Saturday, November 3, 2012

Wind energy storage methods and projects – Part 1

Wind and solar are currently two the most popular renewable energy sources in the world but they are still unable to replace fossil fuels and become primary energy option. One of the things that wind and solar will have to find solution for is their intermittency.

Intermittency of wind energy means that wind is uncontrollably variable or more intermittent than fossil fuels because wind doesn't blow all day long. This is the reason why wind energy needs adequate energy storage solution in order for wind to be considered reliable in times when wind turbines do not produce enough power.

The adequate wind energy storage method must not only provide high efficiency but must also be cheap enough for commercial production. The science is still looking for the storage method that would best comply with these two demands, and there have been some rather interesting projects.

The Danish researchers, for instance, have showed that storing wind energy in giant synthetic air bags buried under sand dunes is connected with excellent efficiency of 97%. This energy storage method is based on wind powered compressors that inflate the bags, and afterwards the compressed air gets released to generate power using exactly the same kind of pump and turbine system used for energy storage in lakes.

This method satisfies the demand for high efficiency but still has to find solutions for several issues such as how to ensure that the massive air bags would be able to handle repeated inflation and deflation. The Danish researchers who did this experiment believe that the solution for this can be found in form of synthetic membrane. When they used synthetic membranes air bags only stretched 0.5 percent, and these membranes are constructed to withstand tension of up to 14 percent.

Air bags are just one of several proposed methods to store wind energy. Other potential solutions include hybrid batteries which would be able to store electricity but this solution is still connected with significant costs meaning it has plenty to improve in terms of commerciality.

The continuing technological and scientific advancement will hopefully lead to new cost-effective wind energy storage method(s) that would remove this significant drawback of wind energy, thus opening door for much bigger use of wind turbines in years to come.