Talk:Hydroelectricity

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Contents 1 Vandalism 2 Hydroelectricity vs. hydropower 3 greenhouse gas 4 Carbon Release from hydropower? 5 Move 6 Washington 7 Tajikistan 8 Cost 9 Switzerland 10 Units

Vandalism

I note with some dismay that this page gets more than its fair share of vandalism. Does anyone have any idea why? Sendervictorius 08:03, 21 Nov 2004 (UTC)

• It does indeed, I really wonder why? (looking at recent edit history, it's nothing but vandalism and reversions.) It's not like it's George W. Bush or any other such hot topic... 131.111.8.98 04:17, 25 February 2006 (UTC)

Might be related to the Three Gorges Dam project...that would be all I can think of to. So odd. -Fsotrain09 03:37, 5 May 2006 (UTC)

• The IP Address comes from my school. I'd like to apologise for my fellow students behavior. 193.112.136.12 14:03, 6 March 2006 (UTC)
• Should we make this article protected?--MathaytaceChristou 22:07, 5 April 2006 (UTC)

I've semiprotected the article due to above average anon vandalism. --Duk 05:42, 25 April 2006 (UTC)

Good call. I've always found the vandalism of this article rather odd. --Limegreen 05:58, 25 April 2006 (UTC)

Re-semi-protected. Please look at the article's history before unprotecting. Two years of non-stop vandalism by someone who isn't a fan of hydroelectricity. --Duk 15:44, 2 June 2006 (UTC)

I have noticed this page gets vandalised a lot. I would like to question why it is not currently protected? It would save me and others a lot of time if it was.

Thankyou, Omega Archdoom

This hath been created and/or edited in the divine wisdom of The Overlord of Doom. 10:55, 7 November 2006 (UTC)

Wow, 7 instances of vandalism in one day. Pardon my incredulity, but can't we keep this page semi-protected semi-permanently? This is ridiculous! Analoguekid 04:35, 21 November 2006 (UTC)

Hydroelectricity vs. hydropower

Should this article be joined with hydropower? Discuss at Talk:Hydropower. --Andrew 05:16, Feb 3, 2005 (UTC) Hydropower is two words in one. Hydro and power. Hydro means water, power is power. So in the end, hydropower is really waterpower.

1. How does tidal power relate to hydropower vs. hydroelectricity? (can it be considered a form of hydroelectricity?) Also, are there other methods used to harness hydroelectricity besides dams?

2. Needs a bit more in terms of critique of hydroelectric power; "silting, debris collection over time, and upstream pollution concentration" is a major problem; also, disruption of the natural flooding cycle, as seen in the Nile where the Nile river's famed fertility has gone down because natural flooding has disappeared...

3. Side info about dams built with salmon ladders might be relevant

--Confuzion 17:13, 5 Apr 2004 (UTC)

You are allowed to add to this article yourself!

Adrian Pingstone 17:21, 5 Apr 2004 (UTC)

greenhouse gas

why did people delete the greenhouse gas stuff? i find it an important and very valuable addition to the information about dams, and it's a very little known fact that deserves much greater promotion! What else is wikipedia for other than displaying unbiased knowledge, especially when it comes to something that goes against the status quo that control the flow of knowledge in traditional media (like publishers), especially when that information may be of vital importance to the health of this planet. If someone wants to delete the greenhouse stuff, please tell me why.

---

relative cost per kwh? - Omegatron 03:26, Mar 29, 2005 (UTC)

It is pretty hard to equate, because there are many quite local factors at work.

There are geographical economic differences:- Remember the buying power of currencies differs between countries. There are local interest rates, etc. Then there is the expected return on asset value which drives the price expected for the electricity. This is related to the return on investment (and weighted cost of capital) the asset owner needs to return relative to other investments available in that locality.

The cost of hydropower is strongly related to construction costs - the fuel is essentially free, and operating costs are relatively low. Cost of labour, cement, and steel will affect construction costs. Age of plant is also a factor, because all the cheap sites were developed first.

Hydropower costs differ from thermal power costs, which are more strongly influenced by the world price of oil.

Differences in electricity markets in different countries has a bearing too, and affects cost of production operators will bear. For example peaking-plant in Australia uses very expensive to produce power, but only operates when market prices are high.

Here in New Zealand, most power hydopower is base-load and was built years ago, It costs about NZ$0.054 (roughly 4 US cents) per kWh to produce. New generation is economic at about NZ$0.07. Power retails for about NZ$0.14 (10 US cents), including distribution charges and retail margin.

Sendervictorius 09:50, 29 Mar 2005 (UTC)

Carbon Release from hydropower?

