Fuel cells for energy security

Conventional energy supply systems regularly have a hierarchical structure.
Electricity or gas are fed in at central nodes and then distributed downwards,
into increasingly diverse networks. Large power generation units are implemented to reduce cost and increase efficiency. They are placed at locations of good accessibility to fuel supply (e.g. imported coal) and centres of demand. With a low number of centralised power stations, though, the average distance to the customers grows and so do the losses on the electricity transmission and distribution lines. The relatively low number of generation units increases the impact of the failure of one such unit, which may be followed by major blackouts in the grids. In conventional power generation in thermal generation units, the efficiency can only be increased by building very large (several hundred MWel to GWel) units. Small installations are inherently inefficient.
The increase of renewable energy input to the grids is putting on pressure to reform the energy supply structures since renewable energies are often supplied at local level and therefore rather decentralised than centralised – PV home systems being an example of decentralised generation, though offshore windfarms are rather an example of centralised, large scale installations. Increased levels of renewable energy feed-in into electricity and gas supply grids will therefore favour decentralisation of the energy supply. A decentralised grid will be more robust to any kind of interference, be it by natural disasters – such as storms, snow storms, or flooding – or by malevolent interference, such as sabotage, or terrorist attacks, since there is no central unit that can be targeted but a multitude of small installations that will act more like a ‘swarm’ and may even be empowered to self-organise.