Keywords: wind, wind farm, wind speed, capacity factor, onshore, Netherlands, globalwindatlas, GWA, KNMI
What I want to do is show my neighbors around Munich that windfarms make more sense where there's more wind. GWA has a nice GUI, which everyone can understand. But are their wind speed and capacity factors accurate enough to convince anyone ?
nl.wikipedia Windturbines_in_Nederland, has both GWh and lat / lon coordinates of a dozen onshore windfarms. Compare that data with GWA, globalwindatlas *.tif and KNMI the Royal Netherlands Meteorological Institute WINS50*.nc :
# https://nl.wikipedia.org/wiki/Windturbines_in_Nederland onshore
# realcap = average electricity generated / maximum possible = (GWh / 8.760) / MW, %
# + average windspeeds at 50 100 150 m [2019 2020 2021] from https://dataplatform.knmi.nl
# + windspeeds and gwacap from GWA https://globalwindatlas.info/area/Netherlands
# written 2022-09-07 Sep 16:47 by bz nl/knmi/avwindspeeds.py
gwacap realcap MW GWh Name ix iy lat lon knmi50 knmi100 knmi150 gwa50 gwa100 gwa150
59 37 429 1400 Noordoostpolder 115 108 52.702 5.6148 6.89 7.71 8.26 7.89 8.95 9.91
63 45 383 1500 Fryslân 105 121 53.01 5.28 8.37 8.98 9.4 8.65 9.48 10.04
53 NaN 300 NaN Prinses_Ariane 100 115 52.883 5.0779 7.14 8 8.59 6.95 8.2 9.21
55 35 102 314 Krammer 79 59 51.657 4.1762 6.78 7 7.46 7.52 8.44 9.46
59 32 63 175 Delfzijl 149 139 53.329 6.9814 7 7.42 8.04 7.6 8.78 9.88
58 41 50 180 Slufterdam 73 71 51.934 3.9831 8.35 8.83 9.28 7.84 8.93 9.64
53 32 27 75 Sabina_Henrica 85 60 51.672 4.3954 6.41 7.16 7.87 7.04 8.16 9.25
49 29 18 46 Kabeljauwbeek 83 47 51.383 4.2951 6.17 6.88 7.61 6.51 7.82 8.99
53 23 16 32 Hagenwind 143 77 51.954 6.5453 5.94 6.82 7.61 6.87 8.14 9.32
49 26 16 36 Oud_Dintel 86 58 51.625 4.4272 6.25 7.02 7.8 6.52 7.76 8.92
49 NaN 13 NaN Nieuw_Prinsenland 86 58 51.625 4.4272 6.25 7.02 7.8 6.52 7.76 8.92
46 21 12 22 Neer 129 47 51.309 5.9463 5.71 6.65 7.42 6.13 7.43 8.56
44 30 10 26 Reusel_de_Mierden 106 46 51.327 5.1188 5.78 6.69 7.39 6.01 7.3 8.39
What really matters for wind power is not windspeed per se, but electricity generated and €€€.
A wind turbine that can generate 4 MW maximum (aka "rated" or "installed" MW)
might generate 1 MW on average, with fluctuating wind.
This ratio, here 25 %, is called the "capacity factor" or "efficiency factor",
"Cap" or "CF" for short.
(If we know electricity actually generated, GWh per year, then
Capacity factor = (GWh / 8.760 ) / max MW.)
Look at the columns "gwacap" from GWA and "realcap" from nl.wikipedia above. Why are the GWA Cap factors almost twice as high as nl.wikipedia, and the plotted GWA windspeed curves so steep ? It's entirely possible that I've made mistakes along the way. However, as an old engineer, I like to have a rough idea of where data comes from -- what's measured, what's extrapolated -- and I like spot checks. For GWA for the Netherlands, I see neither. Can you help ?
For comparison, capacity factors in Germany in 2020 from Wikipedia Wind_power_in_Germany:
39.82 % offshore, 23.97 % on + off, 21.74 % onshore. About 20 % of the total is offshore, 27 / 131.7 TWh.
I'd welcome open planning of windfarms over a whole region or province, with estimated cap factors, costs, and profits on the web for every citizen to read and discuss. As much as engineers and professors wish for "rational" decision-making, transparent and understandable, windfarm owners and politicians have their own agendas. Does anyone know of open windfarm planning, anywhere in Europe ?
Germany has very little pump storage (citation needed), so wind and solar energy are thrown away when they exceed network capacity. This "Geisterstrom" or "Phantomstrom" is paid for anyway, to the tune of €761,000,000 in 2020.
How does electricity generated go up with windspeed, for real windfarms ? The standard model is cubic, wind power ~ A v³ (MacKay pp. 263-264). These dozen windfarms are too few to fit a powerlaw v^p (I've tried); we need more data.
Finding KNMI data at sites near given lat lon is not quite trivial; see "Introduction-to-Netherlands-wind-data-with-xarray" under gist.github.com/denis-bz. I used pyproj Lambert conformal -> lat lon -> ix iy, but am no expert --
An expert is a person who has found out by his own painful experience all the mistakes that one can make in a narrow field.
WINS50 - Winds of the North Sea in 2050
Dutch Offshore Wind Atlas
scholar.google.com Global Wind Atlas \
MacKay, Sustainable Energy -- without the Hot Air 2009, 368p, pdf free
This rough answer is not exact, but it's accurate enough to inform interesting conversations.
See also: Windspeeds-and-windfarms-in-Bayern, Windfarms-in-Germany, Windpower-Weibullmodel, German-electricity-daily under gist.github.com/denis-bz.
Data on windspeed -> electricity generated especially welcome.
cheers
— denis-bz-py t-online.de 9 Sept, 31 Oct 2022