Germany's 365m Wind Turbine: Why SPRIND's High Altitude Pilot Matters for Land Constrained Onshore Wind
The Schipkau turbine reached its final height on September 28 with a 300 metre hub, and commissioning is planned for November. GICON claims twice the yield per rotor of a conventional machine; no operating data exist yet.
Wind power is Germany's only renewable source of energy in winter, according to the federal innovation agency SPRIND, yet it is highly controversial in the places it is generated. A turbine that makes better use of ground already occupied by wind farms would ease that problem. In Schipkau, in the Lausitz region, a machine that could be the first of that kind has just reached its full height.
The turbine, built by GICON of Dresden, has reached its final height of 365 metres, according to SPRIND, the German federal agency that backed the project. Its hub sits at 300 metres. That makes it the tallest wind energy installation in the world and the second tallest structure in Germany, behind only the Berlin TV tower. The height sets a record, but its potential use matters more.
Schipkau is a prototype for a second tier of wind capacity. It has a record height and no operating history. SPRIND says high altitude turbines can be added to existing wind farms as a second tier, because winds at that altitude blow more steadily, and it puts the potential at up to 4,000 such turbines in existing German wind farms. The attraction is that output would rise without new sites. The ground, and in many cases the grid connections, already exist.
The height difference explains why a second tier is physically possible. The surrounding turbines in the former lignite region typically stand at just 150 to 250 metres. A 300 metre hub therefore sits 50 to 150 metres above the typical height of its neighbours, which leaves room above them rather than competing with them. SPRIND says it set its sights on high altitude wind in 2020, the first year after it was founded. The machine is a conventional turbine mounted on a steel lattice mast of a commonplace kind, according to the SPRIND project page, and the concept dates to 2020. Professor Jochen Grossmann of GICON and Professor Horst Bendix gave the impetus.
The construction method matters as much as the height. The inner tower was raised from within the lattice mast with a strand jack system, so the turbine, in SPRIND's words, serves as its own crane. Final work will take several more days, and SPRIND describes the self raised tower as the feature that lets the turbine do without outside lifting equipment. The method is part of what a second tier would need to be repeatable on many sites.
Operating results will have to substantiate the yield claim. GICON states in its news release of September 28 that winds at greater heights are stronger and steadier, so that at the same rotor diameter the turbine can reach about double the energy yield of a conventional wind turbine. That is a claim against a reference machine with the same rotor, made by the company that built the tower, before a single kilowatt hour has been fed to the grid. It is an engineering projection until the turbine runs.
The pilot is also modest in size. GICON says it will be commissioned with a rated output of 3.8 MW, which is small for a modern onshore machine and is a nameplate figure, not production. A taller mast is likely to cost more to build, and a lattice structure of this height may cost more per megawatt than a standard tower. Those two facts are the strongest objection to the project, and they bound what November can prove. A doubled yield on a 3.8 MW rotor is still a modest absolute output, and the economics work only if the extra energy outweighs the extra steel. Production records will have to establish whether the extra energy pays for the extra steel; construction photographs cannot do that.
The potential scale makes the second tier a policy issue. If all 4,000 units SPRIND mentions were fitted with the pilot's 3.8 MW rating, the total would be 15.2 GW. That is a crude upper bound and an illustration, since it assumes every site is suitable and every machine is the size of this one. GICON says future plants are planned with rated outputs of more than 7 MW. At that rating, 4,000 turbines would come to 28 GW, and more if the machines grow further. Those figures describe capacity that could in principle be added to sites that already carry wind turbines. They do not describe generation, which depends on the capacity factors the first turbine has yet to demonstrate.
SPRIND's project page puts the case for winter plainly: wind power is the only renewable source of energy in that season. If winds at 300 metres really are steadier, the pilot's production record in the cold months will carry more weight than a summer average.
SPRIND says the goal is series production as quickly as possible. That ambition depends on proving the turbine in operation. The turbine has reached its final height, but it has not been commissioned, and it has not produced operating data of any kind. The official commissioning is planned for November. Commissioning and any superior yield are still ahead of it.
November will say whether a 3.8 MW rotor on a 300 metre mast out earns a conventional turbine by enough to pay for the steel. Until the first months of output are public, only the height record is established. The yield remains unproven, and the 4,000 retrofit sites SPRIND mentions remain a projection.