327%, etc). It's virtually static; I would have expected some comment on this.[reply]

There may be a misunderstanding here: it is the absolute output that is growing by 3% per year, not the percentage share. Global electricity consumption from all sources is also growing, at 2.9% per year, so the percentage share is growing even more slowly than what you calculated. So it is true that the share is virtually static, but could you explain what makes this a notable fact? If 3% growth is considered static, then the global electricity supply is static, and geothermal power is no different. If this was a misunderstanding, could you suggest what part needs to be clarified?--Yannick (talk) 02:19, 26 January 2010 (UTC)[reply]

It is much clearer. I am happy now. Pyrotec (talk) 21:00, 26 January 2010 (UTC)[reply]

Y Pyrotec (talk) 21:10, 26 January 2010 (UTC) - The second paragraph claims that the "largest group of geothermal power plants in the world is located at The Geysers", citing ref 3. That reference confirms Calpine Corporation (Calpine) operates plant there, but it does not appear to verify any claim about it (them) being the world's largest; and largest by what measure?[reply]

I've replaced the Calpine citation with another one that explicitly calls the Geysers the largest field in the world without specifying what measure. The Geysers have long held a widely-known preeminence by a wide margin in any measure - number of plants, installed capacity, realized production, volume of steam, reserves etc. A google search turns up headlines like this. I would argue this is an uncontroversial point that does not require a footnote. Only very recently has one field, Leyte in the Philippines, come anywhere close to surpassing the Geysers, but I have never seen a reliable source claiming that Leyte has actually edged into first place. Are you satisfied with the new citation?--Yannick (talk) 03:29, 26 January 2010 (UTC)[reply]

Y Pyrotec (talk) 21:10, 26 January 2010 (UTC) - Ref 4 is a 372-page pdf report. The relevant pages numbers should be provided.[reply]

I specified the Executive Summary which supports all of the claims backed by this citation. That narrows it down to 24 pages. Let me know if you feel something more specific is needed. I could break up the footnotes and narrow it down further, or I could expand to include all pages that discuss the topics supported.--Yannick (talk) 04:47, 26 January 2010 (UTC)[reply]

Y Pyrotec (talk) 22:26, 26 January 2010 (UTC) - It is not clear what ref 5 is. An author, date, title and International Geothermal Days, Slovakia. Is it a book, a journal article, conference proceeds: its not clear what this is.[reply]

It's a conference proceeding. I fixed the series name and added a link to the article. --Yannick (talk) 02:19, 26 January 2010 (UTC)[reply]

I'm not convinced that the scope of this section is adequate. It provides an overview of world consumption but there is little or no detail, well half of the second paragraph is about California. Iceland, for instance is merely listed as one of four countries producing more than 15% of its needs. In reality has not many people but hugh electrical energy supplies, most of which is used for electricity-intensive industrial purposes, such as aluminium production, with bauxite brought in from places like New Zealand. The is also "talk" to exporting electricity by undersea cable from Iceland to Europe and the UK; or indirectly via hydrogen production.

California produces more geothermal power than any country other than the Philippines, so I don't think this is undue weight. Iceland was once a leader in geothermal power, as noted in the history section, but it is now in 8th place by installed capacity and 4th by share of the national grid. About 17% of Iceland's power comes from plentiful geothermal resources, which helps explain its low electricity prices, but this is not a sole driver. In other parts of the world geothermal resources are not so easily accessible (i.e. deeper, or under harder rock, etc.) and geothermal projects are often more expensive than fossil fuel options. I see aluminium production, electricity export and hydrogen production as consumption-side topics that are largely independent of how the electricity is produced, so I think they would be out of scope of this article. Have I convinced you?--Yannick (talk) 04:47, 26 January 2010 (UTC)[reply]

My "complaint" is not undue weight. Its more a case of do I fail this article against clause 3(a) of WP:WIAGA, or am I seeking more information that could be in conflict with clause 3(b) of WP:WIAGA? I'm leaving this as unresolved and will return to it later. Pyrotec (talk) 22:26, 26 January 2010 (UTC)[reply]

Direct application

.....to be continued. Pyrotec (talk) 21:53, 25 January 2010 (UTC)[reply]

Y Pyrotec (talk) 22:11, 30 January 2010 (UTC) - I don't find petajoules (PJ) a particularly "easy" unit, perhaps that is a personal preference (dis-preference); interestingly the Electricity section provides a conversion to GW-h which makes more sense to me.[reply]

I know what you mean, but I think this is the right choice in this case. To start with, SI energy units are advantageous as discussed on Wikiproject Energy. Units of kW-h and GW-h particularly problematic because they encourage confusion between energy and power, and they are rarely used for anything other than electricity. When it comes to thermal energy, the most commonly used units are BTU's and joules, and the latter is more common in geothermal articles. The use of GW-h almost always indicates that a thermal efficiency factor has been applied, although the manner of application depends on context. In the context of deep geothermal power, GW-h would indicate the electricity output of the plant, while in the case of geothermal heat pumps, they would indicate electricity input.--Yannick (talk) 21:40, 30 January 2010 (UTC)[reply]

However, in 2004 there were (so it says) 270 PJ of geothermal heating, more than half of which was used for space heating (say 135 PJ); and later on it states that 88 PJ was space heating from heat pumps (and there is more detail on the use of heat pumps). So that seems to suggest that possibly heat pumps account for upto 65% of space heating needs, but what about the rest?

