A new report recommends that the UK should turn to tidal power as a source of electricity. Wave power is being recommended over wind power as a renewable energy alternative. This is according to the latest research which shows that estuary barrages and tidal streams could provide over 20% of the nation's electricity needs.
The UK, an island which is surrounded by seas, is an ideal candidate for tidal power, explains the report published in the journal "Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences." The country ranks first in Europe in terms of assessed marine energy potential.
Tidal power is harnessed in two ways:
Building barrages across tidal estuaries that use the ebb and flow of the waters to turn turbines. This method is being used for the River Severn project. This method will provide the UK with 15% of its electricity needs
Planting turbines underwater in fast flowing tidal streams such as in coastal waters around Cornwall and Scotland. This method will provide the UK with at least 5% of its electricity demand.
Researchers say that both methods can be used in the UK. Already, there are plans to develop tidal stream technology in Pentland Firth by a firm called MeyGen. On completion, the project is expected to generate up to 40MW of electricity, powering up to 38,000 households. This will be the UK’s first array of tidal stream turbines. Northern Ireland is host to the SeaGen project which is the largest grid connected tidal turbine in the world.
Experts say that despite the high costs, the advantages of tidal power far outweigh that of wind power:
Tidal power is more uniform and reliable than wind power
Tides are predictable as they rise with great uniformity. This is unlike intermittent sources like solar and wind
The quality of tidal power is good and surpasses that of old wind energy turbines
Flicker levels are low (in comparison to older wind turbines in operation)
It is renewable and non-polluting, unlike fossil fuels
No fuel needed-only water!
Running costs are low-The biggest Power Plant in France, run by EDF, works at 1.5c/Kwh which is lower than either nuclear or coal energy which are the cheapest forms of power.
Long Life- A Tidal Barrage has a very long life of around 100 years- much longer than that of even Nuclear Power Plants. The long life implies that the life cycle cost of a Tidal Energy Power Plant becomes very low in the long term
High energy density –higher than wind power
High load factor-almost on a par with fossil fuels
Despite the positive aspects of tidal power, there are two major drawbacks that the industry faces. Project finance is one and withdrawal of subsidies, is the other. Investors in tidal technology are currently given £40/MWh for energy generated from renewables, but this scheme will end within the next four years. According to Professor AbuBakr Bahaj from the University of Southampton, this could cause serious implications for the emerging industry. He explains: “It depends on the subsidy. Without it, it wouldn't stack up financially."
Other tidal power cons are as follows
High initial capital investment
Limited locations- the US DOE estimates that there are only about 40 locations in the world capable of supporting Tidal Barrages. This is because Tidal Energy Technology needs sizable Tides for the Power Plant to be built.
Negative impact on marine life-commercial tidal power stations can have a disruptive effect on marine life.
Immature Technology-technology can be rather costly, immature and unproven
Long gestation time-the projects can experience long and costly delays which may result in cancellations. Many plants will never see completion as a result.
Difficulty in Transmission of Tidal Electricity- some forms of Tidal Power generation are far away from the consumption of electricity. Transportation of Tidal Energy can be quite cumbersome and costly
Weather effects-severe weather can be devastating on tidal power equipment. This is especially true for equipment placed on the sea floor.
Tidal energy, like all other forms of energy, has its advantages and disadvantages. Innovative methods and technology are constantly being developed to harness tidal and wave energy. This will eventually see tidal energy move into the mainstream energy industry.
Tidal power will give the UK another element in the energy mix, offering more reliability than wind. As understanding about the extent and locations of resources improve, development in the industry will be accelerated in a sustainable way.