The wiki for power=plant says if the object has an output of less than 1 MW it is not a plant. Fine.
What about the other way round? It is easy if there is a place with more than one generator operated parellel. One node for every generator, one area for the plant.
But there are also lots of single generators having an output of 10 MW and more (as single object). A single nuclear reactor can output up to 800 MW. Any guideline as from which output one should tag such an object as plant instead of generator?
The same question had been risen in the german subforum with one suggestion to use plant if the power is fed into the high voltage net only. Does that fit?
Second issue:
The wiki for power=generator includes this example:
To tag a 15 MW biomass gasification combined-heat-and-power generator use:
Is that proper tagging for such a combination? Isn’t this rather a plant comprising several different generators? So to say
At least 1 digester converting biomass into biogas
At least 2 gas combustion generators converting biogas into electricity and heat
Also isn’t the whole object including pre-digestere, post-digester, storage tanks, bunker silos, gas filter etc. a bit large for a single power=generator?
No idea if that counts in OSM. That is why I am asking here …
My major point is that mapping such a facility as generator containing another 3 generators is not a good idea imo. I still believe mapping the generators one by one plus the complete facility as plant separately is a better approach.
Btw. that proposal is not yet approved and faces a lot of resistance at the time being, so I would not start making use of it yet.
No, it advises that facilities which output less than 1 MW are normally not power plants.
This threshold has been introduced lately to give context about the industrial character of such facilities.
The other criteria about the mandatory high voltage connection is similar: you mostly need high capacity connection to allow an industrial power generation facility to operate.
In 2013, we already perceived the difference was about domestic versus industrial with less ability to get the practical limit, so 1 MW tries to fix this.
Power generation became an industrial activity in developed countries and power=plant is clearly linked to that in OSM. It should be used when we face an industrial facility which the main purpose is to produce power. For any other situation, domestic, backup, whatever, power=plant shouldn’t be used.
It’s perfectly fine to map power=plant with a single generator and find several colocated generators without surrounding power=plant if they’re not there for industrial purpose.
The purpose shouldn’t matter, you wrote that power production became an industrial activity and I agree, but that’s regardless of the purpose. If e.g. an university produces their own heat and electricity, this power plant would still be industrial regardless of the educational and research purpose of the university.
It would still be considered as industrial at campus scale as it is eventually maintained by a contractor and may be not captive but actually selling the energy to the grid.
In developed countries, you will find it listed in official registries with according references. These official sources help a lot to choose to create a power=plant in OSM or not.
It differs from domestic solar panels, a way lower scale and maintained by home owner (or not maintained at all ).
In a world with distributed renewable energy this is in my opinion a distinction that at least has some problems. Considering a wind turbine: Is it a generator? Technically yes, obviously. Does it feed into higher voltage grid? Yes probably. Is it in a broader sense some sort of industrial activity for generating electricity? Probably, but very debatable. As the technology has evolved we now have wind turbines with 10+ MW compared to just a few 100 kW ~15 year ago. Same things applies to solar, e.g. a large building with flat roof full of solar panels can easily reach 1MWp: Clearly the main purpose is to produce electricity.
The arbitrary (even if only as aproximate guideline) 1 MW doesn’t capture this very well.
I would argue a generator is - according to the the physical definition - just the generator (commonly the turbine) indepenently of the energy output. A plant is then just a collection of generators. If it’s not practicall (or unkown) then for large facilities the individual generators can be omitted and it can be treated as a single black box.
The distribution of generation leads to get more and more standalone generator outside of any power plant. It doesn’t change the difference between domestic and industrial facilities.
It’s possible to describe local practices about power generation on each country page here (and create missing ones): Power generation - OpenStreetMap Wiki
That’s the current framework, a generator is a device, the plant is the facility and doesn’t always exist. It has been like that since 2013.
I should have noticed from the very beginning in the topic title: A generator never becomes a power plant. A generator is a device sometimes involved in a power plant, when the facility actually exists, but these are always two independent features.
Thanks, that is exactly what I have been musing about. To put in into some mapping examples:
An industrial nuclear plant is always mapped as a plant regardless of wether it comprises only 1 reactor or a dozen. The reactors can be mapped as generators within the area of the plant but this is not obligatory.
The same applies to an industrial gas turbine plant - it’s mapped as plant regardless of wether it comprises 1 turbine or a dozen. It also does not make a difference if such a plant is operated as permanent power (and heat) supply plant or if it is used as backup system for grid stabilization only.