That's correct. The other 35% of space heating comes from geothermal sources hot enough that no heat pump is needed, usually through district heating systems. The geothermal water or steam may be piped directly through radiators in people's homes, or there may be other heat exchangers and heat transfer fluids between the source and sink, or the heat may be taken from the outlet of a geothermal electric plant. (Cogeneration.) Were you pointing out a possible discrepancy, or do you think this information needs to be explained in the article?--Yannick (talk) 21:40, 30 January 2010 (UTC)[reply]

I suggest that you add this information to the article. Pyrotec (talk) 22:03, 30 January 2010 (UTC)[reply]

The final sentence about heat pumps and homes aught to be WP:verifiable.
The final sentence in the second paragraph about heat pumps being used essentially anywhere in the world aught to be WP:verifiable.
As aught the final sentence in the third paragraph about desalination.

.....to be continued. Pyrotec (talk) 22:39, 27 January 2010 (UTC)[reply]

I'm not convinced that the scope of this section is adequate. It provides an overview of geothermal heating consumption but there is little or no detail.

Environmental impact

Possibly OK.

I disagree. I've read numerous texts from the Dept of Energy. They all agree that the consumptive water use is equal to or greater than power generation from any other heat source, as it is temperature dependent; with low temperatures being less efficient and requiring more cooling water. All thermodynamic factors are independent of the heat source. The commonly accepted rate of water consumption for a plant with an optimum temperature heat source is 100 acre-feet/year/megawatt. This is a huge impact on water resources.

Here's a post I wrote on another forum:

Geothermal is green except for its very high consumptive water use, about 100 acre-ft/megawatt/yr. And it needs fresh water so the wells and pipes do not get clogged or corroded. One Environmental Impact Report for the Imperial Valley area I read blatantly lied that the proposed geothermal plant would actually produce fresh water from the salty brine at the site, in order to secure approval. As soon as it was built they bought ~ 10,000 acre-ft/yr of fresh water from LA's Colorado River canal.

http://www.sci.sdsu.edu/salton/iidAllegedWasteofWater.html

"Development of Geothermal Power

The Imperial Valley has one of the largest potential geothermal resources in the State. The U. S. Geological Survey delineated six "Known Geothermal Resources Areas" in the valley as part of a program authorized by the Geothermal Leasing Act of 1970. Leasing of federal lands began in 1974 and there are approximately 23 companies presently engaged in some facet of geothermal exploration in Imperial County. (Board, 12, 58-59; T, VIII, 90, 03-04.)

An indication of the amount of water required for operation of a geothermal plant was provided by Mr. Deter of the California Energy Commission who stated that 50 to 100 af of water is needed for cooling purposes for each megawatt year of electricity. Mr. Deter estimated that geothermal development could require between 90,000 and 180,000 afa by the year 2002. (T, II, 16, 17-20.)

These figures indicate that if there is to be any significant development of geothermal power in Imperial County, a large supply of freshwater will be necessary. Use of water from the Salton Sea would require expensive pretreatment that would add substantially to the costs. (T, II, 17, 06-09.) Therefore, conservation of existing supplies of freshwater provides the best source of water for local geothermal development."

Jaeger222 (talk) 22:40, 31 January 2010 (UTC)[reply]

Economics

This section appears to cover "big" systems reasonably adequately. However there is no mention of small domestic sytems, i.e. a heat pump based on buried pipes feeding a single home. These would not appear to have high risks and high capital costs, but they just are not discused.

.....to be continued. Pyrotec (talk) 21:43, 29 January 2010 (UTC)[reply]

Overall summary

GA review – see WP:WIAGA for criteria

Is it reasonably well written?
A. Prose quality:

B. MoS compliance:
Is it factually accurate and verifiable?
A. References to sources:

B. Citation of reliable sources where necessary:

C. No original research:
Is it broad in its coverage?
A. Major aspects:

B. Focused:
Is it neutral?
Fair representation without bias:
Is it stable?
No edit wars, etc:
Does it contain images to illustrate the topic?
A. Images are copyright tagged, and non-free images have fair use rationales:

B. Images are provided where possible and appropriate, with suitable captions:
Overall:
Pass or Fail:

I'm marking this nomination as a "Pass". This is a "balanced" decision: I consider that the article is general compliant with WP:WIAGA but I think that it could be improved in certain areas, such as small domestic installations and "exceptions" to the global pattern. However, the nominator appears to be inactive; so continuing to Hold the review appears pointless. On balance, its a Pass. Pyrotec (talk) 10:52, 5 March 2010 (UTC)[reply]