Cleantech Can Scale Up More Than You Might Think

Given the opportunity to work with some of the brightest minds in the cleantech industry who are creating everything from micro hydroturbines to small, lightweight, three-wheeled electric cars, I’ve learned that bigger is not always better. Yet in the case of a new wind power innovator, their approach has been to go big – in this case, tall – or go home.

Their innovation is made possible by combining ideas from the past with the design technology and capabilities of today.

In Hanover, Germany, a 100-meter wooden tower is rising that – when completed – will be crowned with a 1.5-megawatt wind turbine weighing 100 tons that will produce electricity for about 1000 households. The tower, currently more than 90 percent complete, will be the equivalent of a 30-story building and online by end of year.

The company responsible for this towering achievement is a German cleantech startup called TimberTower, who I briefly mentioned in an earlier post on renewable energy sources. This innovative company, headquartered in Hanover, has made it their mission to develop wooden towers that can be used as the base for wind turbines. (At its simplest, a wind turbine is composed of a tower, a drive train, and rotor blades. TimberTower is strictly focused on the towers, taking a vendor-neutral approach to the other components, “future-proofing” the base as technology advances).

While wood might not seem like the most cutting-edge material, it turns out that if you’re going to build a massive wind turbine tower—the large heights are necessary to increase yields—there are several compelling reasons to create them out of wood.

First of all, wind turbines with conventional steel towers cease to be financially viable at hub heights greater than 85 meters, largely owing to the rising price of steel.

Secondly, since TimberTower uses flat panels of laminated wood to construct its towers, the loads are easily stackable and transportable, in contrast to steel tower segments. The entire TimberTower kit can be transported using standard container vehicles, rather than having to be transported as an abnormally-sized load—a logistically challenging procedure that can be up to 10 times more expensive.

Third, building towers out of wood makes sense for a forest-rich region like Germany, where the raw materials can be easily sourced close to the point of use from woodlands given the stamp of approval by the largest sustainable forest certification system in the world.

Using a timber alternative for a 100-meter tower saves around 300 tons of sheet steel, which requires an enormous amount of energy to produce. And at end of its life, the wooden components that make up the towers can be easily disassembled and reused for construction purposes, or even transformed into wooden pellets (about 180 tons worth) for energy recovery.

Pretty nifty. But perhaps the most interesting aspect of TimberTower’s innovation is the way it borrows an idea from the past and reinvents it for the future: windmills, after all, have used wooden towers as the base for their turbines for centuries.

Just goes to show that cleantech—innovative and futuristic as it is—isn’t always about discarding the old ways of doing things. Sometimes it’s about taking an idea that’s been around for a long time and helping it reach new heights.

Have any Question or Comment?

3 comments on “Cleantech Can Scale Up More Than You Might Think


Dear Susan,

Having made several unsuccessful attempts in the past to get free software from

Autodesk by pledging my status as inventor of a revolutionary rotary-wing aircraft, I’ll try again — hopefully addressing the right person this time.

This said, I don’t need $150,000 software for my patent drawings — wire-frame 3D will do!

Is there anything like basic Autodesk 3D-CAD software (ideally a streamlined version of Autocad Inventor) that comes with CD-based or on-line tuition for autonomous learning?

Maybe women are better at the kind of off-the-box thinking it needs to sense the potential interest of my proposal to Autodesk, i.e. the return-on-investment (if there’s any investment involved at all!) for Autodesk in terms of publicity, in case my invention were to unleash a massive trend towards airborne personal mobility likely to trigger transition from road-bound to airborne individual intercity traffic…

Looking forward to your reply flying to my mailbox, I remain

Sincerely yours

Oscar Fleury


Reçues 20

CH-2400 Le Locle

Le Locle, 5th October 2003



If you’re not quite sure whether my pledge is of outstanding relevance to Autodesk, please forward it to your Big Boss!

Paul Preminger

Dear Cleantech Administrator:

About four years ago I published a comment on the Internet about the need to build higher towers for wind turbines in order to obtain the benefit of the higher velocity and more constant winds at higher altitudes.

Since then I have continued to publish comments about our design and the designs presented by others at least once a month or even more often!!

To date the interest we have recieved has been small even though we can show that we can produce one 200 metre high tower at a cost considerably lower than the cost of a 120 metre high steel tower taking into consideration all the factors involved in both alternatives.

Furthermore the schedule for the construction of a series of 200 metre high towers with one dual set of equipment can be at a rate of less than one month per tower. This sure beats wooden towers!

The loading limit for a 200 metre high tower of our design can be as high as a 5 mw HAVT or a 10 MW VAWT. Can wooden towers approach that level of height and loading? Sure they can but it would take one hell’eva pile of wood and bolts and a lot of time to do so!!

Our design of high towers is based on using conventional climbing cranes that are seen on the city skylines every day for the placement of the concrete and accessories.

The technology for high, cast in situ, post tensioned reinforced concrete towers is actually quite simple and it has been around for over 100 years!!!

Our towers are designed just like concrete chimneys except for the fact that we use post tensioned reinforced concrete whereas chimneys are usually built without the post tensioning.

Some critics have indicated that the problem will be to raise the turbine equipment to the top; we have solved that problem by including a compact permanent heavy lift crane at the top of each high tower for just that purpose. That kind of technology has also been around since before the Empire State Building was erected!!

I am a civil engineer with over 40 years experience in the project development industry and I am certain the our design of any height of tower is sound and that the tower will still be safe and standing 50 years after commissioning!!

The ROI for a tower that lasts 50 years is higher that the ROI for an identical tower that lasts for any amount less than 50 years!

A 100 metre high wooden tower will not last as long nor will the cost be competative with our design. As a Canadian that has worked on a number of major industrial projects in North and South America I have had experience with wooden structures exposed to the elements; they are esthetically pleasing but they will require a considerable amount of maintenance during their shorter life.

Everyone should take note that the Toronto tower, which was constructed in situ using conventional reinforced concrete in less time that it will take to build the wooden tower in Germany, is three times higher than our 200 metre high design and it will likely remain standing and in service for at least another 50 years from today.

I have at times stated my opinions quite forcefully. I am sorry if my opinions sometimes detract from the designs of others but I “Calls them Like I Sees Them”!!! If my comments are true and technically correct, they can not be considered derogatory or unprofessional!!

Lets not publish items about technology that has been superceded many years ago.


Paul V. Preminger


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