Consequently a combined heat and power generation plant feeding the output into the public grid, as described in my second issue above, should be mapped as a plant comprising the generators for biogas (step 1) and electricity (step 2).
In contrast a standalone gas turbine as power supply or power backup for a factory should be mapped as generator.
A standalone wind turbine is a generator. A cluster of windturbines being connected to a windpark should be mapped as plant.
Now to the edgy cases:
A run-of-the-river turbine plant comprising more than 1 turbine would be mapped as plant (with the turbines as separate generators) according to the above said although the whole plant is incorporated in a single building.
In contrast a small installation on a tiny river consisting of merely 1 small turbine could be understood as a standalone generator.
Where to draw the line between generator and plant here? The quantity of turbines? The output? Or is everything incorporated in a single building just a generator?
A single PV-panel is not mapped as generator in OSM. We map a cluster of panels as generator regardless if the quantity of panels is a handful of some thousand. As an internal guideline we accept a cluster with an output of approx. > 1 MW to be plant, anything below is understood as generator. By doing so the distinction would not be the difference between
but merely the size of the installation. Another approach would be the distinction by the designation of an installation, following
By doing so also a minor installation with just some 50 kWp could be a plant when the whole output is fed into the grid agains remuneration.
In practice, the generator will be mapped as a node and the plant will go on the building over it.
If you wonder if you should add the plant on the building in case of small facilities (or even when there is no building and the turbine is directly plunged in the river), it depends on the context. In developed countries, this kind of facility will look too tiny to be called a plant while in developing countries, sometimes it feeds a whole village so it’s definitely a plant. That’s why I recommend to have a local discussion and document the outcome on Power generation - OpenStreetMap Wiki
The generator is always drawn and when the facility is industrial enough, we add the power plant over it and don’t change the generator. The generator doesn’t upgrade into a power plant.
The parking area sample does not fit. Parking spaces can have different designation so a separate mapping does add value which is not the case for PV-panels. Mapping those separately would only add noise to the database without benefit.
When mapping 200 panels of a PV installation as separate generators one would end up with a power generator with an output of 80 kWp comprising 200 generators with an output of 400 W. Does that make sense? I’d say definitely not.
That is not what I am talking about. In most cases the mapper cannot clearly separate the single generator units of a PV plant
What to map as generator here? A single panel? A row? A block? The lot?
The register says the whole is a installation of 2.000 kWp. No further details available. Pragmatically I would map this simply as 1 unit. In the given case as power=plant, following the 1 MW guideline. By doing so I do not see any benefit in adding separate power=generator to any of the components.
In case the installation would have an output of 950 kWp I would map the whole unit as generator, following the same guideline.
The distinction is merely made by the size of the installation, not by making a difference between a device or a facility. It’s just a fact and I don’t see a problem with it.
That is the point where a lot of the inconsistent tagging in OSM arises from. When mappers have to consider a context or make a personal assessment of a given situation on the ground. I know that we cannot avoid that in many cases although it would be better to have well defined rules
I respectably disagree: both have separate value and usage. Plant perimeter is useful for land use inventory and relatively consistent information to process for grid planning. Panel footprint is necessary to assess actual generation potential and risks that weight on the most important asset of the plant. As your example shows, not the whole perimeter of the plant is covered by panels, it’s valuable to know exactly where.
You won’t use it and it’s fine. I can’t know if anyone couldn’t do anything out of it in the future.
By the way, more than 10 years after OSM community began to map PV-panels inside solar farms in France, the French government paid an IA company to seek for them on aerial imagery. I bet we weren’t wrong to map them.
I would map any arrangement of panels that cover the most accurately as possible their area as power=generator. Like this, for instance but I would also agree on a single polygon that covers the bigger part apart from the central cluster:
And the power=plant will go on the fence around them.
By doing so we would have two tags (power=plant or power=generator) for the same feature in reality (solar panels) and it leads to bigger problems. A solar farm is not a solar panel (or a cluster of solar panels), but we don’t always have a farm when only a few panels are installed somewhere, that’s it.
Not only we can’t avoid that but we couldn’t be sure the exact rule we set is enforced. So we would better working on consistency between generators and plants than a single method to map them.
Thanks mate, I appreciate your feedback and I do agree with your definition of generator and plant in nearly all aspects.
Apparently there is just a minor misunderstanding regarding PV installations.
