Wind power is something that most of us are by now familiar with. Wind power- the energy of the raw winds, used to turn mills, whose drive then transfers the energy to a more handy form for us humans- is now so widespread that windfarms are a common sight, and are steadily multiplying across the face of the earth.
But while wind power continues to be a popular form of renewable energy in both the public’s mind and in the policies of politicians and in government acts, a criticism of the medium persists: the intermittent nature of wind power. Coal, as long as it is abundant or easily bought on the market from elsewhere, can always be burnt. Wind, however, is not always so passive and malleable- wind farms consist of giant mills rooted deep into the ground, and are thus at the mercy of the climate and weather, which ultimately produces the aerial currents which are its ‘fuel’.
Wind farms cannot move elsewhere in order to get a better hit of wind, like a surfer who wants to find the best waves, and winds cannot be imported or moved in bulk.
One potential solution that has been proposed is a hybrid of wind power and stored hydrogen. Put simply, the hybrid system works like this: power is harnessed from the wind through mills, and this power is used for the grid (where it heats our homes, lights our buildings, etc) as well as for the additional purpose of electrolysis water, which creates hydrogen- this hydrogen is ‘bottled up’ and stored, and on those days when the wind is lagging, the hydrogen is ‘unbottled’ and used to create electricity and power- either through fuel cell technology or through a combustion engine linked to an electrical generator.
There are many issues that have arisen in the discussion and early attempts at realising wind hydrogen hybrid technology- one major issue is the storage of the hydrogen itself. Underground storage has been investigated, and is often seen as the favoured method in a possible wind-hydrogen hybrid system. Hydrogen storage is tricky because, for one thing, it requires very large tanks to hold it. Increasing the pressure for these tanks would make them smaller, but also denser. Compressed hydrogen takes up a lot of energy for the compression process, making it inefficient; hydrogen can also be kept as a liquid (think the liquid nitrogen of Hollywood films that freezes what it touches). The thing about liquefaction is that the hydrogen has to be kept very, very cold to keep it a liquid- hydrogen boils at -252.882 degrees celsius, so it has to be kept at a lower temperature than that, which takes up a hell of a lot of energy. The delicate insulation for the appropriate storage tanks is also very expensive.
Underground storage, which many would like to see as the main way of keeping hydrogen ready for power creation when the wind is running weak, would involve depleted gas and oil fields, underground caverns, or salt domes- according to Wikipedia, the chemical manufacturing giant ICI has stored gaseous hydrogen in underground caverns for years without any problems.
The Australian company WHL Energy Limited is a key player in the development of this hybrid system, and according to its website ‘is actively pursuing a regional expansion strategy in Latin America and China, in addition to the UK and Australia’. Wikipedia states that test sites for the company’s wind hydrogen system exist across Canada, Denmark, North America, Argentina, Scotland, Greece, and Norway.
A wind-hydrogen hybrid, then, looks like a positive step towards smoothing out the problems with the renewable and freely available energy that can be gained from wind- whether the difficulties of hydrogen storage can be overcome will depend upon the limits of our technology and the unfolding of time.
