Wind Power Up Close
A visit to a Japanese onshore wind farm
Where I live in Japan there are fairly strong, generally westerly, winds a lot of the time. In winter our house rarely gets settled snow because most of it blows past horizontally. Now as we enter the hot and sweaty time of the year, the wind means that where we live is notably less hot and humid as other places, particularly large cities like Tokyo, but also including places just a few miles inland where the temperature can be a few degrees hotter. It may not seem like much, but trust me 32°c is a lot nicer that 36°c
As a result of this wind there are lots of wind farms in the area and some have been around for close to 20 years (and possibly over 20 in the case of a couple of turbines I pass regularly that no longer seem to function).
Anyway a few weeks ago we were on our way back from a night out in Masuda at the other end of the prefecture (we stayed the night there) and decided to hike somewhere on the way back. The weather forecast was dull to rainy so we wanted tarmac and the option to drastically shorten the hike if need be. The winding few km of road connecting the ridge top wind turbines of a windfarm above Gotsu seemed ideal as we could park near the middle walk to one end then walk back to the other.
One of the things that shocked me was just how much infrastructure had been built for them. There was a two lane road connecting all the turbines and transformer substation at one end. Some of this is probably Japan’s Ministry of Concrete doing it’s usual trick of overbuilding for pork reasons but not all of it.
These things are enormous and their size means that constructing them is not as straightforward as you might assume. The helpful information board (with its lack of live wind and power generation data) by the main road explained that the towers are 80m (260 ft) tall and the blades 45m (150 ft). That means you have to move 45m blades and large (30+m?) tower sections into place and you can’t have the cranes and other construction equipment (and the blade/section transports) sink into the earth as they put them together. It is possible tarmacing the road was overkill but the rest of the massive construction was needed. This video of how they got the bits up the hill from Gotsu port is fascinating. Even with specially built roads at the end it was a major logistical exercise to move everything from the port where they were offloaded to the wind farm site. And then they had to put the bits together….
By walking up to the turbines you begin to grasp just how big a 80m tower is and how impressive it is that humanity has managed to design and build 45m long blades and a generator that can rotate 360° around on top of the tower. Even more impressively these towers and turbines have to be stable in strong winds and (since this is Japan) moderate earthquakes. Now it’s true I don’t know how many towers on the Noto peninsular survived the Jan 1 quake but that was exceptionally strong (we felt it here several hundred miles/km away) and given how much else collapsed there having wind farm towers also collapse is not a surprise.
The information board told us the turbines would generate electricity if the wind was between 3 and 13 m/s (approx 7 - 30 mph) which is quite a decent range and about what we get most of the time but far from being able to handle typhoon speed winds (90 mph or more). However it is clear that the amount of electricity generated when the wind is 3m/s is going to be a lot less than that generated when it is 13m/s.
As walked below them on a day of light variable winds, it was very evident that one benefit of these huge turbines compared to the farm of smaller ones on the coast road between Izumo Taisha and Taki is that the big ones retain considerable momentum that must smooth out generation in gusty conditions. That smoothness seems to come at considerable expense in terms of construction.
The Izumo wind turbines are perhaps 20m tall with 3-5m blades and they required nothing special in terms of cranes or special transportation. I saw some of them being installed - the crane was similar to ones used to replace power poles or pylons and the tower, generator and blades all fitted on the back of a standard flatbed truck or two. They were constructed flat on the ground and then raised vertical closing a hinge at the base of the tower/pole (see this google streetview image for a good view of the hinge). Yes they need a road for maintenance access but the road needed is half the width and appears to be just packed gravel in places.
Back to the Gotsu ones. They are not all used to generate power all the time. From observation when the wind is blowing one or two are always in action and the rest are started up as demand requires. However even when they are not generating power they are slowly rotatating at a rate perhaps one rotation every 10 minutes (I didn’t time it), presumably because if they don’t rotate slowly the bearings will become unbalanced and things will break.
Turning them on is not that fast. We walked past one as it was being spun up; a process which took a few minutes and included some rather ominous creaking sounds. I found myself checking for directions to run in the event that the creaking was a prelude to something rather more serious. I suspect that if you are within a 100m circle of the tower then your survival in the event of a failure is going to be mostly a matter of chance. Once in full operation they are quite quiet but there is definitely some noise. A general gentle mechanical noise from, I guess, the generator as well as a periodic swish from the blades. Neither is especially loud but I can understand why people who live near wind farms object.
If you look at the zoomed in picture of one of the turbine hubs above you can just make out the ladders that are attached to the hub so that maintenance workers can move their way around and eventually attach ropes so they can descend next to the blade to inspect it for dents etc. One of the channels on Japanese TV had a series of programs a year or two ago about giant machinery which included an episode where they showed how the inspection and maintenance staff climb up the inside of the tower and then eventually make their way out through hatches on the generator section to inspect the blades and exterior of the tower. Sadly I have failed to find video of that but the construction video I embedded above shows the workers using the same egress points as they connect the blades to the generator.
