Extreme engineering is becoming the norm as offshore wind continues to scale up. Sweeping the area of 12.3 standard NFL fields each rotation, with gargantuan 140-meter (459-ft) blades, the MySE 18.X-28X will be the largest wind turbine ever built.
Only a week ago, we wrote about CSSC's new H260-18MW, the world's largest wind turbine. Partially constructed at a special and very spacious seaside facility, this offshore wind giant took over from MingYang's MySE 16.0-242 as the biggest wind turbine on the planet.
Now, MingYang has struck back in this game of one-upsmanship with the announcement of something significantly bigger. And it's not like CSSC's 18-megawatt rated effort was small; each of its three blades stretches a near-unthinkable 128 m (420 ft). But the new MySE 18.X-28X promises to push "beyond the 18 MW threshold," with a mind-boggling swept area of 66,052 sq m (711,000 sq ft).
MingYang says it'll handle "the most extreme ocean conditions," including level-17 typhoons with wind speeds over 56.1 m/s (202 km/h / 125.5 mph). Given an average wind speed of 8.5 m/s (30.6 km/h / 19 mph), MingYang projects it will produce 80 GWh of energy per year, "sufficient to supply 96,000 residents."
Why go to the trouble of making these things so enormous? Well, increasing the swept area of your fan increases the slice of sky you're harvesting energy from, and it bumps up your overall yield. But perhaps more importantly, wind farms need to be thought of as total systems. One of the biggest costs in an offshore installation is the work needed at the sea bed to root these huge turbines down and give the wind something to push against.
So both MingYang and CSSC sell these mammoth mega-turbines primarily as cost-cutting measures that'll help bring down the capital cost of wind farm setup, and eventually the cost of the energy they produce.
"Compared to the installation of 13MW models," reads a statement by MingYang on LinkedIn, "the higher output of the MySE18.X-28X would save 18 units required for a 1GW wind farm, shaving off construction costs by 120,000 - 150,000 USD/MW."
Using our advanced math skills, we have deduced this would represent a CAPEX saving of US$120-150 million on a gigawatt-scale project. For reference, the 1.2-GW Hornsea One Project, built using 7-MW turbines, is estimated to have cost "at least UK£4.2 billion" (US$5.153 billion), so while $150 million can't be considered chump change, it might represent a couple of percent on a project this big.
One does have to wonder how big these things will get before manufacturers find a practical upper limit to offshore wind turbine size. Will it be the point at which the blade tips go supersonic? Will it be limited by how big the factory spaces will need to get, or the logistics of towing these goliaths out into deep water bit by bit, and winching their massive blades up to bolt onto their hubs? Will they last as long as smaller turbines, given the outsized loads they have to bear? Will they prove cheaper over the long haul, given that a single unit failure will take out a larger proportion of a site's capacity.
Either way, as fans of extreme engineering we have to marvel at these towering green-energy giants. They'll truly be a sight to see, reaching somewhere around a thousand feet up from the water. Somebody better set up a GoFundMe for Don Quixote; the man's going to need a dolphin and a humdinger of a lance.
You mention blade tips going supersonic. As far as I remember from my wind power course in the 1990s, one of the key elements of the design of wind turbines is to stop exactly that, as it results in loss of efficiency, rapid blade wear and most likely a horrible din. So I expect the rotation rate of these monsters to be quite slow, with a large step-up gear ratio to the generator.