From the article: "The reservoirs of hydroelectric power plants in tropical regions may produce substantial amounts of methane and carbon dioxide. This is due to plant material in newly flooded and re-flooded areas being inundated with water, decaying in an anaerobic environment, and forming methane, a very potent greenhouse gas. "

However, IMO, it should be added that this carbon is not from fossil sources, but a part of the carbon cycle in nature.

Move

This article should be moved to Hydroelectric power. Hydroelectricity gets 143,000 hits on Google; "hydroelectric power" gets 611,000.

Hydroelectric Power redirects to this article. MatheoDJ 20:29, 3 November 2006 (UTC)

Washington

The article lists a few places that get a large percentage of their power from hydro. I believe Washington State also gets a lot of its power from hydro -- I've seen figures over 85%. Can anybody get a solid number, with a source? If so, I'd like to add it. Thanks!

---

Tajikistan

I removed Willmcw's entry for Tajikistan, 527,000 GWh (4,000 MW installed); supplies 98% of national demand, from the table showing countries with greatest capacity, because "Capacity" in this context means the maximum energy in a year the country can generate, given the water resources and installed generation. It does not mean the theoretical undeveloped maximum. Many countries, including those in south america, russia and canada have potential for much more development.

Nevertheless, I think the information that Tajikistan has so much undeveloped potential is in itself quite valuable, and think that fact should be added in the main body of the article. The important fact that needs to be stated is how much generation capacity (GWh per year) Tajikistan has now, compared to the theoretical maximum.

I have been unhappy with the "Importance" section, and think it should be redeveloped. I think this is the natural home for the placement of the Tajikistan facts. Sendervictorius 08:27, 30 August 2005 (UTC)

If/when you do this, you might want to slot New Zealand in there as well. According to Reservoirs and dams in New Zealand, there is installed capacity of around 5,300 MW for a similarly small population (but there is also some thermal, geothermal, and wind installations, with hydro accounting for around 70-80%)Limegreen 23:17, 17 December 2005 (UTC)

Cost

There is no mention of construction costs in this article which I think is a glaring omission especially considering that the low running costs are mentioned.

I've removed the following:

Another disadvantage of hydroelectricity is the high construction costs. For example the Hoover Dam cost $49 million dollars to build ($676 million adjusted for inflation) and used 4.36 million yd³ (3.33 million m³) of cement.

It's invalid, since it's not a comparison to any other equivalent generation capacity. Hoover's capacity would cost a couple of billion dollars to build as a fossil fuel plant today. Direct capital costs for new hydro generation today range from $1.50 US per watt to $4 per watt, with smaller projects being more costly per watt. As soon as I have a citation for this I'll add it. This cost is not really different from large fossil plants or what a nuclear plant would ideally cost if their licencing and construction phase wasn't stretched out for decades. It is *less* than the cost per annual megawatthour for wind, since wind plants only have a capacity factor on the order of 33%. Also, cement is only a small part of concrete, not a synonym for concrete. --Wtshymanski 14:59, 2 March 2006 (UTC)

I accept that what i added isn't very good but the construction cost is an important consideration and it deserves some sort of mention. Mabye Hoover wasn't a good example. St jimmy 15:38, 2 March 2006 (UTC)

Perhaps a more recent project or more average scope can be found. It'd be good to have the costs discussed in some manner. Don't forget the cost of flooded land. Also, dams don't last forever, especially if silt is allowed to accumulate. The recent international report on dams should have some reliable numbers. -Will Beback 18:31, 2 March 2006 (UTC)

I think also some reference needs to be made to the large amounts of energy that are used during construction, which comes mostly from fossil fuels and therefore releases a large amount of greenhouse gases. St jimmy 10:34, 3 March 2006 (UTC)

CO2 released during construction of a hydro plant is trivial - there are huge paybacks. For my own amusement I worked out the following for the proposed Manitoba Hydro Wuskwatim generating station, a 200 MW project to be built in Northern Manitoba by 2012.

Wuskwatim will use about 31,300 tonnes of cement.

Does each ton of cement yield 1.5 T of CO2? check - Industry Canada says average energy input is 5 GJ/tonne. To produce 5 GJ take 0.4 T of coal. Each T of coal can make no more than 3.6 T of CO2. So, each ton of cement clinker will result in 0.9 T of CO2 emitted. So, let's use 1.5 T to allow for shipping, grinding, etc.

So, to make 31,300 T of cement we also make 47,000 T of CO2.

A T of good coal will make about 2 megawatt-hours of electricity (in a moderately good plant, say less than 40 years old).

47,000 T of CO2 would be made by producing 47,000/3.6 = 26,112 megawatt-hours of coal-fired electricity.

