Legal regulations and policy commentary: Is tidal power the way forward?

This year the government acknowledged two key challenges to the UK's long-term energy plan - the need to tackle climate change and the continuing need to provide UK-produced, affordable, clean energy.

Increasingly, the subject of harnessing tidal power has been discussed as a solution to these challenges and, most notably, the building of a tidal barrage across the Severn Estuary has been pointed at as representing a valuable untapped resource.

The building of a barrage would be a huge feat of engineering, on a level comparable with some of the world's biggest construction projects. It would be up to 16km long, power more than 200 turbines, create around 35,000 construction jobs and generate around 8,640MW of power.

In context, that's about 6% of the UK's annual energy consumption, which is the equivalent output of about 18 million tonnes of coal or three nuclear reactors. Recent figures forecast costs of £15bn and a build period of up to seven years.

Essentially, the idea behind the barrage would be for the tide to flow in and pass through the barrage. At high tide, the sluice gates would shut, which would trap water in the estuary or basin and when the tide recedes, the sluice gates would open again. The water would then flow through the barrage, driving the turbines and generating power. The Seven Estuary has always been considered a prime location for this sort of barrage as the Severn has a tidal range of up to 14m, the second-highest in the world.

Currently, the plans for the barrage are in their infancy, having been scrapped by the Thatcher government in the 1980s as too expensive and environmentally damaging. The debate over the past few months seems to have advanced and gained pace, with proponents and opponents of the project taking entrenched positions over the potential environmental implications the project may have - be they positive or negative.

However, in reality the project is still in the very early stages, and was worthy of only a brief mention in this year's Energy White Paper. The real cost-benefit has yet to be researched.

The proponents of the building of a barrage argue that it could help cut carbon emissions by up to 18 million tonnes per year, help lessen the risk of flooding in certain areas, protect against coastal erosion and contribute to a long-term sustainable solution to climate change. Opponents, such as the Environment Agency, fervently believe that a barrage would cause irreparable damage to 75% of the area's unique eco-system, which is internationally recognised as a Special Protection Area.

A barrage across the Severn Estuary would be a major national infrastructure project, contributing greatly to the UK's energy production and consumption strategy. However, as a result of the area's environmental importance, the issue essentially transcends the domestic sphere of debate and becomes an issue needing international attention.

Similarly, the project can only proceed if there are imperative reasons of overriding public importance and if adequate compensatory habitats can be found for marine and bird life elsewhere. On both accounts, the only way to proceed is through full evaluation of the bigger picture and through a detailed environmental impact assessment.

As stipulated in May's Energy White Paper a major study into harnessing tidal power in the UK has been carried out by the Sustainable Development Commission, the findings of which will inform the appropriate next steps and ultimately a national policy statement on the issue. While the top-line findings of the research are essentially positive about the role the barrage could play in future energy generation, they also lay down some tough conditions that need to be met in order for the project to be considered sustainable. They include: ensuring the project is publicly led and publicly owned, ensuring full compliance with European Directives on habitats and birds, not detracting from a wider goal of combating climate change and, ultimately, further environmental cost-benefit research.

The government has yet to publish a statement in response to the findings of the research, or outline a national policy statement detailing the role it envisages tidal power playing in the future of the energy strategy. Until it does, it is important to maintain an open mind before make a proper judgement on the issue. If the government does decide to go ahead with the project, it needs to move swiftly as there are a huge number of financial and legal hurdles to overcome before the scheme can be implemented.