The UK’s tidal currents could provide more than 20% of the nation's electricity needs. The country boasts around 50% of Europe’s tidal energy resource.
Britain boasts eight potential tidal power sites, making the UK a key player in the World Green Energy market. The Severn, Dee, Solway and Humber estuaries are all ideal for tidal energy generating barrages, while Islay and the Pentland Firth are to host tidal turbine arrays. The Pentland Firth, the narrow run of water between the north-east tip of Scotland and the Orkneyislands, is possibly the best place in the world to generate tidal power.
According to a study carried out by The Crown Estate, the UK can harness a potential 153GW of tidal power capacity in the UK, using three types of technology:
- Building barrages across tidal estuaries that use the ebb and flow of the waters to turn turbines. This method has been proposed for the River Severn project. Tidal barrages can provide 15%, or 96 TWh per year from 45GW of capacity, of the UK’s electricity needs
- Planting turbines underwater in fast flowing tidal streams in areas such as in coastal waters around Cornwall and Scotland. Tidal streams can potentially provide 5% or 95TWh a year from 32GW of installed capacity (potentially more with future technological development) of the UK’s power
- Tidal lagoon schemes can produce 25TWh/year, drawing on 14GW of capacity.
There is also the potential for 27GW of wave energy capacity, which could produce 69TWh of electricity a year.
- Despite the clear benefits of tidal power, there are concerns about their impact on the environment. The coalition government has rejected the Severn estuary tidal barrage scheme due to concerns for the environment. However, there are reports that ministers are open to review their decision.
- Another concern is finance. Investors in tidal technology are currently granted £40 per megawatt hour for energy generated from renewables, but this scheme will come to an end by 2017. Experts believe that this will have serious implications for the tidal power industry as it is still in the development stage. According to reports, the Severn Barrage project requires subsidies at about the same level as nuclear power stations but less than what’s offered for offshore wind plants. Experts say that the Severn project needs 30 years of support through subsidies. Thereafter, it would run for at least 90 years without support, generating electricity that’s 75% cheaper than all other forms of generation. Across its 120 year life span, the project could produce power at about £48/ MWh, less than the £88 in nuclear power costs
- Researchers have discovered that power produced by tidal turbines is not as badly affected by flicker (caused by varying loads) as wind power is
- Wave power is definitely more predictable than wind power because tidal and current stream energies are consistent.
- Tidal power increases during the winter months, when electricity demand is at its highest
- Projects are also creating jobs. The Hafren plans, involving an 11-mile (18 kilometer) barrage from Cardiff in South Wales to Weston-super-Mare in Somerset, will create about 20,000 construction jobs and 30,000 manufacturing and service jobs.
Analysts say that tidal stream power will see significant development in 2013. A company called MeyGen plans to deploy tidal stream technology in the Pentland Firth that will initially generate up to 40MW of electricity, enough to power about 38,000 homes. Already, the SeaGen project in Northern Ireland is the largest grid connected tidal turbine in the world. Recognizing tidal power’s great potential in the UK, the EU has recently announced funding in the vicinity of £30m for two UK tidal projects.
Although wave and tidal power is still in the early development stage, it is clear that this natural resource can contribute substantially to the UK's electricity needs. Through proper research, and with the help of government backing (in the form of subsidies!), a better understanding about the extent and locations of resources will help to accelerate development in a sustainable manner.