Photo © Flickr DraconianRain
A recently-released report announced that the use of precast concrete bases can actually make wind turbines sturdier, more efficient, and less resource-intensive to produce. According to the Atlas CTB White Paper, the wider footprint of precast concrete bases adds stability to the foundation of wind turbines and can reduce the amount of concrete needed to install them by 60-70%. The precast bases also make it easier to raise taller turbines into more powerful winds, and their rapid construction time means that more turbines can be built.
Photo © Flickr Lance Cheung
Concrete and wind turbines have a strange relationship — the material requires tremendous amounts of energy to produce and accounts for 5% of global CO2 emissions, but it is essential for the installation of large wind turbines. Several months ago a report stated that hundreds of offshore turbines could potentially collapse into the sea due to poor grout mixture being used in the bedrock and poured concrete base. Then it was reported that the base, made of cement, sand and gravel, was not holding the turbines firmly enough, causing some turbines to shift several centimeters since installation.
Precast concrete bases eliminate these issues — the turbine’s load is spread over a wider area, and a simpler ring footing can be utilized. A ring footing is also easier to construct, since the problems associated with a mass pour can be avoided. Not only that, the towers’ height can be easily raised with concrete bases, allowing turbine heights to be tailored to increase power production. Taller turbines can use larger diameter blades and have better access to more powerful winds. Precast concrete tower bases can potentially add 30 meters (almost 100 feet) to the height of a wind turbine tower.
Concrete is largely impervious to to damage and rust and is one of sturdiest building materials in the world — but it is responsible for a large amount of emissions in the construction industry. What do you think – does harnessing this durable material to produce green energy justify its use?
Via Ecogeek
One of the biggest problems with wind farms is still and will continue to be land use. More and more space will be needed and there will be push-back on this point. Getting the turbines much further up in the air could be a viable solution: http://organicconnectmag.com/wp/2009/12/from-war-machine-to-clean-energy/
Well it isn’t concrete per se that is responsible for the emissions you state, rather it is the production of Portland cement, obviously the base component of concrete.
However these days it is common to use recycled materials such as fly ash (from coal fired power stations), blast slag (from steel furnaces) and silica fume (by-product of silicon alloy manufacture from coal/quartz), in cement. This reduces the amount of Portland cement in a mix, and thus reduces emissions. There have also been developments in producing cement that absorbs carbon dioxide from the atmosphere during hardening.
This combined with the long service life of concrete, and excellent properties when well designed, would make concrete an exemplary choice to build wind towers.
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