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The growing use of wind farms has brought forth the problem of synchronizing the power supply with the periods of peak energy needs. Hawaii has been facing the problem of importing or exporting power to the companies nearby, which is a problem with regards to its aim of having 70% of its demands met by renewable sources. Storage batteries have been decided as the most efficient solution. They would allow harnessing energy at some of the windiest locations in Hawaii. A 30-megawatt wind farm is being planned in association with the Texas-based company, Xtreme Power. A 15-megawatt battery will be installed and controlled by computers to overcome fluctuations while having its frequency regulated at 60 cycles per second. This is capable of maintaining 10 megawatt-hours of energy to deliver power in peak periods. The expenses are estimated in the range of $130 million. There have been other projects going on in the country which utilize storage batteries. The Beacon Power project near Albany with 200 flywheels of a ton each, two projects run by PSEG Global in New Jersey and the Texas-based four-megawatt battery system project completed by the American Electric Power and MidAmerican Energy Holdings are some related endeavors.

Article - http://www.cnn.com/2010/TECH/science/01/26/eco.energy.grid/index.html

Europe has come up with the solution for unexpected unavailability of alternative sources of energy. They have made plans for constructing a large scale electricity grid uniting the renewable resources available in different parts of northern Europe. France, Denmark, Netherlands, Luxembourg, Ireland, UK, Sweden, Belgium and Germany are the countries which have joined hands towards the fulfillment of the European Union's aim of dedicating renewable resources for 20% of their energy needs by 2010. Cables constructed under the sea will connect the solar arrays in Germany to the hydroelectric resources of Norway and tidal power stations in Belgium to the wind farms of Britain. Not only will this allow switching to another green power resource whenever needed, but this will also augment the European economy by creating several jobs. This project ranging across the English Channel, Baltic Sea and the Irish Sea is expected to cost about $20 to $40 billion. This endeavor is a positive step towards the European "supergrid" which would cover the solar farms in Africa and Central Europe. Gathering adequate finances, obtaining the requisite permissions and planning grid access regulations are some barriers which need to be overcome. However considering the abundant international support, the project is expected to complete by 2050.