Changing attitudes to tidal power
In October 2007, the Sustainable Development Commission (SDC) published a report which suggested that we could meet 10% of our electricity need, cleanly, by harnessing rivers and tides.
The SDC report also highlighted the fact that, despite limited official support, the UK was the world leader in the development of tidal technology, thanks to the persistence, vision and effort of a small number of engineers and scientists.
Tidal power in the UK
Although the River Severn alone accounts for 80% of the potential tidal range resource, other sites including the Firth of Forth and Sutherland in Scotland, Anglesey in North Wales, and the Mersey and Humber estuaries in England could be viable additional sites for tidal range or tidal stream (marine current) systems.
SeaGen is the world’s first commercial scale tidal stream energy generator, and is to be built in Northern Ireland. Watch the SeaGen video and read the case study.
How tidal power works
Typically, a barrier is built across a tidal basin or inlet, with the incoming tide allowed to flow freely into a catchment area via sluices. These are then shut and the trapped water diverted down channels to turn electricity generating turbines.
A newer approach is to mount turbines on the sea bed, ready to harvest the energy of fast flowing tidal currents in much the same way that wind turbines capture the energy above the water. Building a tidal power generator presents a number of specific challenges.
Although building large-scale installations in marine environments – especially those with strong currents and tides – can be difficult, it is well within the normal engineering skill set. Machinery operating underwater must be built to exacting tolerances to minimise the need for regular maintenance, as maintenance offshore can be difficult, dangerous and expensive. The power generated must be brought to shore via cable and the generator itself carefully located so as minimise the impact on the environment or shipping.
Efficiency of tidal power
The key benefit of tidal range power is its remarkable efficiency: once constructed, up to 80% of the potential energy of the water ‘captured’ can be converted to electricity, with no greenhouse emissions. Tidal energy is also attractive from the point of view of energy security - making use of resources naturally available on and around our own shores.
Tidal power in action: SeaGen case study
Engineering company Marine Current Turbines installed SeaGen, the world’s first commercial scale tidal stream energy generator in Northern Ireland. Read the case study of tidal power in action.