Increasingly, attention is being paid to the tidal power around Scotland's coast as the search builds to take more energy from renewable sources. The Pentland Firth in particular contains a huge surge of power – it has been estimated that around 2.5 million cubic metres flow through the Firth every second when it is in full flow which, it is said, could produce up to 20 gigawatts of energy.

One problem is shipping the power down from the north of Scotland to the conurbations in central Scotland and further south. The grid does not currently boast the capacity to accommodate major tidal power projects and this underlines the importance of a rapid resolution of the Beauly to Denny power line debate, whether that is an approval of the currently proposed upgrade or an identification of a suitable alternative.

Notwithstanding the capacity constraints, a number of companies are looking seriously at tidal power's potential.

In 2008, Scottish Power will commence testing a subsea turbine in the Pentland Firth and English company MCT is also reported to be working on a similar turbine.

Environmentally, some commentators are warning that preparatory studies are required first to ensure no or minimised impact on the marine environment and it is thought that detailed environmental impact assessments will precede any major installation in the Pentland Firth. Many advocates of tidal power though point out that the environmental impact of subsea tidal turbines is likely to be very much less than, for example, onshore wind farms.

How quickly will the tidal power sector expand? Looking at the track record to date, the answer may well be 'slowly'. The European Marine Energy Centre and Ocean Power Delivery have been amongst those working hard to develop marine renewable energy devices but progress (in terms of actually deployed machines or turbines) has been gradual rather than meteoric.

The plans announced in the government's recently released Energy White Paper to rejig the renewable obligation certificates regime may though act as a significant fillip to encourage more developers to consider marine, and specifically tidal, power projects.