24 October 2012 17:01 [Source: ICIS news]
By Janos Gal
LONDON (ICIS)--Light-weighting, cost cutting and a drive towards fuel efficiency has increased the popularity and penetration of composites in the construction, aerospace, automotive and wind energy sectors in recent years.
By using composites, the weight of any structure can be reduced significantly, which is especially important for the automotive and aerospace industries where CO2 emissions need to be cut.
In addition, composite structures are more flexible and can be moulded into a wide variety of shapes and forms - qualities which metals do not provide.
These characteristics are especially desirable in the wind energy sector where huge towers and blades are used to generate electricity off-shore in harsh weather conditions.
By using composites, which are made of glass or carbon fibres and epoxy resins systems during a special curing process, the blade's weight can be reduced while remaining flexible. In addition, the right composites help reduce resonance and shaking which can cause problems in extremely windy conditions.
According to a study by BASF, the resin transfer moulding (RTM) process has become the preferred choice for many manufacturers in recent years.
During the RTM process, a desired shape is first made by stitching two or three dimensional forms from glass or carbon fibres. These forms are then placed in a heated mould in a press. In order to remove any air bubbles, a vacuum is then created by suction. The last step is to pump in the two component resins which is then cured in a heated press into the required form.
BASF says that compared with metals, composites can achieve a 50% weight reduction, while the simpler production process allows manufacturers to make highly integrated components.
Germany-based BASF and Bayer both predict that cars will be 25% plastics, including composites, in the next decade. This is because car manufacturers will be forced to reduce CO2 emissions, which can be achieved through light-weight cars.
A push towards lighter cars is also helped by the development of electric cars, which require lighter frames that can increase driving distances between two charges.
Earlier this year, Ford announced it would target weight reductions of up to 750 pounds by the end of the decade in an effort to reduce CO2 emissions and improve fuel efficiency.
To do that, they teamed up with Dow Automotive Systems to develop light-weight materials that can be used in the manufacture of cars. Last week, Ford announced at the Composites Europe 2012 trade show in Dusseldorf, Germany, that it is developing for its Ford Focus range a carbon fibre reinforced plastic bonnet, which weighs 50% less than a standard steel version.
Another good example is BMW's i3 concept, a light-weight electric vehicle which is made of carbon fibre and aluminium.
One drawback could be that technology to produce composite parts on a large scale still needs to be developed and car manufacturers need to install new equipment to align their plants to mass-production.
"If conditions are right, in the future about 60-80% of a car's body could be made of composites," Rainer Kohlstrung at Henkel's Global Product Development said.
Many airlines have also begun to swap old, heavier seats for new composite ones that weigh up to 9kg less.
According to a report by Time magazine, a retro-fitted plane can weigh up to 450kg less and can carry 16 more passengers. This can result in an annual revenue increase of up to $200m (€154m) in the case of Southwest, a major budget airline in the US, the report added.
In addition, by making a plane's wings, tails, airframe and other parts out of composites, the weight of a plane can be reduced by 20% on average compared with conventional aluminium designs, Boeing estimates.
For example, the Boeing 787 uses a larger proportion of composite materials in its airframe and primary structure than any previous Boeing commercial airplane. According to Boeing, its airframe comprises nearly half carbon fibre reinforced plastics and other composites.
However, the future is not all bright for composites. One segment where there is increasing uncertainty is the wind energy sector, where recent government budget cuts driven by the economic downturn have resulted in lower output and capacity reductions.
The wind turbine industry is by far the largest consumer of epoxy resins and composites and any cutback in wind energy subsidies can hugely impact demand.
A European epoxy resins producer estimates that about 4,500 tonnes of epoxy systems is needed for the production of several wind turbines that can generate 1 GW of electricity.
The producer estimated that globally about 15-25 gigawatt (GW) of wind farms will be installed annually in the next five years, which would require 67,500-112,500 tonnes of epoxy resins/year.
However, last year, the Chinese government cut subsidies to wind turbine producers, which resulted in a massive drop in output. Because China's national grid is not ready to transport the additional electricity generated by the wind turbines, there is now a push to upgrade the national grid before further wind farm expansions.
In the US, there is uncertainty whether the government will continue its Production Tax Credit (PTC) which subsidises the electricity created by wind turbines. Since the introduction of PTC in 1992, wind energy's share in electricity production has increased to over 10% and new installations have increased astronomically since 2001.
According to the American Wind Energy Association (AWEA), the US's installed wind power capacity has increased from 4.1 GW in 2001 to 49.8 GW in 2012, mainly because of the PTC.
But because of budget cuts, it looks likely the PTC will be discontinued, which could result in a massive drop in wind turbine output. The same epoxy resins producer expects demand will fall off a cliff and nobody will want to produce wind turbines in the first six to nine months of 2013 in the US.
In Europe, demand for wind turbines is steady, helped by offshore developments and EU targets to reduce CO2 emissions and also by the decommissioning of nuclear power stations following the Fukushima disaster in Japan last year.
Aside the uncertainties surrounding the wind energy sector, signs are promising that the share of composites will steadily grow in the aforementioned industries.
"At the moment, with the cutbacks in wind, most growth is expected to come from the aerospace industry as old planes need to be replaced and this will boost demand," the epoxy producer said.
($1 = €0.77)
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