Hydrogen plant could take tidal energy by storm

A more efficient method of producing hydrogen by electrolysis could overcome a major barrier to using wave and wind power to fuel the national grid.

If the UK is to move towards generating more electricity from renewable sources as recommended in the government’s recent energy white paper, the country must find a way of avoiding dips in supply caused by calm weather. Denmark, which uses offshore wind farms to produce electricity, has been forced to import power generated by fossil fuels from its neighbours to top up supplies.

But a team at St Andrews University in Fife claims its efficient hydrogen-generation stations could be placed near wave and wind power generators, producing the gas to create a clean way of generating electricity in a fuel cell during calm periods. During strong wind or wave conditions a percentage of power could be siphoned off to the hydrogen plant.

The new system, which relies on a super-efficient electrolyte, would then be used to create the gas, which would be stored and used to produce electricity during natural lulls.

‘Present methods of creating electricity using hydrogen from electrolysis are around 30 per cent efficient owing to the amount of power that must be used,’ said Prof John Irvine of the university’s Centre for Advanced Materials.

‘We are trying to increase this figure to 50 per cent by using an ionic conducting micro-electrolyte. The thinner the electrolyte the more current goes through it and the lower the amount of energy lost from resistance. This makes the system more efficient.’

The method is currently being patented, but Irvine says that the electrolyte is ceramic based and works at a temperature of around 400 degrees C. This is higher than the operating temperature of conventional polymer membranes and lower than that of a solid oxide system.

The researchers say Scottish tidal power alone could produce around 85 terawatts each year. ‘The Pentland Firth above John O’Groats has been described as the Saudi Arabia of tidal current power and it has been estimated that, given suitable technology, it could supply more than 15 terawatt hours per annum,’ said Irvine.

‘This represents half the electricity consumption for Scotland.’