Windmills have several important speeds:<p>- Cut-in speed<p>- rated speed<p>- shutdown speed<p>- survivable speed<p>Cut-in speed is the speed at which the windmill starts to generate power, rated speed is the speed at which it makes maximum power, shutdown speed is the speed above which the furling mechanism can't operate or has no more effect, which causes the machine the shut down (anything above rated speed is essentially wasted), finally survivable speed is the speed which will not cause damage to the machine.<p>If the wind speeds are increasing that's mixed news because you will make more power between cut-in and rated, but given that the top end will likely <i>also</i> increase and that wind power is v^3 the destructive force of that top-end you might lose the machine entirely, only a very small relative speed increase could make things go from survivable to catastrophic.<p>This is because all of these speeds given above are designed in to the system when it is conceived and the survivable wind speed is not something that you can easily modify once a machine has been built.<p>So mixed blessing, unless it is only in the mid-range and the top-end is unchanged.
Nice to know I haven’t been imagining things! In 20 years of flying it’s really seemed to me like I’ve had way more high-surface-wind days (which I’ve arbitrarily defined as >20 kts) than when I started. It used to be a rarity and now it’s well over half the days of the year.<p>I know there’s a lot of local variation, but even with that in mind it’s been noticeable.
According to a two-year-old study, the opposite will happen and climate change will weaken wind energy. <a href="https://www.theguardian.com/environment/2017/dec/11/global-warming-will-weaken-wind-power-study-predicts" rel="nofollow">https://www.theguardian.com/environment/2017/dec/11/global-w...</a>
There is a fairly interesting sci-fi story[0] about an ever-increasing world-wide wind, I recommend it, and hope it doesn't go that way.<p>[0] <a href="https://en.wikipedia.org/wiki/The_Wind_from_Nowhere" rel="nofollow">https://en.wikipedia.org/wiki/The_Wind_from_Nowhere</a>
I understand the need for a study to quantify it, but I don't understand how the increase itself can even be called a finding ?<p>I thought it completely obvious that there is more energy in the global "climate system", so everything is amplified. When the sun heat is increased on two surfaces with different heat capacities and albedos, the temperature difference between them is increased, thus the pressure difference, thus the wind.<p>What am I missing ?
An odd thing I learned about wind turbines recently is that their peak efficiency is capped at exactly 16/27, or about 60%:<p><a href="https://en.m.wikipedia.org/wiki/Betz%27s_law" rel="nofollow">https://en.m.wikipedia.org/wiki/Betz%27s_law</a>
Global warming -> increased in wind speeds -> massive boom in windmill construction -> extracting energy out of the wind causes slower wind speeds -> Saves the planet from global warming.
>>> Princeton University scholar Timothy Searchinger, one of the study's authors, says researchers expect wind speed to continue to increase, he says, which has multiple positive effects.<p><a href="https://xkcd.com/605/" rel="nofollow">https://xkcd.com/605/</a>
Wind turbines are dirty sources of energy.<p>They do not supply consistent baseload energy.<p>Turbines are just giant machines built off the backbone of oil and natural gas.<p>Humanity doesn't make turbines with renewable energy.<p>Trucks move steel.
Earth movers navigate.
Cranes push up structures.<p>All of this requires diesel fuel.<p>These figures aren't accurate, but precise enough.<p>Diesel ships transport critical turbine cement, steel, and plastics.<p>A 5 Megawatt turbine requires 900 metric tons of steel.<p>150 Tons - concrete foundations
250 Tons - rotor hubs and nacelles
500 Tons - towers<p>Let's play with some scenarios w/ conservative back of the napkin calculations:<p>If wind was 25% of global demand by 2030 *(w/ capacity factor of ~40%)<p>2.5 Terawatt hours of wind turbines require 500M tonnes of steel. (w/o towers, wires, transformers. etc…)<p>30-40 gigajoules/ton are required for Turbine steel.<p>500M tonnes of coal to make this much steel.<p>60 meter foils. (theat each weigh ~20 tons) make up the 4 MW turbines.<p>Glass fiber reinforced resins are made of hydrocarbons.<p>Glass is made with natural gas furances.<p>The rotor’s mass of such a turbine is ~20 metric tonnes. (About 75 million metric tonnes of oil)<p>Coal makes iron.<p>Coal + petro make kilns.<p>Naphtha and Liquefied natural gas make synthetic plastics for
fiberglass.<p>Diesel makes ship fuel.<p>PS: In 2016, the global volumetric production of steel was ~1500 Million tonnes. (+/- 10%)<p>The wind turbine hydrocarbon based lubricants industry is fast growing ---- <a href="https://www.globenewswire.com/news-release/2019/02/20/1738574/0/en/Lubricants-for-Wind-Turbine-Market-To-Reach-USD-226-1-Million-By-2026-Reports-And-Data.html" rel="nofollow">https://www.globenewswire.com/news-release/2019/02/20/173857...</a>