One of the difficulties with many Renewable EnergySources is that the are low density and widely dispersed. While it may be possible to generate Energy from these sources, the Energy has to be moved back to the sites of consumption for it to be useful. Putting power lines is not really an option as this could be extremely expensive.
One of the great things about Hydrogen and several other forms of Energy, is that they are bouyant in air. So it should be possible to float the Energy back.
Of course, it would be possible to put the Hydrogen into an AirShip and fly it back, but this in turn would take quite a lot of power to drive and steer the vehicle.
An alternative is a HydrogenBalloonNetwork. The basic idea is simple. Each EnergySource will releases Hydrogen in a balloon. While different EnergySources would probably want to use different size of balloon, they would otherwise be standardised. They would not be powered or steered, although they probably would provide some mechanism for controlling height. So each balloon would float within a specified height range, but would otherwise be free to move with the wind.
Next a set of HydrogenStations would be placed around the world. You'd need quite a few of these, probably serviced by AirShip's. This would gather balloons flying close enough and return them to the station. This would leave recycling of the balloons as only difficulty.
This system is fairly Energy efficient but not really supply sufficient. It might take quite a long time on average for a balloon to reach its end destination. This means that quite a few balloons would be needed to buffer the whole system, and increasing or decreasing the supply would be relatively slow. However, as many of the EnergySources are intermittent anyway, this would actually be an advantage. The rate at which ballons reach the HydrogenStations would be relatively insensitive to short-term changes in the rate at which they are released.
Although I like to describe this as a HydrogenBalloonNetwork, in reality the same system could transport many other forms of Energy, including Methanes from AnaerobicDigestionPlants or a combination of [[Hydrogen (providing bouyancy)] and other BioFuels such as AlgaeCake from a BioFuelGenerator. This form of transport would increase the efficency of the network as more these EnergySources are more dense.