You are talking about plants and panel footprint now. I was pointing at single panels within a generator. This are definitely 2 different issues.
Mapping the panel footprint within a plant is fine, although not obligatory. Mapping the total area covered by the panels as polygon with power=generator and the total outline of the fenced area as power=plant is fine, although I myself normally forget about the generator polygon in such cases.
But that was not my point. When I said “A single PV-panel is not mapped as generator in OSM.” I was talking about mapping each and every single panel in a PV installation tagged as generator.
In the above example that would mean to draw exactly 5544 minipolygons tagged as
(being part of the surrounding area tagged as power=plant + plant:output:electricity=2000 kWp)
Would that make sense? I’d say definitely not. Either we define a generator to be a panel cluster (of different size) or a single panel. Using the same tag for both will just cause confusion.
PV installations are definitely a bit different from other generators/plants. That’s not a problem, we just have to be aware of it.
Okay I didn’t got this difference, thank you for being more precise;
Well, I wouldn’t map myself every single panel indeed, but anyone who wants, can.
What I’m certain of is we shouldn’t map both a cluster and individual panels inside. It’s whether 5544 polygons with power=generator + generator:output:electricity=360 Wp OR the surrounding panels footprint power=generator + generator:output:electricity=2000 kWp, not both.
And inside a larger polygon around the fence with power=plant + plant:output:electricity= 2000 kWp
The guideline about panel could be we encourage using power=generator for a whole and consistent panels cluster but it doesn’t make it invalid it for individual panel if anyone wants to (use devices=* to describe the population inside the cluster)
We would face a similar issue if someone starts to instal several wind turbines on the same mast for instance.
I would suggest to distinguish between a PV panel and a PV generator. Personally I do not think it makes any sense to map individual PV panels as I said above. Not adding any value to the data, just noise. But in case someone wants to, we should have a separate tag for the panels, like power=photovoltaic_panel.
One reason is to avoid confusion beween a panel and a panel cluster, another reason is to avoid creating a generator comprising other generators if someone starts mapping both. The latter would damage the quite simple rule that an installation comprising more than 1 power generator usually forms a power plant.
Alternativly mapping a panel cluster as generator and indicating the quantity of panels by devices=* sounds good.
Coming back to the example above: You have drawn 7 polygons as generators of the plant. Which additinal tag do you think of? There is no information about the output of those blocks so the only information carried by these polygons is the area they cover (unless you start counting the panels and calculate the output value yourself). Anything else?
I largely support this option. Because creating a tag for individual PV-panels will collide any cluster composed of a single panel (the singleton ambiguity). It would also make the hierarchy plant / generator weaker.
Individual panels are likely to be mapped on houses roofs.
Each polygon should get power=generator + generator:source=solar + generator:method=photovoltaic + generator:type=solar_photovoltaic_panel + devices=* if anyone is open to count them.
Their value is indeed to document the covered area.
The lack of output is not so bad: the only information we have (2000 kWc) is at the plant level, so it should go on the power=plant perimeter and unless further information we assume those 7 polygons count for the total.
In case of further information, a different breakdown could be mapped as well, depending on what we learn.
I agree. So it would be wise to recommend this approach and discourage to tag single panels as generator.
It is not worse than mapping 3 panels individually as power=generator and than combine the 3 in another outlinge tagged as power=generator. Both is poor tagging and should be documented as such.
In this case all the other standard tags for power generators do not add much value as they are redundant to the same tags used with plant:*. Besides the covered area the only real additional information would be the output of each cluster tagged as generator.
I do not say one should not map these standard tags but I wouldn’t.
Anyhow, thanks again for your input. I think we have come to a sufficient definition of generator vs. plant and it would be great to document this in some detail, either on the wiki pages for power=plant and power=generator (which are just offering a rough distinction at the time being) or on a separate disambiguation page.
From a practical mapping perspective in developing regions, we often encounter single high-capacity generators that function as standalone facilities.
Would it make sense to distinguish based on operational integration (grid connection level, transformer infrastructure, fenced compound, etc.) rather than purely MW output?
welcome to the forum. Yes, it makes sense to do so, and has been pointed out in some of the post above. The 1 MW is just a guideline, primarily in the context of photovoltaic plant which are a bit different from other power generating facilities.
When a single high capacity generator serves as primary power source for an area it can surely be mapped as power=plant, which will then be added to the whole (often fenced) area, whereas the generator can be mapped in addition as a node within this area, but the latter is optional, not a MUST do.
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