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WikiProject Engineering (Rated Start-class, Low-importance)
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In California, cogen plants are subject to permitting, to control their emissions of NOx and CO. There have been recent advances in very low NOX units.--Billymac00 01:42, 5 September 2007 (UTC)


I've redirected the hatnote to the disambiguation page. It's not doing any harm, but do we really need one? Most users entering "CHP" to find this article would arrive here via the disambiguation page, but not the other way round. --Old Moonraker (talk) 07:35, 30 December 2007 (UTC)


Aren't the efficiency numbers given a little misleading? It would be useful to see how the division between electricity and heat is for cogeneration. The amount of electricity that can be produced per input heat unit is reduced when the "waste heat" is used for space heating or anything other than dumping to the lowest temperature possible. Taken to the extreme, it would indicate that we should just burn gas for heating, it gives an efficiency of 98% after all. But, if the gas was instead burned in a combined cycle gas turbin to generate electricty at 60% efficiency, the electricity could be used to drive heat pumps for heating and give a 180% efficiency (if the heat pumps operate with a COP of 3). Is the total efficiency of cogeneration really better than a CCGT driving heat pumps for space heating?(Matthew.homola (talk) 17:54, 17 April 2008 (UTC))

Agreed, treating electricity (high grade energy) and heat (low grade energy) as equivalent is misleading. I think that the comparison to CCGT/Heat pump arrangement illustrates both why the 'efficiency' is not meaningful and why it is not necessarily the most environmentally friendly or efficient approach. As such, it probably warrants mention in the article.

I really don't understand why CHP qualifies for the sustainable energy portal if it is fossil fuel fired. Wouldn't it be preferable to get heat and electricity from green sources? --Ionium Dope (talk) 22:49, 26 October 2009 (UTC)


It is surely essential in any article to have the costs of the technologies, otherwise it is pretty much meaningless. This information is closely guarded by manufacturers, who only reveal it in private tenders as a rule. Hence the links to cost examples are extremely valuable and are not commercial - a commerical link would be to a vendors site, and in any case vendors do not give out prices, except as part of confidential negotiations. Engineman (talk) 15:16, 14 November 2009 (UTC)


  • Support merge on this merge proposal. I will proceed with the merge in about a week if no one objects. Rehman 05:35, 25 November 2010 (UTC)
Seems like there is nothing to merge; a simple redirect would do. If you think I missed any that should be merged, please do let me know here. I will redirect the article now. Rehman 11:26, 22 December 2010 (UTC)

kWe vs kWh[edit]

What is the unit of energy kWe refernced in the mini and micro CHP sections? I think they should say kWh. —Preceding unsigned comment added by (talk) 15:10, 11 February 2011 (UTC)

kWe is a unit of power, not energy. see Watt#Electrical_and_thermal_watts.--agr (talk) 10:49, 21 September 2011 (UTC)


As this is such a niche space, is it worth linking to any providers like Urban Energy? (talk) 06:02, 13 June 2012 (UTC)

External links message[edit]

Can we remove the external links warning message at the bottom of the article? - it seems appropriate to have a list of organizations providing cogen information organized by region.--Wendydi (talk) 02:54, 30 December 2012 (UTC)

On what basis Wendy? Saying it "seems appropriate" doesn't help me really. I want to understand your point.--Graham Proud (talk) 09:34, 27 February 2014 (UTC)

Merger proposal[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
The result of this discussion was to merge. --Article editor (talk) 22:10, 11 April 2013 (UTC)

I'm proposing to merge Cogeneration and Trigeneration. There little information in Trigeneration that's specific to trigeneration as opposed to cogeneration. In the introduction section, it mentions that trigeneration is a subset of cogeneration that also allows cooling, but that is it. --Article editor (talk) 21:47, 21 March 2013 (UTC)

Support. Go for it. More a term to fill free trade mags than a concept that is so fundamentally different that it needs a distinct article. --Wtshymanski (talk) 15:03, 22 March 2013 (UTC)
Support. Agree to merge. Trigeneration is a subset of cogeneration and not notable enough to be a separate article.Phmoreno (talk) 15:07, 22 March 2013 (UTC)
Support.Good idea, please have at it! snacks [talk] 17:04, 22 March 2013 (UTC)
Support. Fully agree with this logic Pahazzard (talk) 19:11, 22 March 2013 (UTC)
Comment: It looks like there's a consensus building around merging, but I'll leave the section up for a full week (from March 21) to let people discuss. --Article editor (talk) 03:58, 26 March 2013 (UTC)

The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

Combined heat and power plant needs an article[edit]

This type of plant is certainly a related but distinct topic (currently a redirect leads to here). Such an article exists on almost ten other Wikipedias, see iwiki links at pl:Elektrociepłownia. --Piotr Konieczny aka Prokonsul Piotrus| reply here 09:22, 25 February 2014 (UTC)