Wuskwatim will have a net output of close to 200 MW. 26,112/200 = 130 hours of Wuskwatim's output.

So, if the operation of Wuskwatim during it's life results in the displacement of the coal-fired equivalent power output for at least 130 hours (about 5 days), less CO2 would be emitted overall than was required to make the cement for Wuskwatim. I'm neglecting reservoir emissions from Wuskwatim but these are a tiny fraction of the CO2 emissions of a coal plant, at worst, and are more than compensated by my neglect of the true chemistry of coal (coal is never even as much as 90% C).

A lot of cement is made with natural gas, which emits less CO2 per gJ, or even with some municipal waste, some of which was organic material derived from atmospheric CO2.

Some of the cement will be replaced with fly ash, which is a byproduct of coal plants and so has a much smaller net emission of CO2.

You can make similar calculations for the other inputs to the stations, but hydroelectric plants have such huge "pay back" gains that they rapidly make up the energy value of any input.

Unfortunately the above counts as "original research" and is therefore unusable by itself. It seems to be a hallucination among some that commercial power plants don't "pay back" the energy used to build them. I wonder where the hallucination came from. --Wtshymanski 18:55, 3 March 2006 (UTC)

I thought the hallucination was that Nuclear power plants don't pay back the money used to build them. Pendragon39 17:35, 9 June 2006 (UTC)

You mean like Shoreham Nuclear Power Plant or the reactor that Washington Public Power Supply built? This seems to be mostly a US problem, most utilities expect their reactors to make money or don't build them. --Wtshymanski 17:54, 9 June 2006 (UTC)

The general impression is that nuclear power plants cost more to build and decommission than the market value of electricity produced during their expected life cycle. Of course this view neglects to consider the economic benefits of cheap/subsidized energy production. Pendragon39 00:46, 10 June 2006 (UTC)

In the Pacific Northwest there are a fair number of hydro plants slated for decommissioning because upgrading to meet environmental laws costs too much. Its mostly the smaller projects that are more expensive, as Wtshymanski mentions above. See Condit Hydroelectric Project and Bull Run Hydroelectric Project. Condit was looking at about $3 per watt just for fishladders and spillway modification. --Duk

So it's not a hallucination after all. Pendragon39 22:31, 9 June 2006 (UTC)

huh? what? I wasn't commenting about the above arguments being hallucinations or not. Just giving an example of some smaller plants that are no longer economically feasible because of environmental regulations. I agree there should be a section in the article about hydroplant construction costs- does anyone have some good reading they can recommend on the topic? --Duk

Sorry about that. I'm sorry to hear that small scale hydro plants in the US are not viewed favourably. The situation in Canada is different. See small-scale hydro Pendragon39 00:47, 10 June 2006 (UTC)

Actually, many small hydro projects in the United States do succeed - articles about new or refurbished mini- and micro-hydro plants are pretty common in "Water Power and Dam Construction". Not every micro hydro makes sense, but the licencing and financing is much easier than for large hydro. There's a fair number of old mill ponds with a few hundred kw of induction generators making money for some small operator. Economics of hydropower development is worth an article in itself. --Wtshymanski 18:48, 10 June 2006 (UTC)

You mean the economics of small private ventures versus large public investment projects? Or the advantages of having hydroelectric capacity versus foreign dependance (Quebec vs Ontario). Yes, such an article would be more informative than a cost comparison between different energy sources. Pendragon39 00:40, 11 June 2006 (UTC)

Sounds interesting, I'll look for that periodical at the local U's library. There is a farmer who lives near me who put in a small hydro plant on his farm. It required fish ladders (not for salmon though). Took him two years and dealing with over 2 dozen local and federal agencies to get the required permission. Do you know, are most of the small hydro projects you've read about on existing impoundments. I think there are a lot of hydro installations being installed on existing dams, but very few new dams being built for the purpose of hydropower (in the US). I'd love to see some statistics on this (have look but haven't found any yet). --Duk 19:02, 10 June 2006 (UTC)

Re: Small Hydro, what is the minihydro situation in North America? Seems worth mentioning if only because so many "renewable energy" companies include a lot of "small hydro" in their mix. John McPhee's article (quite a while ago) suggested that most small hydro projects were not new dams, but refits of existing (but perhaps unused) mill raceways to drive a generating turbine. Pjmorse 18:52, 12 July 2006 (UTC)

Switzerland

What about hydro in Switzerland?? Peter Horn 21:02, 23 April 2006 (UTC)

Units

I see the table includes expressions such as: USA, 319,484 GWh (79,511 MW installed). I don't understand what it is trying to say. The first unit is watt hours and the second unit is watts. Can anyone clarify what it means?

