Vestas Multi-Rotor Wind Turbine: 3 Blades Good, 12 Blades Better

July 5th, 2016 by Tina Casey

Hmm…We’re going to take a wild guess that the new multi-rotor wind turbine design from Vestas is going to encounter some headwinds when it comes to site selection. The single tower bristles with 12 blades mounted on four separate rotors, adding a new level of aesthetic concern to the issues already faced by today’s generation of tall wind turbines.

However, it’s a big world out there. If Vestas can prove that its new multi-rotor design ups the efficiency ante on wind energy harvesting, the big-picture result could be improved opportunities to locate wind farms without disrupting nearby stakeholders.

The New Vestas Multi-Rotor Wind Tower Design

The new wind turbine design first sailed across the CleanTechnica radar last spring, when Vestas announced that it was beginning installation of the behemoth at the Risø test site of the Technical University of Denmark near Roskilde. In collaboration with the University, the plan was to break the “scaling rules” on cost-efficient wind turbines.

Vestas has been keeping relatively quiet since then, but it finally provided an update last week on Facebook, when the multi-rotor concept produced its first kilowatt-hour. Apparently the company was so excited about switching on the equipment that it could not wait for a formal press release. Here’s the meat of the post:

Looking ahead, the extensive tests of the concept turbine’s functionality will continue: “Right now we are testing various software functions. One of them is the cut-out functionality, i.e. if the concept demonstrator stops when it reaches the cut-out wind speed. Another one is the yaw system supervision that shuts down the turbine in case the yaw misalignment exceeds certain values,” explains Erik Carl Lehnskov Miranda, Senior Specialist, Electrical, Load & Control at Vestas.

If you caught that thing about “yaw,” that’s a nautical reference for unintentionally pitching to the left or right.

Take another look at that photo up top and you can see how why minor glitch in one of the turbines would need to be offset ASAP by adjustments to the others, so realtime monitoring and correction is critical to the success of the project.

The risk factor could account for why the company is being rather cautious about equipping the new turbine. Rather than hanging its current generation of nacelles on the tower (nacelles refers to the enclosures for the working parts of the turbine), Vestas has furnished the turbine with four 1990’s era V29-225 kilowatt nacelles modded out with new controls and other features required for testing.

Speaking of site selection, turbines at the test site are limited to 74 meters, which explains why the new turbine clocks in at only 74 meters.

By way of comparison, in 2014 Vestas introduced a “taller” tower for low-wind locations which comes in at more than 140 meters.

Levelized Cost Of Wind Energy Goes Boom

The cost of transporting tall wind turbine towers accounts for a big chunk of the cost of wind energy compared to other sources (aka the levelized cost of wind energy). If the multi-rotor approach works, then the tower transportation costs can be spread out over more rotors, bringing the levelized cost of wind energy down.

Here in the US, wind already began crowding out coal in 2011, with a significant assist from low natural gas prices. With additional cost and efficiency gains, it looks that kind of help won’t be needed for long.

At its launch last summer, President Obama’s Clean Power Plan dropped some huge hints that renewable energy will be the face of the future, crowding out natural gas.

Presumptive Democratic nominee for president Hillary Clinton has also made it clear that if she wins the General Election this fall, opportunities under her Administration for new natural gas wells (specifically, those using hydrofracturing technology) will be few and far between — if new standards for public health and environmental impacts are adopted.

Stay tuned, because the Interior Department is already working on a review of the federal coal program, which could end up folding public health and environmental concerns into the cost of new leases and royalties for coal extraction on federal property.

Follow me on Twitter and Google+.

Photo: via Vestas.









Appreciate CleanTechnica’s originality? Consider becoming a CleanTechnica member, supporter, or ambassador — or a patron on Patreon.

Sign up for our free daily newsletter or weekly newsletter to never miss a story.

Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.

Latest Cleantech Talk Episode