[Originally posted at EcoGeek. I have some further thoughts about this in response to a comment to the original story. Those are appended at the end.]
Concrete is not often the greenest material choice, particularly since concrete production is one of the largest single sources of carbon emissions globally. But, for wind turbine towers, the use of concrete bases can provide a number of significant benefits, including reducing the amount of concrete needed for the footings for a tower by more than two-thirds. Concrete bases can also be more economical to install and can provide faster construction times for wind towers and also can raise tower height to increase power production.
The wider footprint of the precast concrete base also adds stability to the foundation of the tower. With the precast concrete base, load is spread over a wider area, and a simpler ring footing can be utilized, which results in a 60% – 70% reduction in the concrete needed for the footing of the tower. This can result in a net reduction of the total amount of concrete used. The ring footing is easier to construct as well, since the problems associated with a mass pour can be avoided.
In addition to the construction benefits, the concrete bases increase the overall tower height to raise the turbine into more powerful winds or to allow the use of larger diameter blades. Metal towers are reaching limits for transportability and constructibility, but adding precast concrete tower base can add 30 meters (almost 100 feet) of height to the tower. This can allow larger diameter turbines to be used with existing metal towers.
Concrete tower bases can also be locally produced, rather than needing specialized manufacture as with steel towers. Precast concrete sections for these bases are actually more transportable, since they are produced in sections that are assembled together once on site. Concrete is also a sturdier product, which is less susceptible to damage and rusting and does not require regular painting like steel.
Atlas CTB White Paper (PDF)
via: North American Windpower
My additional comments are more broadly on the topic of information sources for blog writing than on the particulars of this article, but it is in reference to this article that I make my points, so it seems reasonable to add this here.
An EcoGeek commenter thinks we are “thoroughly debased of values and corrupted by advertising” because this article cited a whitepaper produced by a company that has developed this alternative for the market in the United States. In fact, much of my original source information for this article came from an article in North American Windpower magazine (an actual paper magazine that I was reading while waiting for my flight to Washington DC last week). But I could not find a link to an online copy of the article, so I used the manufacturer’s whitepaper as a source for further information, and provided a link.
To my mind, there is a lot of information in the whitepaper, and for some people who want to delve further (particularly people in the wind industry – I’d like to think that maybe there are a couple among the EcoGeek readership – who had missed earlier information about this particular approach), providing reference to source material was only meant to be beneficial. I felt that there was a lot of good information about the numerous benefits offered by these tower bases, and really had to pare things down to keep the article to a reasonable size.
Wind power has become one of my areas of specialty. I read the trade magazines and I’m conversant with issues in the industry. I think Hank didn’t stand up for me as much as he ought to have, particularly in this case, because, while I was repeating the information in the whitepaper and in the original magazine article, I happen to agree with the numerous benefits enumerated in those places. As I was reading the article, I was thinking this makes perfect sense. We may not always dig as deeply as we should, but this is a case where the writer understands and agrees with the information being presented, and I was not simply regurgitating the content of the whitepaper without understanding it.
I don’t believe I was unduly influenced by the manufacturer’s spin. Yes, I see a number of upsides to this. But I think that my own understanding of the engineering (admittedly coming from an architectural perspective, but not unaware of the issues involved) is good enough to see the benefits in pouring a ring foundation as opposed to a mass foundation. I also know that concrete requires less maintenance than exposed steel. I also know that there are real limits on the transportability of wind tower components. I’ve seen more than a few of them on the road in person. So there is an industry benefit to getting an extra 30 meters while being able to keep using existing steel towers. I can see some industry caution about marrying steel towers to these bases, because it is new. But there is always industry resistance to anything that is new. And I don’t think the engineering on these is so outrageous that it would be problematic.
Certainly, the whitepaper is going to have some measure of bias and positive spin in favor of the company. But this is some of the first information available about the particular development, and in order to bring information about new technologies and innovations to EcoGeek readers, we regularly work from industry press releases, marketing brochures, whitepapers, and other sources of information. I suppose I could wait ten years for the peer-reviewed case studies that analyze installations with these bases, and show how they have performed, but that’s missing the point.
We are going to use manufacturers’ information, including press releases and whitepapers, as well as other sources to learn about new and interesting and exciting technologies, and we’re going to use that information along with our own judgment, experience, and understanding to write about them. It’s pretty much how things work. The fact that interesting information comes from a whitepaper (as well as from an industry magazine article) does not diminish the fact that it is still interesting.