Hi Piotrus, thanks for your keen interest in the energy sector. I SO WISH I was multi-lingual, and really admire people who are! However I am wondering if your question is one of language. The topic (and this article) of Cogeneration already includes Combined heat and power plant. The Google Translate version of the example you gave describes a cogen plant. If I haven't understood your question please let me know! By the way, you might be interested to hear of Quadgeneration which Coca-Cola are using to put bubbles into Coke! MAGIC!--Graham Proud (talk) 01:44, 27 February 2014 (UTC)
I did a bit more thinking...always helpful to do that BEFORE one answers a question, not AFTER! In the glossary of the reference text I wrote for the power generation course I teach, I have two SEPARATE entries for Cogen and CHP. I defined Cogen as the integration of an industrial process that needs heat with thermal electricity generation process that produces heat. The combined process is considered to have efficiency much higher than the individual processes, as the electricity generation process exhaust would otherwise be described as waste heat. On the other hand I wrote these words about CHP: Supply of both heat and electricity to an enterprise or premises. The heat may be for use in one or more industrial processes, or may be for occupant comfort. So, having thought about it a bit summary there is just not enough to distinguish the two that, in my opinion, would justify a separate article. Even trigeneration doesn't deserve its own article as cooling is just another form of heat-pump-style equipment integrated into the CHP plant.--Graham Proud (talk) 02:03, 27 February 2014 (UTC)
@Gproud:: My basic concern is that a process =/= a plant where it is carried out. I think even in your own definition this distinction exists. "As an amateur, I would think it would be like a difference between steam engine and the thermal power station article. Or smelting and steel mill. Not a perfect analogy, but I hope that the process =/= plant logic makes some sense. Since this distinction is supported by a number of other Wikipedias, (besides Polish, also German de:Heizkraftwerk/de:Kraft-Wärme-Kopplung, Russian and others) I think it is something to consider. And yes, you are right that we already have a section on plants at Combined_heat_and_power_plant#Types_of_plants; I suggest we split it as a start. There are elements of a physical plant that should not be discussed here: common layout, construction issues, economy, biggest/famous facilities... On a final note, as an amateur, I'd like to see a clear explanation/chart of power plants. Are all nuclear power plants CHP plants? How about all coal, gas and oil plants? What types of plants are not CHP? Don't worry about answering it here, rather, if you can, consider answering this in an the 'pedia (at the very least, the "Types_of_plants" section I linked could use a good rewrite to make it more friendly to amateurs like me. --Piotr Konieczny aka Prokonsul Piotrus| reply here 08:06, 27 February 2014 (UTC)
Good call, I like your style, wanting to distinguish process from plant. Although in practice it may be a little harder to tease out the distinction. And I like that you have correctly measured my definitions as supporting your argument. We have the situation though, that "cogen" is just as much an adjective describing a plant as it is a name of a process. If I was to swing hard on the analytical side, it is a bit of a stretch elevating "cogen" to process "status". It's really just an approach or an arrangement, not like a landmark innovation. Using your examples, the steam engine and smelting were both innovations. Their arrangement into power stations and steel mills has simply been a matter for the incremental progress of industry. Reflecting on the German example you have given, I just don't see enough difference. Now not that I am suggesting this for a moment, but I have seen some Wikipedia enthusiasts display a penchant for merging articles, and maybe these two would be a target? It's only when articles get huge that they support a split. Have a look at the talk says "Maybe is not as clearly distinguished as in Germany". The short answer to the question that you asked me not to answer is, most CHP are gas fired, typically Gas Turbines. Have a look at the books I have been working on at my user page. On the topic of biggest or most famous facilities, please have a look at the work we have been doing here and then think about this: countries must invest in nation-building infrastructure like dams and power stations if they are going to drag themselves out of despair. The countries with good economies now are the ones that invested in infrastructure 50 years ago.--Graham Proud (talk) 09:29, 27 February 2014 (UTC)
I just noticed the Merger Proposal above. See what I mean?--Graham Proud (talk) 09:31, 27 February 2014 (UTC)
Fair enough; I am not going to insist on a split now - we can wait until there's more content. I do think that a split will be justifiable eventually, but if an expert like you don't see a pressing need for it right now, I will defer to your authority. Will try to stub few Polish plants near my hometown instead, as noted on the list page. --Piotr Konieczny aka Prokonsul Piotrus| reply here 10:22, 27 February 2014 (UTC)

Too much emphasis on trigeneration[edit]

Tri-generation is over emphasized. Cogeneration is much more common and is widely used in heat using industries. The biggest problem is the tirgeneration diagram in the lede, where a cogeneration diagram should be. Phmoreno (talk) 20:43, 17 August 2014 (UTC)

hmm, it seems you are one of the people who created the problem on this page, fix it yourself. [1]] 00:48, 27 September 2014 (UTC)


this sentence: "As a whole, the European Union generates 11% of its electricity using cogeneration, saving Europe an estimated 35 Mtoe per annum a day.[39] "

-lacks time-date reference, which renders it unintelligible.

-the expression "per annum a day" is nonsensical: it probably should be either daily OR yearly.

-reference 39 leads to the news page of but (as expected for a newspage) has long expired and yields error 404: the linked content is lost. (talk) 16:29, 13 January 2015 (UTC)

ref 2011 - [2] Mion (talk) 21:50, 14 January 2015 (UTC)
35 Mtoe was removed, the numbers where part of a possbile 2020 target, not the actual numbers. Mion (talk) 21:55, 14 January 2015 (UTC)

Why Recycled Energy Development?[edit]

While I was editing this article, I noticed that Recycled Energy Development along with its management names are mentioned 3 times in different sections. The text does not substantially contribute to the knowledge of cogen, except to provide wikilinks to the company and founder articles. This appears to be WP:UNDUE. So what we need to do here? Z22 (talk) 14:07, 7 April 2015 (UTC)

By looking around, it seems that the company is a relatively new company. It does not appear to be exceptionally notable in the field to the point that quotes from executives should be used in the article. Any thoughts? Z22 (talk) 14:20, 7 April 2015 (UTC)
See WP:SPAM, its removed. Mion (talk) 22:39, 19 May 2015 (UTC)