I was planning to research and annotate this, but haven't yet. I think the first term is the actual annual power production, and the second term is the capacity of the installed generating equipment. --Duk 14:59, 9 Jun 2005 (UTC)

Thanks. What you say makes sense. Bobblewik  (talk) 15:05, 9 Jun 2005 (UTC)

Adding to that: MW is a unit of Power, GWh is a unit of Energy (The sum of power over time). Duk is right, it should be GWh per annum.

Interestingly, in a hydroelectric context, if you divide the GWh per annum by the number of hours in a year, you get a fraction of the installed MW. This fraction is called the capacity factor. 100% capacity factor represents a generator running at full power all year. Obviously, it is in the hydroelectric operators interest (finacial return on capital investment) to keep the capacity factor as high as possible - as high as water supply, electrical load demand, and plant outages would allow.

Sendervictorius 10:19, 10 Jun 2005 (UTC)

GWh means Giga Watts/hour?? Peter Horn 20:57, 23 April 2006 (UTC)

Yes MatheoDJ 20:26, 3 November 2006 (UTC)

I'm doing a research project on alternative energy, and I can't make heads or tails of this in it's current form. It's not cited; where does the info come from? Are these the feasible numbers, or an unrealistic set based on turning every single river in a country into a series of dams and lakes? Am I ignorantly thinking that these are numbers representing a country's total capacity for production in the future, or do these numbers mean something completely different? Could someone add an explanation of what these numbers mean to the article?

Also, in the first paragraph, it lists Canada as the country with the most energy production. In this data it lists USA as having less capacity, but more installed. Which is more meaningful?

MatheoDJ 20:00, 3 November 2006 (UTC)

You're quite right, the tables are confusing. The GWh figures must be annual production (for some year, should be annotated), the second maximum nominal output. So in Canada the capacity is lower, but the capacity factor is much higher. This could be for any number of reasons, but two come to mind: 1) Any pumped storage will be much lower than 100% (intuitively, less than 50% of capacity); 2) Use of hydro as predominantly base-load in Canada, likely more balancing in the U.S.--Gregalton 10:29, 12 December 2006 (UTC)

Also the comment by Senddervictoriious that the financial interest is to keep capacity factor as high as possible - this is largely true for any powerplant, but not as simple as that. Since dam-based hydro incorporates a storage component, it may not be designed to run flat-out, and balancing and ramping may be more profitable - will depend how the local pricing for suppliers works. In contrast, fossil plant will have many periods when the marginal cost of fuel is higher than the price paid, and it won't be economical to run. In other words, all things being equal, any plant with a capital cost will want to run as close to capacity as possible, but all things are never equal. (This is also neglecting any potential monopoly power/collusion effects as in California - if taking plant off-line increases prices sufficiently, it may be profitable to under-utilise plant to drive prices up).--Gregalton 10:29, 12 December 2006 (UTC)

Does anyone know where the world "capacity" figures come from? This should be referenced. I have found output figures for 2004, but they differ from the ones here.--Gregalton 10:40, 12 December 2006 (UTC)

I have just reverted on the table the TWh > GWh switch done. One fact to support first, followed by rough calcs:

1) James Bay Project gives annual output for the first phase which is 10,800 MW capacity of 65TWh, with estimated capacity factor of 60-70%. This would seem to square with most of the plants, allowing for very different capacity figures. Other sources like [2] (sorry, in French, but figures should still be comprehensible) would seem to roughly support that 1,000 MW of capacity converts to somewhat less than 10 TWh. 2) Math would also seem to support. 1,000MW = 1GW, multiplying this by 24 * 365 annual hours gives 8760 GWh, or 8.76 TWh. Allowing for capacity factor of 20-80%, most of the installations would seem to give figures in this neighbourhood. That said, the figures don't all seem to match, or at least it is not clear what methodology has been used. BUT: these figures really need to have a citation so that it can be checked. My apologies if I have made any stupid mathematical errors.--Gregalton 10:03, 15 February 2007 (UTC)

I did the TWh -> GWh switch. The interesting part is that the individual article about the biggest dams seems to do things in GWh, and so do the national production numbers further down the page. But if a GWh is 1000 MW for 1 hour, or 1 MW for 1000 hours, the numbers in GWh seem far, far too small. So something doesn't match. --Alvestrand 19:06, 15 February 2007 (UTC)

Could you be more specific? I don't see the ones that you're referring to, they look (after a VERY brief glance) to be okay. If, of course, 1000 GWh = 1 TWh.--Gregalton 21:01, 15 February 2007 (UTC)

The decimal points got me. I was reading 219,123 MWh as 219 MWh, not 219 TWh. Sorry. --Alvestrand 19:00, 16 February 2007 (UTC)