Going and seeing the turbines in person brings home just how skilled you have to be to do this sort of thing. In addition to a complete lack of acrophobia, you need serious rope/climbing skills as well as all the technical knowledge to build/inspect/maintain etc. the generators, blades and so on. These people are not going to cheap to hire which is yet another cost for whoever it is that decides to install these monster machines.
And yet despite all the very impressive monster engineering there are problems. There was considerable coverage of the failed offshore wind turbine that broke of Massachussets recently1. One thing to note is that these turbines are about twice the size of the ones I visited:
In addition to the public relations disaster at Vineyard Wind, Big Wind is facing a crisis caused by simple physics. The turbines now being deployed onshore and offshore are failing far sooner than expected. Why? They have gotten too big. Yes, bigger wind turbines are more efficient than their smaller cousins. But the larger the turbine, the more its components get hit by the stresses that come with their size and weight. The GE Vernova Haliade-X wind turbine used at Vineyard Wind stands 260 meters high and sweeps an area of 38,000 square meters. That means the turbine captures wind energy over an area five times larger than a soccer pitch.
But here’s the critical part: its blades are 107 meters (351 feet) long and weigh 70 tons. In addition, the rotor of the massive machine spans 220 meters. For comparison, the wingspan of a Boeing 737 is 34 meters. In other words, the turbines at Vineyard Wind are nearly as tall as the Eiffel Tower and each of their blades weighs more than a fully loaded 737.
The wind farm I visited is about 15 years old. It’s not in the same ball park as the off-shore US one but I do wonder at what the expected life span is (I’m thinking about 20 years) and what the plans are for when they get dangerously fragile. Based on the older inoperative turbines that I mentioned above, I suspect they will be gradually be used less and less before finally not being used at all. At which point you have to wonder if there are plans to refurbish them or take them down. Based on observation no one seems to be in any hurry to do either.
Also, despite the aforementioned impressive engineering they don’t appear very good at the generation of electricity even when they are working properly. According to a notice on the substation at one end, the maximum power it expects to handle, which is presumably the maximum that can be generated is 20.7MW or 2.3MW/turbine. Presumably that only happens when the wind is at the higher end of the range. According to this official Shimane prefecture page (google translate) the average wind speed is either 5m/s or 6.1m/s (not quite sure I understand the difference) so that suggests an average generation amount of 20% to 30% of the maximum. That same link above says they spent about JPY 6.4B ~= US$ 60M (at the exchange rate at the time) to build this site. That $60M paid for an average of perhaps 6 MW of power generation i.e. 6MWh every hour. That’s not a lot of power, particularly since it is intermittent.
That intermittency is a problem. A recent substack2 notes the inherent unreliability of windpower. Something that a second one also notes when working out just how much South Australia can do to decarbonize its electricity3.
Fortunately here in Shimane we have the Misumi power station which is 2GW of coal (apparently using highly efficient generation techniques according to those who know) to keep things going when the wind isn’t blowing and the sun isn’t shining. The local power company recently built a second generator (construction started 2018, in service 2022) there doubling capacity from 1GW to 2GW. I have been unable to figure out how much it cost, but I’m fairly sure it was less that the wind turbine equivalent. Based on the estimate above you would need 166 wind farms like the Gotsu one to replace it. That’s roughly US$ 10B at the exchange rates when it and the wind farms were being built. There is no way that it cost anywhere close to that and it also takes up way less space than even the single 6MW average Gotsu wind farm.
Wind turbines are impressive engineering. So was the battleship Yamato, which we visited the museum of a couple of months ago. As far as I can tell wind power is about as effective as the Yamato.
Wind power varies as the cube of wind speed. So, pick a nominal wind speed and call whatever the turbine can produce as power output at that speed the rated power. If wind speed drops to half of nominal, turbine output power drops to one eighth of rated. So, wind power volatility, in effect, amplifies wind speed volatility and this is plus the fact that wind cannot be dispatched are the reasons why wind generation cannot be baseload.
The good thing about Japan's wind farms; you've a major amount of metal stored that may, eventually be salvaged and utilized elsewhere.
Coal's good, nuclear is better for Japan in my opinion,but ideally, being self sufficient energy wise without fuel import's best.
For Japan such might be geothermal,wave and/or tidal power generation. The latter two experimental, and geothermal has, even assuming the heat sink 'neath the islands is grand enough, never been scaled up to supply anywhere near Japan's power needs.
None the less, clever folks, those Japanese,if anyone can develop viable geothermal,wave and/or tidal power generation, it's them!
Meanwhile going coal and nukes and such will take lots of cement, keeping Japan’s Ministry of Concrete happy.
& next time Naikaku Sōri-Daijin stops by your house for a cup of tea Francis, feel free to tell him I know a guy who knows a guy that'll sell ya'll all the coal you need, FOB Alaska! ;-)